bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phenotypic evolution and hidden speciation in Candidula unifasciata ssp. (Helicellinae, Gastropoda) inferred by 16S variation and quantitative shell traits
Authors: Pfenninger Markus , Magnin Frédéric 
Published: March 2003

AbstractIn an effort to link quantitative morphometric information with molecular data on the population level, we have analysed 19 populations of the conchologically variable land snail Candidula unifasciata from across the species range for variation in quantitative shell traits and at the mitochondrial 16S ribosomal (r)DNA locus. In genetic analysis, including 21 additional populations, we observed two fundamental haplotype clades with an average pairwise sequence divergence of 0.209 ± 0.009 between clades compared to 0.017 ± 0.012 within clades, suggesting the presence of two different evolutionary lineages. Integrating additional shell material from the Senckenberg Malacological Collection, a highly significant discriminant analysis on the morphological shell traits with fundamental haplotype clades as grouping variable suggested that the less frequent haplotype corresponds to the described subspecies C. u. rugosiuscula, which we propose to regard as a distinct species. Both taxa were highly subdivided genetically (FST = 0.648 and 0.777 P < 0.001). This was contrasted by the partition of morphological variance, where only 29.6% and 21.9% of the variance were distributed among populations, respectively. In C. unifasciata, no significant association between population pairwise FST estimates and corresponding morphological fixation indices could be detected, indicating independent evolution of the two character sets. Partial least square analysis of environmental factors against shell trait variables in C. u. unifasciata revealed significant correlations between environmental factors and certain quantitative shell traits, whose potential adaptational values are discussed.
Strategies for microsatellite isolation: a review
Authors: Zane L , Bargelloni L , Patarnello T 
Published: March 2003

AbstractIn the last few years microsatellites have become one of the most popular molecular markers used with applications in many different fields. High polymorphism and the relative ease of scoring represent the two major features that make microsatellites of large interest for many genetic studies. The major drawback of microsatellites is that they need to be isolated de novo from species that are being examined for the first time. The aim of the present paper is to review the various methods of microsatellite isolation described in the literature with the purpose of providing useful guidelines in making appropriate choices among the large number of currently available options. In addition, we propose a fast and easy protocol which is a combination of different published methods.
Population fragmentation in the southern rock agama, Agama atra: more evidence for vicariance in Southern Africa
Authors: Matthee Conrad A. , Flemming Alexander F. 
Published: March 2003

AbstractMitochondrial DNA sequence data derived from two genes were used to infer phylogeographical relationships between 13 Agama atra populations. Three distinct geographical assemblages were found among the lizard populations. The first occurs in southern Namibia, the second is restricted to the western dry arid regions of South Africa, whereas the third is distributed throughout the more mesic southern and eastern parts of the subcontinent. Geographically structured differences among populations within Agama clades are probably the result of dispersal and historic isolations among populations. At the broader scale, there were marked congruences between the Agama genetic discontinuities and those described previously in other rock‐dwelling vertebrates such as Pronolagus rupestris and Pachydactylus rugosus. This suggests vicariance, probably as a response to natural climatic changes during the past three million years.
Genetic diversity in Arabidopsis thaliana L. Heynh. investigated by cleaved amplified polymorphic sequence (CAPS) and inter‐simple sequence repeat (ISSR) markers
Authors: Barth S. , Melchinger A. E. , Lübberstedt TH. 
Published: March 2003

AbstractIn this study, we investigated genetic diversity among 37 accessions in Arabidopsis thaliana from Eurasia, North Africa and North America using morphological traits and two polymerase chain reaction (PCR)‐based marker systems: cleaved amplified polymorphic sequences (CAPS) and inter‐simple sequence repeats (ISSR). Cluster analysis based on genetic similarities calculated from CAPS data grouped the accessions roughly according to their geographical origin: one large group contained accessions from Western, Northern and Southern Europe as well as North Africa, a second group consisted of Eastern European and Asian continental accessions. North American accessions were interspersed into these groups. Contrary to the CAPS analysis, the dendrogram obtained from the ISSR data did not reflect the geographical origin of the accessions, and the calculated genetic distances did not match the CAPS results. This could be attributable to an uneven genomic distribution of ISSR markers as substantiated by a database search for ISSR binding sites in A. thaliana genomic DNA sequence files, or to the ISSR’s different mode of evolution. We recommend CAPS markers for diversity analysis in A. thaliana because a careful selection of markers can ascertain an even representation of the entire genome.
Bodyfat percentage in girls increased steadily with age and percentile rank of body mass index
Authors: Yoshinaga Masao , Shimago Atsushi , Noikura Yoshihide , Kinou Sanae , Ohara Tsuruo , Miyta Koichiro 
Published: March 2003

