Summary
In physiological conditions, red blood cells (RBCs) are capable of dramatic deformations when passing through the microvasculature. This extreme deformability is closely related to the RBC ...biconcave shape, to the fluidic nature of the haemoglobin and the cell membrane structure, primarily consisting of a phospholipid bilayer with an underlying two‐dimensional spectrin network. In many pathological and inflammatory conditions, the shape and the extreme deformability of erythrocytes appear to be significantly altered. These findings have stimulated intense research towards the search and validation of novel erythrocyte‐based mechanical biomarkers, useful for disease diagnosis and therapy monitoring. In this study, we investigated with Atomic Force Microscopy (AFM) the mechanical properties of erythrocytes obtained from a 68 years old cirrhotic man diagnosed with spur cell anaemia and cold agglutinated disease, before and after liver transplantation. Mechanical changes are compared with ultrastructural alterations as studied by scanning electron microscopy and discussed according to confocal fluorescence microscopy results, showing possible alterations induced by the cirrhotic environment at the level of the RBCs cytoskeletal organisation and lipidic composition. Taken together, the results here presented show that liver transplantation not only contributes to restoring the proper RBC morphology, but it also induces recovery of the physiological viscous behaviour of cells, further stressing the relevance of viscous and dissipative forces in determining the RBC biomechanical response.
Expressed sequence tags (ESTs) in public databases and cross-species transferable markers are considered to be a cost-effective means for developing sequence-based markers for less-studied species. ...In this study, EST-simple sequence repeat (SSR) markers developed from Lathyrus sativus L. EST sequences and cross-transferable EST-SSRs derived from Medicago truncatula L. were utilized to investigate the genetic diversity among grass pea populations from Ethiopia. A total of 45 alleles were detected using eleven EST-SSRs with an average of four alleles per locus. The average polymorphism information content for all primers was 0.416. The average gene diversity was 0.477, ranging from 0.205 for marker Ls942 to 0.804 for MtBA32F05. F ST values estimated by analysis of molecular variance were 0.01, 0.15, and 0.84 for among regions, among accessions and within accessions respectively, indicating that most of the variation (84%) resides within accessions. Model-based cluster analysis grouped the accessions into three clusters, grouping accessions irrespective of their collection regions. Among the regions, high levels of diversity were observed in Gojam, Gonder, Shewa and Welo regions, with Gonder region showing a higher number of different alleles. From breeding and conservation aspects, conducting a close study on a specific population would be advisable for genetic improvement in the crop, and it would be appropriate if future collection and conservation plans give due attention to under-represented regions.
The genomic and cDNA sequences of three PDI homoeologous genes located on chromosomes 4A, 4B and 4D of bread wheat and their promoters were cloned and sequenced. The three sequences showed a very ...high conservation of the coding region and of the exon/intron structure, which consisted of ten exons. The comparison of wheat sequences with those of rice and
Arabidopsis showed a significant conservation of the exon/intron structure across the three species. The expression of each gene was analysed by RT-PCR in different plant tissues (roots, coleoptiles, spikelets, leaves and developing caryopses). All the genes showed a higher expression in developing caryopses than in other analysed tissues, wherein some differences were detected. The promoter sequences of the three genes possessed some regulatory motifs typical of endosperm specific expression.
A study of the extent and patterns of microsatellite diversity in 234 genotypes from Ethiopian durum wheat (Triticum turgidum) landraces was conducted to identify areas of diversity that could be ...used as a source of new germplasm for developing high yielding and stable varieties. Landraces belonging to nine populations, from three Ethiopian regions Tigray (T), Gonder (G) and Shewa (S) with different climates, were analysed by using 28 simple sequence repeat (SSR) markers. The level of polymorphism was high and quite consistent among populations underlining the great diversity existing. The highest level of diversity was found within populations, about 75.9%, while about 5.3% was attributed to differences between regions. The level of expected heterozygosity was on an average, rather high, ranging from 39% to 56%, whereas the observed heterozygosity was, on an average, limited to 14%. An average of about five alleles per locus was detected in each population. Nevertheless, alleles were not equally present in populations as confirmed by the high level of expected heterozygosity. The polymorphism information content (PIC) for the markers assessed showed a wide range of values from 0.14 to 0.92. The likelihood relationships among the nine Ethiopian populations indicated that the material collected in the Gonder region (a wet climate) was genetically more diverse than the materials from Shewa and Tigray (dryer climates). The high number of loci in linkage disequilibrium (LD), up to 23, has demonstrated that the loci were associated irrespective of their physical location. This holds true even if the loci are located on different chromosome arms. Genetic diversity values between populations was very different and was used to produce a dendrogram showing population relationships.
