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1

Physical mapping resources for large plant genomes: radiation hybrids for wheat D-genome progenitor Aegilops tauschii  

PubMed Central

Background Development of a high quality reference sequence is a daunting task in crops like wheat with large (~17Gb), highly repetitive (>80%) and polyploid genome. To achieve complete sequence assembly of such genomes, development of a high quality physical map is a necessary first step. However, due to the lack of recombination in certain regions of the chromosomes, genetic mapping, which uses recombination frequency to map marker loci, alone is not sufficient to develop high quality marker scaffolds for a sequence ready physical map. Radiation hybrid (RH) mapping, which uses radiation induced chromosomal breaks, has proven to be a successful approach for developing marker scaffolds for sequence assembly in animal systems. Here, the development and characterization of a RH panel for the mapping of D-genome of wheat progenitor Aegilops tauschii is reported. Results Radiation dosages of 350 and 450 Gy were optimized for seed irradiation of a synthetic hexaploid (AABBDD) wheat with the D-genome of Ae. tauschii accession AL8/78. The surviving plants after irradiation were crossed to durum wheat (AABB), to produce pentaploid RH1s (AABBD), which allows the simultaneous mapping of the whole D-genome. A panel of 1,510 RH1 plants was obtained, of which 592 plants were generated from the mature RH1 seeds, and 918 plants were rescued through embryo culture due to poor germination (<3%) of mature RH1 seeds. This panel showed a homogenous marker loss (2.1%) after screening with SSR markers uniformly covering all the D-genome chromosomes. Different marker systems mostly detected different lines with deletions. Using markers covering known distances, the mapping resolution of this RH panel was estimated to be <140kb. Analysis of only 16 RH lines carrying deletions on chromosome 2D resulted in a physical map with cM/cR ratio of 1:5.2 and 15 distinct bins. Additionally, with this small set of lines, almost all the tested ESTs could be mapped. A set of 399 most informative RH lines with an average deletion frequency of ~10% were identified for developing high density marker scaffolds of the D-genome. Conclusions The RH panel reported here is the first developed for any wild ancestor of a major cultivated plant species. The results provided insight into various aspects of RH mapping in plants, including the genetically effective cell number for wheat (for the first time) and the potential implementation of this technique in other plant species. This RH panel will be an invaluable resource for mapping gene based markers, developing a complete marker scaffold for the whole genome sequence assembly, fine mapping of markers and functional characterization of genes and gene networks present on the D-genome. PMID:23127207

2012-01-01

2

Aegilops tauschii single nucleotide polymorphisms shed light on the origins of wheat D-genome genetic diversity and pinpoint the geographic origin of hexaploid wheat.  

PubMed

Hexaploid wheat (Triticum aestivum, genomes AABBDD) originated by hybridization of tetraploid Triticum turgidum (genomes AABB) with Aegilops tauschii (genomes DD). Genetic relationships between A. tauschii and the wheat D genome are of central importance for the understanding of wheat origin and subsequent evolution. Genetic relationships among 477 A. tauschii and wheat accessions were studied with the A. tauschii 10K Infinium single nucleotide polymorphism (SNP) array. Aegilops tauschii consists of two lineages (designated 1 and 2) having little genetic contact. Each lineage consists of two closely related sublineages. A population within lineage 2 in the southwestern and southern Caspian appears to be the main source of the wheat D genome. Lineage 1 contributed as little as 0.8% of the wheat D genome. Triticum aestivum is subdivided into the western and Far Eastern populations. The Far Eastern population conserved the genetic make-up of the nascent T. aestivum more than the western population. In wheat, diversity is high in chromosomes 1D and 2D and it correlates in all wheat D-genome and A. tauschii chromosomes with recombination rates. Gene flow from A. tauschii was an important source of wheat genetic diversity and shaped its distribution along the D-genome chromosomes. PMID:23374069

Wang, Jirui; Luo, Ming-Cheng; Chen, Zhongxu; You, Frank M; Wei, Yuming; Zheng, Youliang; Dvorak, Jan

2013-05-01

3

Draft genome of the wheat A-genome progenitor Triticum urartu.  