Abstract
Background
: The purpose of the present study was to determine the body composition of elementary school children by bioelectrical impedance analysis (BIA) method with a subject in a standing position. The method is frequently used in Japan. The other aim was to evaluate the relationship between the body composition and percentile rank of the body mass index (BMI) in Japanese children.
Methods
: The number of subjects were 1042 children (530 boys and 512 girls aged from 6‐ to 12‐years‐old) from an elementary school. The bioelectrical impedance (BI) in the standing position was measured late in the morning before lunch. The fat percentage was derived from the body density according to the formula of Brozek et al. Each percentile value of BMI for each age and sex was determined from the frequency table of height and weight published by the Ministry of Education in Japan.
Results
: The fat percentage in both boys and girls was significantly correlated with the BMI, however, girls showed a closer linear relation than boys. The fat percentage in girls increased steadily with age and percent rank of the BMI. The fat percentage in boys was scattered in a wide range at each percentile rank of the BMI.
Conclusions
: The fat percentage measured by the BIA in the standing position is closely associated with the percentile rank of the BMI in elementary school girls. For boys, it will be necessary to compare data among different types of BI measurement methods.
Venous thromboembolic diseases associated with uterine myomas diagnosed before hysterectomy: A report of two cases
Authors: Tanaka Hirohiko , Umekawa Takashi , Kikukawa Toyo , Nakamura Mashio , Toyoda Nagayasu 
Published: March 2003

AbstractLarge uterine myomas (compressed veins in the pelvis), and the resulting impaired blood flow have been associated with deep vein thrombosis and pulmonary embolism. Careful detection of the preoperatively formed thrombi and strict perioperative management, such as in the following cases we report, may reduce lethal pulmonary embolism and may positively affect patient prognosis.
Cell‐to‐cell movement of tobacco mosaic virus: enigmas and explanations
Authors: Rhee Yoon , Tzfira Tzvi , Chen Min‐Huei , Waigmann Elisabeth , Citovsky Vitaly 
Published: March 2003

AbstractTobacco mosaic virus (TMV) spreads between cells through plant intercellular connections, the plasmodesmata. This transport process is mediated by a specialized virus‐encoded movement protein, TMV MP. Recent advances in two major aspects of TMV MP function highlight the limits of our current knowledge and promise exciting future developments. First, findings that TMV MP interacts with cytoskeletal elements and cell wall proteins suggest potential mechanisms for TMV MP targeting from the cell cytoplasm to plasmodesmal channels. Second, indications that TMV MP phosphorylation plays a regulatory role in several activities of TMV MP begin to unravel molecular pathways that control TMV cell‐to‐cell transport. TMV systemic movement that follows its initial cell‐to‐cell spread, on the other hand, may be controlled through two different pathways used for viral entry into and exit from the host plant vascular tissue.
Regulation of carbohydrate partitioning during the interaction of potato virus Y with tobacco
Authors: Herbers K. , Takahata Y. , Melzer M. , Mock H.‐P. , Hajirezaei M. , Sonnewald U. 
Published: March 2003