Durum wheat (Triticum turgidum L. var. durum) is an economically and nutritionally important cereal crop in the Mediterranean region. To further our understanding of durum genome organization we ...constructed a durum linkage map using restriction fragment length polymorphisms (RFLPs), simple sequence repeats (SSRs) known as Gatersleben wheat microsatellites (GWMs), amplified fragment length polymorphisms (AFLPs), and seed storage proteins (SSPs: gliadins and glutenins). A population of 110 F^sub 9^ recombinant inbred lines (RILs) was derived from an intraspecific cross between two durum cultivars, Jennah Khetifa and Cham 1. The two parents exhibit contrasting traits for resistance to biotic and abiotic stresses and for grain quality. In total, 306 markers have been placed on the linkage map - 138 RFLPs, 26 SSRs, 134 AFLPs, five SSPs, and three known genes (one pyruvate decarboxylase and two lipoxygenases). The map is 3598 cM long, with an average distance between markers of 11.8 cM, and 12.1% of the markers deviated significantly from the expected Mendelian ratio 1:1. The molecular markers were evenly distributed between the A and B genomes. The chromosome with the most markers is 1B (41 markers), followed by 3B and 7B, with 25 markers each. The chromosomes with the fewest markers are 2A (11 markers), 5A (12 markers), and 4B (15 markers). In general, there is a good agreement between the map obtained and the Triticeae linkage consensus maps. This intraspecific map provides a useful tool for marker-assisted selection and map-based breeding for resistance to biotic and abiotic stresses and for improvement of grain quality.PUBLICATION ABSTRACT
Seedlings of Phillyrea latifolia L., a Mediterranean shrub, were exposed for 90 days to 110 nl l(-1) ozone (O3). Comparison of the cDNA-amplified fragment length polymorphism (cDNA-AFLP) patterns for ...treated and control plants allowed the identification and cloning of 88 differential sequences induced by O3. The differential expression of 67 cloned sequences was further confirmed by RT-PCR. The functions of 36 cloned sequences, corresponding to seven of the twelve gene functional classes of Arabidopsis, were presumed on the basis of their homology with characterized gene sequences. Ozone induction of genes homologous to 24 of the clones has been reported in other plant species, whereas the induction of the 12 remaining sequences has not been observed before. Ozone activation of these newly identified genes could be a result of the chronic exposure to low O3 concentration, because in most previous studies, acute treatments, involving high O3 dosages, were applied. Possible roles of the cloned sequences in the response of P. latifolia to O3 and other causes of oxidative stress are discussed.
RFLP, RAPD, STS and DDRT-PCR techniques were applied to find molecular markers linked to Pm13, an Aegilops longissima gene conferring resistance to powdery mildew in wheat. The experimental strategy ...was based on the differential comparison of DNAs from common wheat and from common wheat/Ae. longissima recombinant lines carrying short segments of the 3S'S chromosome arm containing the Pm13 gene. Sixteen RFLP clones that detect loci previously located in the short arms of group-3 wheat chromosomes were screened for their ability to hybridise to Ae. longissima restriction fragments derived from the 3S'S segments introgressed into the recombinant lines. Eight RFLP clones and one STS marker detected 3S'S-specific fragments whose location relative to the wheat-alien chromatin breakage point of the recombinant lines was determined. Four amplification products were identified through the screening of about 200 RAPD primers. Their polymorphism was associated with the introgression of the alien DNA. One of the differential fragments was derived from the 3S'S DNA segment, while the remaining three corresponded to the replaced 3DS DNA. Further analyses carried out using 40 combinations of DRT-PCR primers detected an additional reproducible polymorphism associated with the presence of 3S'S DNA. In view of their possible utilisation in Pm13 marker-assisted selection. differentially amplified RAPD and DDRT-PCR fragments were cloned, transformed into RFLP markers and converted into STS markers.
Low-molecular-weight glutenin subunits (LMW-GSs) are wheat endosperm proteins mostly encoded by genes located at the Glu-3 loci. These proteins are of particular interest in durum wheat because a ...correlation between LMW-GSs encoded by genes at the Glu-B3 locus and the pasta-making quality of durum wheat semolina has been shown. We isolated and characterized two allelic lmw-gs genes located at the Glu-B3 locus and present in durum wheat lines displaying different qualitative properties. The clones pLMW1CL and lambda LMW3.1 were found to contain allelic sequences encoding LMW-GSs belonging to the good and poor quality-related groups named LMW-2 and LMW-1, respectively. The LMW-GSs specified by these genes have very large repetitive domains which are composed of repeats regularly distributed along the domain. The main difference between these two proteins is an insertion of 13 amino acids within the repetitive domain which, by itself, seems insufficient to explain the qualitative differences between LMW-2 and LMW-1. These results further support the hypothesis that the greater amount of LMW-2, rather than sequence peculiarities, accounts for the better quality observed in durum wheat cultivars possessing these subunits. The characterization of the complete primary structure of these alleles, other than providing information for an understanding of the structure-function relationship among LMW-GSs and furnishing basic material for wheat engineering, should also assist in our understanding of the evolutionary relationship between the different lmw-gs genes.
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