PubMed

Bread wheat (Triticum aestivum, AABBDD) is one of the most widely cultivated and consumed food crops in the world. However, the complex polyploid nature of its genome makes genetic and functional analyses extremely challenging. The A?genome, as a basic genome of bread wheat and other polyploid wheats, for example, T. turgidum (AABB), T. timopheevii (AAGG) and T. zhukovskyi (AAGGA(m)A(m)), is central to wheat evolution, domestication and genetic improvement. The progenitor species of the A?genome is the diploid wild einkorn wheat T.?urartu, which resembles cultivated wheat more extensively than do Aegilops speltoides (the ancestor of the B genome) and Ae. tauschii (the donor of the D genome), especially in the morphology and development of spike and seed. Here we present the generation, assembly and analysis of a whole-genome shotgun draft sequence of the T.?urartu genome. We identified protein-coding gene models, performed genome structure analyses and assessed its utility for analysing agronomically important genes and for developing molecular markers. Our T.?urartu genome assembly provides a diploid reference for analysis of polyploid wheat genomes and is a valuable resource for the genetic improvement of wheat. PMID:23535596

Ling, Hong-Qing; Zhao, Shancen; Liu, Dongcheng; Wang, Junyi; Sun, Hua; Zhang, Chi; Fan, Huajie; Li, Dong; Dong, Lingli; Tao, Yong; Gao, Chuan; Wu, Huilan; Li, Yiwen; Cui, Yan; Guo, Xiaosen; Zheng, Shusong; Wang, Biao; Yu, Kang; Liang, Qinsi; Yang, Wenlong; Lou, Xueyuan; Chen, Jie; Feng, Mingji; Jian, Jianbo; Zhang, Xiaofei; Luo, Guangbin; Jiang, Ying; Liu, Junjie; Wang, Zhaobao; Sha, Yuhui; Zhang, Bairu; Wu, Huajun; Tang, Dingzhong; Shen, Qianhua; Xue, Pengya; Zou, Shenhao; Wang, Xiujie; Liu, Xin; Wang, Famin; Yang, Yanping; An, Xueli; Dong, Zhenying; Zhang, Kunpu; Zhang, Xiangqi; Luo, Ming-Cheng; Dvorak, Jan; Tong, Yiping; Wang, Jian; Yang, Huanming; Li, Zhensheng; Wang, Daowen; Zhang, Aimin; Wang, Jun

2013-04-01

4

Identification of quantitative trait loci for abscisic acid responsiveness in the D-genome of hexaploid wheat.  

PubMed

In crop species such as wheat, abiotic stresses and preharvest sprouting reduce grain yield and quality. The plant hormone abscisic acid (ABA) plays important roles in abiotic stress tolerance and seed dormancy. In previous studies, we evaluated ABA responsiveness of 67 Aegilops tauschii accessions and their synthetic hexaploid wheat lines, finding wide variation that was due to the D-genome. In this study, quantitative trait locus (QTL) analysis was performed using an F2 population derived from crosses of highly ABA-responsive and less-responsive synthetic wheat lines. A significant QTL was detected on chromosome 6D, in a similar location to that reported for ABA responsiveness using recombinant inbred lines derived from common wheat cultivars Mironovskaya 808 and Chinese Spring. A comparative map and physiological and expression analyses of the 6D QTL suggested that this locus involved in line differences among wheat synthetics is different from that involved in cultivar differences in common wheat. The common wheat 6D QTL was found to affect seed dormancy and the regulation of cold-responsive/late embryogenesis abundant genes during dehydration. However, in synthetic wheat, we failed to detect any association of ABA responsiveness with abiotic stress tolerance or seed dormancy, at least under our experimental conditions. Development of near-isogenic lines will be important for functional analyses of the synthetic wheat 6D QTL. PMID:24877675

Iehisa, Julio C M; Matsuura, Takakazu; Mori, Izumi C; Yokota, Hirokazu; Kobayashi, Fuminori; Takumi, Shigeo