AbstractTo test whether carbohydrates may play a signalling function during plant pathogenesis, we investigated the interaction between tobacco and potato virus Y (PVYN). Four days after PVYN infection, leaves started to accumulate soluble sugars and leaf photosynthesis decreased. The accumulation of soluble sugars was accompanied by an induction of cell wall invertase and a gradual decrease in the sucrose‐to‐hexose ratio. In parallel to changes in carbohydrate metabolism and photosynthesis, transcripts encoding PR‐proteins accumulated. Based on this coincidence, it was hypothesized that elevated hexose levels may enhance the expression of defence‐related functions and might possibly explain the phenomenon of high sugar resistance in plants. This notion has been supported by the fact that cell wall invertase‐expressing transgenic tobacco plants were found to be resistant against PVYN (
Herbers et al., 1996b
). To exclude the possibility that salicylate, which accumulates in plants expressing invertase, may be responsible for the observed resistance, these transgenic plants were crossed with salicylate hydroxylase‐expressing plants (nahG). The progeny were selected for high levels of sugar and low levels of salicylate. Necrotic lesions also developed, typically formed on the leaves of plants expressing invertase, and transcripts encoding PR‐Q accumulated in the absence of salicylate. On the other hand, accumulation of PR‐1b transcripts decreased, indicating that sugars are not sufficient for PR‐1b induction. Infection experiments using these plants as hosts revealed resistance towards PVYN. Thus, the mechanism of apoplastic invertase induced virus resistance is salicylate independent and most likely sugar mediated.
Plant signalling and induced defence in insect attack
Authors: Chamberlain Keith , Pickett John A. , Woodcock Christine M. 
Published: March 2003

AbstractPlants can produce compounds which act as semiochemicals, that is, signals modifying the development or behaviour of other organisms without having direct physiological activity. Among such semiochemicals are plant stress signals associated with the induction of defence systems, and these may include phytopheromones that naturally influence plant development. It is well known that plant‐derived semiochemicals can be exploited by colonizing organisms, particularly pathogens and insect pests. Recently proposed external signals not yet proven as natural phytopheromones are nitric oxide and the volatile methyl esters of jasmonic and salicylic acids. Since it is now possible to use sophisticated electrophysiological techniques to investigate insect interactions with prospective phytopheromones, the detection and characterization of signalling systems has been made much easier and can provide a molecular characterization of signals that are active beyond the insects themselves. In addition to the advances these studies have brought to the understanding of plant/insect and plant/plant interactions, plant signals are potentially valuable in the regulation of gene expression for improved or alternative approaches to crop protection or for other developmental processes in plants.
How the bacterial plant pathogen Xanthomonas campestris pv. vesicatoria conquers the host
Authors: Bonas Ulla , Van den Ackerveken Guido , Büttner Daniela , Hahn Karoline , Marois Eric , Nennstiel Dirk , Noel Laurent , Rossier Ombeline , Szurek Boris 
Published: March 2003

Abstract Xanthomonas campestris pv. vesicatoria (Xcv) is the causal agent of bacterial spot disease on pepper and tomato. Pathogenicity on susceptible plants and the induction of the hypersensitive reaction (HR) on resistant plants requires a number of genes, designated hrp, most of which are clustered in a 23‐kb chromosomal region. Nine hrp genes encode components of a type III protein secretion apparatus that is conserved in Gram‐negative plant and animal pathogenic bacteria. We have recently demonstrated that Xcv secretes proteins into the culture medium in a hrp‐dependent manner. Substrates of the Hrp secretion machinery are pathogenicity factors and avirulence proteins, e.g. AvrBs3. The AvrBs3 protein governs recognition, i.e. HR induction, when bacteria infect pepper plants carrying the corresponding resistance gene Bs3. Intriguingly, the AvrBs3 protein contains eukaryotic signatures such as nuclear localization signals (NLS), and has been shown to act inside the plant cell. We postulate that AvrBs3 is transferred into the plant cell via the Hrp type III pathway and that recognition of AvrBs3 takes place in the plant cell nucleus.
DNA and protein transfer from bacteria to eukaryotes— the agrobacterium story
Authors: Nester EugenE. W. 
Published: March 2003