2014-06-15

5

Genetic and physiological architecture of early vigor in Aegilops tauschii, the D-genome of hexaploid wheat. A quantitative trait loci analysis  

Microsoft Academic Search

Plant growth can be studied at different organizational levels, varying from cell, leaf, and shoot to the whole plant. The early growth of seedlings is important for the plant's establishment and its eventual success. Wheat (Triticum aestivum, genome AABBDD) seedlings exhibit a low early growth rate or early vigor. The germplasm of wheat is limited. Wild relatives constitute a source

Steege ter M. W; Ouden den F. M; H. Lambers; P. Stam; A. J. M. Peeters

2005-01-01

6

Genetic and Physiological Architecture of Early Vigor in Aegilops tauschii, the D-Genome Donor of Hexaploid Wheat. A Quantitative Trait Loci Analysis1(w)  

Microsoft Academic Search

Plant growth can be studied at different organizational levels, varying from cell, leaf, and shoot to the whole plant. The early growth of seedlings is important for the plant's establishment and its eventual success. Wheat (Triticum aestivum, genome AABBDD) seedlings exhibit a low early growth rate or early vigor. The germplasm of wheat is limited. Wild relatives constitute a source

Franka M. den Ouden; Hans Lambers; Piet Stam; Anton J. M. Peeters

7

Prevalence of gene expression additivity in genetically stable wheat allohexaploids.  

PubMed

The reprogramming of gene expression appears as the major trend in synthetic and natural allopolyploids where expression of an important proportion of genes was shown to deviate from that of the parents or the average of the parents. In this study, we analyzed gene expression changes in previously reported, highly stable synthetic wheat allohexaploids that combine the D genome of Aegilops tauschii and the AB genome extracted from the natural hexaploid wheat Triticum aestivum. A comprehensive genome-wide analysis of transcriptional changes using the Affymetrix GeneChip Wheat Genome Array was conducted. Prevalence of gene expression additivity was observed where expression does not deviate from the average of the parents for 99.3% of 34,820 expressed transcripts. Moreover, nearly similar expression was observed (for 99.5% of genes) when comparing these synthetic and natural wheat allohexaploids. Such near-complete additivity has never been reported for other allopolyploids and, more interestingly, for other synthetic wheat allohexaploids that differ from the ones studied here by having the natural tetraploid Triticum turgidum as the AB genome progenitor. Our study gave insights into the dynamics of additive gene expression in the highly stable wheat allohexaploids. PMID:23278496

Chelaifa, Houda; Chagué, Véronique; Chalabi, Smahane; Mestiri, Imen; Arnaud, Dominique; Deffains, Denise; Lu, Yunhai; Belcram, Harry; Huteau, Virginie; Chiquet, Julien; Coriton, Olivier; Just, Jérémy; Jahier, Joseph; Chalhoub, Boulos

2013-02-01

8

Identification of transposons, retroelements, and a gene family predominantly expressed in floral tissues in chromosome 3DS of the hexaploid wheat progenitor Aegilops tauschii  

Microsoft Academic Search

A multigene family expressed during early floral development was identified on the short arm of wheat chromosome 3D in the region of the Ph2 locus, a locus controlling homoeologous chromosome pairing in allohexaploid wheat. Physical, genetic and molecular characterisation of the Wheat\\u000a Meiosis 1 (WM1) gene family identified seven members that localised within a region of 173-kb. WM1 gene family

Ryan Whitford; Ute Baumann; Tim Sutton; Luke Gumaelius; Petra Wolters; Scott Tingey; Jason A. Able; Peter Langridge

2007-01-01

9

Map-based analysis of the tenacious glume gene Tg-B1 of wild emmer and its role in wheat domestication.  

PubMed

The domestication of wheat was instrumental in spawning the civilization of humankind, and it occurred through genetic mutations that gave rise to types with non-fragile rachises, soft glumes, and free-threshing seed. Wild emmer (Triticum turgidum ssp. dicoccoides), the tetraploid AB-genome progenitor of domesticated wheat has genes that confer tenacious glumes (Tg) that underwent genetic mutations to give rise to free-threshing wheat. Here, we evaluated disomic substitution lines involving chromosomes 2A and 2B of wild emmer accessions substituted for homologous chromosomes in tetraploid and hexaploid backgrounds. The results suggested that both chromosomes 2A and 2B of wild emmer possess genes that inhibit threshability. A population of recombinant inbred lines derived from the tetraploid durum wheat variety Langdon crossed with a Langdon - T. turgidum ssp. dicoccoides accession PI 481521 chromosome 2B disomic substitution line was used to develop a genetic linkage map of 2B, evaluate the genetics of threshability, and map the gene derived from PI 481521 that inhibited threshability. A 2BS linkage map comprised of 58 markers was developed, and markers delineated the gene to a 2.3 cM interval. Comparative analysis with maps containing the tenacious glume gene Tg-D1 on chromosome arm 2 DS from Aegilops tauschii, the D genome progenitor of hexaploid wheat, revealed that the gene inhibiting threshability in wild emmer was homoeologous to Tg-D1 and therefore designated Tg-B1. Comparative analysis with rice and Brachypodium distachyon indicated a high level of divergence and poorly conserved colinearity, particularly near the Tg-B1 locus. These results provide a foundation for further studies involving Tg-B1, which, together with Tg-D1, had profound influences on wheat domestication. PMID:24657062

Faris, Justin D; Zhang, Zengcui; Chao, Shiaoman

2014-06-01

10

mRNA and Small RNA Transcriptomes Reveal Insights into Dynamic Homoeolog Regulation of Allopolyploid Heterosis in Nascent Hexaploid Wheat[W][OPEN  

PubMed Central

Nascent allohexaploid wheat may represent the initial genetic state of common wheat (Triticum aestivum), which arose as a hybrid between Triticum turgidum (AABB) and Aegilops tauschii (DD) and by chromosome doubling and outcompeted its parents in growth vigor and adaptability. To better understand the molecular basis for this success, we performed mRNA and small RNA transcriptome analyses in nascent allohexaploid wheat and its following generations, their progenitors, and the natural allohexaploid cultivar Chinese Spring, with the assistance of recently published A and D genome sequences. We found that nonadditively expressed protein-coding genes were rare but relevant to growth vigor. Moreover, a high proportion of protein-coding genes exhibited parental expression level dominance, with genes for which the total homoeolog expression level in the progeny was similar to that in T. turgidum potentially participating in development and those with similar expression to that in Ae. tauschii involved in adaptation. In addition, a high proportion of microRNAs showed nonadditive expression upon polyploidization, potentially leading to differential expression of important target genes. Furthermore, increased small interfering RNA density was observed for transposable element–associated D homoeologs in the allohexaploid progeny, which may account for biased repression of D homoeologs. Together, our data provide insights into small RNA–mediated dynamic homoeolog regulation mechanisms that may contribute to heterosis in nascent hexaploid wheat. PMID:24838975

Li, Aili; Liu, Dengcai; Wu, Jun; Zhao, Xubo; Hao, Ming; Geng, Shuaifeng; Yan, Jun; Jiang, Xiaoxue; Zhang, Lianquan; Wu, Junyan; Yin, Lingjie; Zhang, Rongzhi; Wu, Liang; Zheng, Youliang; Mao, Long

2014-01-01

11

Wheat Allergy  

MedlinePLUS

Wheat Allergy Wheat allergy is most common in children, and is usually outgrown before reaching adulthood, often by age ... you are trying to achieve. Differences between Wheat Allergy and Celiac Disease or Gluten Intolerance A wheat ...