Abstract Agrobacterium is a well‐studied plant pathogen, which has the unique ability to transfer DNA and protein into a number of eukaryotes. The DNA is integrated randomly into the plant genome where it is expressed, thereby leading to the disease crown gall. This system is a paradigm for the interaction of a number of plant and animal pathogens which transfer proteins into their host cells. In Agrobacterium, the tumour inducing (Ti) plasmid codes for the functions specifically required for the transfer process. These genes, termed virulence or vir genes, are activated by plant signal molecules acting through a two component regulatory system. A key structure coded by 11 genes of the vir B operon is a pilus, synthesized at 20 °C, but poorly at 25 °C. How this pilus functions in DNA and protein transfer is unclear, but homologous genes are found in many animal pathogens. In addition to Ti plasmid‐encoded vir genes, chromosomal virulence genes have also been identified. However, these mutations are often pleiotropic because they involve both the normal physiology of Agrobacterium as well as the metabolism of Agrobacterium when it is associated with plant cells. Based on 16S ribosomal RNA sequencing, Agrobacterium is closely related to the intracellular pathogen of animals, Brucella. Several chromosomal mutations of Agrobacterium required for virulence in plants are also required for invasion of animal host cells by Brucella.
Cucumber mosaic virus, a model for RNA virus evolution
Authors: Roossinck Marilyn J. 
Published: March 2003

SummaryTaxonomic relationships: Cucumber mosaic virus (CMV) is the type member of the Cucumovirus genus, in the family Bromoviridae. Additional members of the genus are Peanut stunt virus (PSV) and Tomato aspermy virus (TAV). The RNAs 3 of all members of the genus can be exchanged and still yield a viable virus, while the RNAs 1 and 2 can only be exchanged within a species.Physical properties: The virus particles are about 29 nm in diameter, and are composed of 180 subunits (T = 3 icosahedral symmetry). The particles sediment with an s value of approximately 98. The virions contain 18% RNA, and are highly labile, relying on RNA–protein interactions for their integrity. The three genomic RNAs, designated RNA 1 (3.3 kb in length), RNA 2 (3.0 kb) and RNA 3 (2.2 kb) are packaged in individual particles; a subgenomic RNA, RNA 4 (1.0 kb), is packaged with the genomic RNA 3, making all the particles roughly equivalent in composition. In some strains an additional subgenomic RNA, RNA 4A is also encapsidated at low levels. The genomic RNAs are single stranded, plus sense RNAs with 5′ cap structures, and 3′ conserved regions that can be folded into tRNA‐like structures.Satellite RNAs: CMV can harbour molecular parasites known as satellite RNAs (satRNAs) that can dramatically alter the symptom phenotype induced by the virus. The CMV satRNAs do not encode any proteins but rely on the RNA for their biological activity.Hosts: CMV infects over 1000 species of hosts, including members of 85 plant families, making it the broadest host range virus known. The virus is transmitted from host to host by aphid vectors, in a nonpersistent manner.Useful web sites: http://mmtsb.scripps.edu/viper/1f15.html (structure); http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/10040001.htm (general information)
The tobacco mosaic virus resistance gene, N
Authors: Marathe Rajendra , Anandalakshmi Radhamani , Liu Yule , Dinesh‐Kumar S. P. 
Published: March 2003

SummaryIn this mini review we discuss recent advances in the understanding of the N gene‐mediated resistance to tobacco mosaic virus (TMV). The tobacco N gene belongs to toll‐interleukin‐1 receptor homology/nucleotide binding/leucine rich repeat (TIR‐NB‐LRR) class of resistance genes. It encodes two transcripts, NS and NL, by alternative splicing, both of which are required to confer resistance to TMV. The structure–function analysis of the N gene indicates that the TIR, NB and LRR domains are indispensable for its function. The N gene response is elicited by the C‐terminal helicase domain of the 126 kDa TMV replicase protein. Tobacco N gene can also confer resistance to TMV in heterologous plants like tomato and Nicotiana benthamiana. Recent studies on N‐mediated signalling suggest that EDS1, Rar1 and NPR1 genes play an important role in TMV resistance. Finally, we discuss current status of the N‐mediated signal transduction and speculate directions for future work to understand N–TMV interaction.
The phenylpropanoid pathway and plant defence—a genomics perspective
Authors: Dixon Richard A. , Achnine Lahoucine , Kota Parvathi , Liu Chang‐Jun , Reddy M. S. Srinivasa , Wang Liangjiang 
Published: March 2003