12

New insights into the origin of the B genome of hexaploid wheat: Evolutionary relationships at the SPA genomic region with the S genome of the diploid relative Aegilops speltoides  

PubMed Central

Background Several studies suggested that the diploid ancestor of the B genome of tetraploid and hexaploid wheat species belongs to the Sitopsis section, having Aegilops speltoides (SS, 2n = 14) as the closest identified relative. However molecular relationships based on genomic sequence comparison, including both coding and non-coding DNA, have never been investigated. In an attempt to clarify these relationships, we compared, in this study, sequences of the Storage Protein Activator (SPA) locus region of the S genome of Ae. speltoides (2n = 14) to that of the A, B and D genomes co-resident in the hexaploid wheat species (Triticum aestivum, AABBDD, 2n = 42). Results Four BAC clones, spanning the SPA locus of respectively the A, B, D and S genomes, were isolated and sequenced. Orthologous genomic regions were identified as delimited by shared non-transposable elements and non-coding sequences surrounding the SPA gene and correspond to 35 268, 22 739, 43 397 and 53 919 bp for the A, B, D and S genomes, respectively. Sequence length discrepancies within and outside the SPA orthologous regions are the result of non-shared transposable elements (TE) insertions, all of which inserted after the progenitors of the four genomes divergence. Conclusion On the basis of conserved sequence length as well as identity of the shared non-TE regions and the SPA coding sequence, Ae speltoides appears to be more evolutionary related to the B genome of T. aestivum than the A and D genomes. However, the differential insertions of TEs, none of which are conserved between the two genomes led to the conclusion that the S genome of Ae. speltoides has diverged very early from the progenitor of the B genome which remains to be identified. PMID:19032732

Salse, Jérome; Chagué, Véronique; Bolot, Stéphanie; Magdelenat, Ghislaine; Huneau, Cécile; Pont, Caroline; Belcram, Harry; Couloux, Arnaud; Gardais, Soazic; Evrard, Aurélie; Segurens, Béatrice; Charles, Mathieu; Ravel, Catherine; Samain, Sylvie; Charmet, Gilles; Boudet, Nathalie; Chalhoub, Boulos

2008-01-01

13

A reconsideration of the domestication geography of tetraploid wheats  

Microsoft Academic Search

The domestication of tetraploid wheats started from their wild progenitor Triticum dicoccoides. In this paper, the geographical distribution of this progenitor is revised to include more sampling locations. The paper is based on a collection of wild and domesticated lines (226 accessions in total) analyzed by AFLP at 169 polymorphic loci. The collection includes the 69 wild lines considered by

H. Ozkan; A. Brandolini; C. Pozzi; S. Effgen; J. Wunder; F. Salamini

2005-01-01

14

Structures of the three homoeologous loci of wheat benzoxazinone biosynthetic genes TaBx3 and TaBx4 and characterization of their promoter sequences.  

PubMed

Common wheat (2n=6x=42, genome formula AABBDD) accumulates benzoxazinones (Bxs) as defensive compounds. There are five Bx biosynthetic genes (TaBx1-TaBx5), and their homoeologous alleles are located on all three homoeologous chromosomes of the A, B and D genomes. Here the molecular structures of the TaBx3 and TaBx4 loci, both of which are located on chromosomes 5A, 5B and 5D, were revealed by sequencing transformation-competent artificial chromosome (TAC) clones. In all homoeologous chromosomes, TaBx3 existed downstream of TaBx4 in a tail-to-head manner, and the two genes were separated from each other by 9.0 kb in 5A, 7.3 kb in 5B and 11.3 kb in 5D. Among the three homoeologs of TaBx3 and TaBx4, the promoter sequences were less conserved than the coding sequences. The promoter sequences of TaBx3 and TaBx4 were highly similar to those of their respective orthologs in the diploid progenitors of common wheat, but were not similar to those of the maize orthologs. Sequence similarity was found between the TaBx3 and TaBx4 coding sequences, but not between their promoter sequences despite their similar transcription pattern at the seedling stage. Some putative cis-elements were found to be shared by all TaBx3 and TaBx4 promoter regions. These results imply that stage-specific transcription of TaBx3 and TaBx4 is not controlled by global sequence similarity of their promoters but by some essential cis-elements. The promoter activity measured by transient assays in wheat protoplasts was similar among the three homoeologs of TaBx3 and TaBx4 in spite of their differential transcript levels in wheat seedlings. PMID:18040657

Nomura, Taiji; Nasuda, Shuhei; Kawaura, Kanako; Ogihara, Yasunari; Kato, Nobuhiko; Sato, Fumihiko; Kojima, Toshio; Toyoda, Atsushi; Iwamura, Hajime; Endo, Takashi R

2008-02-01

15

Agricultural Genotyping RAPiD Genomics is a DNA genotyping and genetic data analysis company providing tools for  

E-print Network

Agricultural Genotyping RAPiD Genomics is a DNA genotyping and genetic data analysis company or animal even before the seed germinates or the animal is born. The system developed by RAPiD Genomics in parallel, at a cost of several hundred dollars per sample. RAPiD Genomics has short- ened this process

Jawitz, James W.

16

Acc homoeoloci and the evolution of wheat genomes  

PubMed Central

The DNA sequences of wheat Acc-1 and Acc-2 loci, encoding the plastid and cytosolic forms of the enzyme acetyl-CoA carboxylase, were analyzed with a view to understanding the evolution of these genes and the origin of the three genomes in modern hexaploid wheat. Acc-1 and Acc-2 loci from each of the wheats Triticum urartu (A genome), Aegilops tauschii (D genome), Triticum turgidum (AB genome), and Triticum aestivum (ABD genome), as well as two Acc-2-related pseudogenes from T. urartu were sequenced. The 2.3–2.4 Mya divergence time calculated here for the three homoeologous chromosomes, on the basis of coding and intron sequences of the Acc-1 genes, is at the low end of other estimates. Our clock was calibrated by using 60 Mya for the divergence between wheat and maize. On the same time scale, wheat and barley diverged 11.6 Mya, based on sequences of Acc and other genes. The regions flanking the Acc genes are not conserved among the A, B, and D genomes. They are conserved when comparing homoeologous genomes of diploid, tetraploid, and hexaploid wheats. Substitution rates in intergenic regions consisting primarily of repetitive sequences vary substantially along the loci and on average are 3.5-fold higher than the Acc intron substitution rates. The composition of the Acc homoeoloci suggests haplotype divergence exceeding in some cases 0.5 Mya. Such variation might result in a significant overestimate of the time since tetraploid wheat formation, which occurred no more than 0.5 Mya. PMID:18599450

Chalupska, D.; Lee, H. Y.; Faris, J. D.; Evrard, A.; Chalhoub, B.; Haselkorn, R.; Gornicki, P.

2008-01-01

17

The Crab Nebula's progenitor  

NASA Technical Reports Server (NTRS)

The initial mass of the Crab Nebula's progenitor star is estimated by comparing the observed nebular chemical abundances with detailed evolutionary calculations for 2.4- and 2.6-solar-mass helium cores of stars with masses of 8 to 10 solar masses. The results indicate that the mass of the Crab's progenitor was between the upper limit of about 8 solar masses for carbon deflagration and the lower limit of about 9.5 solar masses set by the dredge-up of the helium layer before the development of the helium-burning convective region. A scenario is outlined for the evolution of the progenitor star. It is suggested that the Crab Nebula was probably the product of an electron-capture supernova.

Nomoto, K.; Sugimoto, D.; Sparks, W. M.; Fesen, R. A.; Gull, T. R.; Miyaji, S.

1982-01-01

18

Physical mapping of wheat aquaporin genes.  

PubMed

Aquaporins are water channel proteins that control the flow of water across cellular membranes and play vital roles in all aspects of plant-water relations. Our previous identification of 35 wheat PIP and TIP aquaporin genes showed they formed a large family with many conserved features that are thought to be important in structure and function. The present work focussed on determining the positions of these genes in the wheat genome in order to help investigate their functions in water uptake and transport. Genomic locations of wheat PIPs and TIPs were predicted using a number of reported rice-wheat comparative maps and additional in silico approaches. Physical mapping of select genes utilising aneuploid stocks and progenitor DNAs placed these on chromosomes 2B, 2D, 6B and 7B and helped to clarify the individual genes and homoeologues. The compilation of all in silico and physical mapping work confirmed many of the orthologous relationships between wheat and rice and/or barley genes, and synteny in the related areas of genome. These results further reinforce that wheat PIP and TIP proteins are most likely to have similar functions to those closely related in rice, including water permeability and abiotic stress response, and provide important tools for future investigations into the involvement of this complex gene family in traits related to plant-water relations and osmotic stress response. PMID:19924390