SummaryThe functions of phenylpropanoid compounds in plant defence range from preformed or inducible physical and chemical barriers against infection to signal molecules involved in local and systemic signalling for defence gene induction. Defensive functions are not restricted to a particular class of phenylpropanoid compound, but are found in the simple hydroxycinnamic acids and monolignols through to the more complex flavonoids, isoflavonoids, and stilbenes. The enzymatic steps involved in the biosynthesis of the major classes of phenylpropanoid compounds are now well established, and many of the corresponding genes have been cloned. Less is understood about the regulatory genes that orchestrate rapid, coordinated induction of phenylpropanoid defences in response to microbial attack. Many of the biosynthetic pathway enzymes are encoded by gene families, but the specific functions of individual family members remain to be determined. The availability of the complete genome sequence of Arabidopsis thaliana, and the extensive expressed sequence tag (EST) resources in other species, such as rice, soybean, barrel medic, and tomato, allow, for the first time, a full appreciation of the comparative genetic complexity of the phenylpropanoid pathway across species. In addition, gene expression array analysis and metabolic profiling approaches make possible comparative parallel analyses of global changes at the genome and metabolome levels, facilitating an understanding of the relationships between changes in specific transcripts and subsequent alterations in metabolism in response to infection.
A newly identified role for Tomato bushy stunt virus P19 in short distance spread
Authors: Turina Massimo , Omarov Rustem , Murphy John F. , Bazaldua‐Hernandez Cynthia , Desvoyes Bénédicte , Scholthof Herman B. 
Published: March 2003

SUMMARYThis study identified a role for the Tomato bushy stunt virus (TBSV) p19 protein (P19) in local lesion expansion on cowpea (Vigna unguiculata), and cell‐to‐cell movement in pepper (Capsicum annuum). The contribution to short distance spread in both hosts was strongly influenced by a cluster of charged amino acids between positions 72 and 78 on the 172 amino acid P19. Charged amino acids near this region between positions 43 and 85 were required for long distance spread in pepper. These results indicate that the central domain of P19 plays a key role for its activities in TBSV movement and that additional regions on this protein contribute to virus spread in a host‐specific manner.
Composition and nutritional value of commercial dried whey products from feta cheese manufacture
Authors: Boumba V A , Voutsinas L P , Philippopoulos C D 
Published: March 2003

Various commercial dried whey products—WHEYPRO20, WHEYPRO35 and WHEYPRO65 (with approximately 20, 35 and 65% protein, respectively) and LACTINA (a permeate powder)—were studied in terms of chemical composition and nutritional value. These products were produced industrially from the whey of feta cheese manufactured with ovine and caprine milk by ultrafiltration and subsequent evaporation and spray‐drying. As the protein content in these products increased, the nonprotein nitrogen and fat contents increased while the lactose and ash contents decreased. Generally the concentration of minerals (Ca, P, Na, K, Cl) in these products decreased with increasing protein content. With the exception of valine and methionine + cysteine, all essential amino acids were in excess in the whey protein concentrates (WHEYPRO35 and WHEYPRO65) as compared with the Food and Agriculture Organization reference protein and with human milk protein.
Designing a search strategy to identify and retrieve articles on evidence‐based health care using MEDLINE
Authors: HARRISON JANE 
Published: March 2003

The practice of evidence‐based health care requires that information on methodology be identified from databases such as MEDLINE. Up until this year there have been no designated medical subject headings (MeSH) for evidence‐based health care. ‘EVIDENCE‐BASED MEDICINE’ appears as a MeSH term from 1997. The absence of designated MeSH for this concept prior to 1997 provides a challenge to the searcher. This paper describes the creation of a MEDLINE search strategy to retrieve articles on the methods of evidence‐based health care published prior to the introduction of the new term, where an optimal combination of free‐text and MeSH terms is required to identify relevant material. The study examines both free‐text and subject heading searching and attempts an optimal balance of sensitivity and specificity. It begins by examining separate free‐text and subject heading searches. Sensitivity of the subject heading search was 33% and specificity 80%, while the free‐text search produced a sensitivity of 50% and a specificity of 67%. The final strategy, combining both approaches, was more successful with sensitivity reaching between 82 and 90% and specificity 83%.It is therefore possible to devise a search strategy to retrieve articles on the methods of evidence‐based health care with relatively successful rates ofsensitivity and specificity. The limitations of MEDLINE, however, necessitate the use of additional approaches in identifying articles on the methods of evidence‐based health care.