Forrest, Kerrie L; Bhave, Mrinal

2010-02-01

19

Spring Wheat Breeding  

Microsoft Academic Search

Wheat (various species of the genus Triticum) is a grass originating from the Levant area of the Middle East. However, only hexaploid common wheat (Triticum eastivum), and tetraploid durum wheat (Triticum turgidum ssp. durum) are presently cultivated worldwide. Not only is wheat an important crop today, it may well have influenced human history.\\u000a Wheat was a key factor enabling the

M. Mergoum; P. K. Singh; J. A. Anderson; R. J. Peña; R. P. Singh; S. S. Xu; J. K. Ransom

20

Rapid Elimination of Low-Copy DNA Sequences in Polyploid Wheat: A Possible Mechanism for Differentiation of Homoeologous Chromosomes  

PubMed Central

To study genome evolution in allopolyploid plants, we analyzed polyploid wheats and their diploid progenitors for the occurrence of 16 low-copy chromosome- or genome-specific sequences isolated from hexaploid wheat. Based on their occurrence in the diploid species, we classified the sequences into two groups: group I, found in only one of the three diploid progenitors of hexaploid wheat, and group II, found in all three diploid progenitors. The absence of group II sequences from one genome of tetraploid wheat and from two genomes of hexaploid wheat indicates their specific elimination from these genomes at the polyploid level. Analysis of a newly synthesized amphiploid, having a genomic constitution analogous to that of hexaploid wheat, revealed a pattern of sequence elimination similar to the one found in hexaploid wheat. Apparently, speciation through allopolyploidy is accompanied by a rapid, nonrandom elimination of specific, low-copy, probably noncoding DNA sequences at the early stages of allopolyploidization, resulting in further divergence of homoeologous chromosomes (partially homologous chromosomes of different genomes carrying the same order of gene loci). We suggest that such genomic changes may provide the physical basis for the diploid-like meiotic behavior of polyploid wheat. PMID:9383078

Feldman, M.; Liu, B.; Segal, G.; Abbo, S.; Levy, A. A.; Vega, J. M.

1997-01-01

21

Single-copy genes define a conserved order between rice and wheat for understanding differences caused by duplication, deletion, and transposition of genes  

Microsoft Academic Search

The high-quality rice genome sequence is serving as a reference for comparative genome analysis in crop plants, especially cereals. However, early comparisons with bread wheat showed complex patterns of conserved synteny (gene content) and colinearity (gene order). Here, we show the presence of ancient duplicated segments in the progenitor of wheat, which were first identified in the rice genome. We

Nagendra K. Singh; Vivek Dalal; Kamlesh Batra; Binay K. Singh; G. Chitra; Archana Singh; Irfan A. Ghazi; Mahavir Yadav; Awadhesh Pandit; Rekha Dixit; Pradeep K. Singh; Harvinder Singh; Kirpa R. Koundal; Kishor Gaikwad; Trilochan Mohapatra; Tilak R. Sharma

2007-01-01

22

SNP and haplotype identification of the wheat monomeric ?-amylase inhibitor genes  

Microsoft Academic Search

Seventy-three gene sequences encoding monomeric ?-amylase inhibitors were characterized from cultivated wheat “Chinese Spring”,\\u000a group 6 nullisomic-tetrasomic lines of “Chinese Spring” and diploid putative progenitors of common wheat. The monomeric ?-amylase\\u000a inhibitors from the different sources shared very high homology (99.54%). The different ?-amylase inhibitors, which were determined\\u000a by the 24 single nucleotide polymorphisms (SNPs) of their gene sequences, were

Ji-Rui Wang; Yu-Ming Wei; Ze-Hong Yan; You-Liang Zheng

2008-01-01

23

Overexpression of a Wheat CCaMK Gene Reduces ABA Sensitivity of Arabidopsis thaliana During Seed Germination and Seedling Growth  

Microsoft Academic Search

Abscisic acid (ABA) plays pivotal roles in plant biotic and abiotic stress responses, where calcium ions are important second\\u000a messengers. Calcium\\/calmodulin-dependent protein kinase (CCaMK) is essential for nodulation in legumes, but whether it will\\u000a perceive calcium signals from abiotic stresses is not clear, especially in non-legume plants. Here we report the isolation\\u000a and characterization of the D-genome copy of wheat

Cui Yang; Aili Li; Yongliang Zhao; Zenglin Zhang; Yuanfang Zhu; Xiaomei Tan; Shuaifeng Geng; Hanzi Guo; Xueyong Zhang; Zhensheng Kang; Long Mao

2011-01-01

24

Discrimination of the closely related A and D genomes of the hexaploid oat Avena sativa L.  

PubMed Central

A satellite DNA sequence, As120a, specific to the A-genome chromosomes in the hexaploid oat, Avena sativa L., was isolated by subcloning a fragment with internal tandem repeats from a plasmid, pAs120, that had been obtained from an Avena strigosa (As genome) genomic library. Southern and in situ hybridization showed that sequences with homology to sequences within pAs120 were dispersed throughout the genome of diploid (A and C genomes), tetraploid (AC genomes), and hexaploid (ACD genomes) Avena species. In contrast, sequences homologous to As120a were found in two A-genome species (A. strigosa and Avena longiglumis) and in the hexaploid A. sativa whereas this sequence was little amplified in the tetraploid Avena murphyi and was absent in the remaining A- and C-genome diploid species. In situ hybridization of pAs120a to hexaploid oat species revealed the distribution of elements of the As120a repeated family over both arms of 14 of 42 chromosomes of this species. By using double in situ hybridization with pAs120a and a C genome-specific probe, three sets of 14 chromosomes were revealed corresponding to the A, C, and D genomes of the hexaploid species. Simultaneous in situ hybridizations with pAs120a and ribosomal probes were used to assign the SAT chromosomes of hexaploid species to their correct genomes. This work reports a sequence able to distinguish between the closely related A and D genomes of hexaploid oats. This sequence offers new opportunities to analyze the relationships of Avena species and to explore the possible evolution of various polyploid oat species. PMID:9770506

Linares, Concha; Ferrer, Esther; Fominaya, Araceli

1998-01-01

25

Wheat grass selection  

NSDL National Science Digital Library

The wheat grass on the right is not tolerant of high salinity, or high salt conditions. The wheat grass on the left is a hybrid that has a high salt tolerance. It grows well in high salinity environments.

Richard Wang (USDA;ARS)

2006-09-25

26

Wheat Diseases Atlas.  

E-print Network

small grains by clean cultivation and crop rotation. 4 Crown rot with decay at base of stalk Plant Parasitic Nematodes (Nematodes - Cyst, Root Knot, Root Lesion, Seed Gall, Stunt and others) Plant parasitic nematodes are nonsegmented roundworms... that mostly inhabit the soil and feed on roots of wheat and other plants. However, one species, called the wheat seed gall nematode, Anguina tritici, is a significant pathogen of wheat. It is detected on threshed wheat by the presence of galls and hard...

McCoy, Norman L.; Berry, Robert W.

1982-01-01

27

Wheat Streak Mosaic Virus  

E-print Network

Virus First discovered in Nebraska in 1922, wheat streak mosaic virus (WSMV) remains a threat today across most of the U.S. Central Plains. WSMV affects spring wheat, barley, corn, triticale, rye and numerous other annual and perennial grasses... Virus First discovered in Nebraska in 1922, wheat streak mosaic virus (WSMV) remains a threat today across most of the U.S. Central Plains. WSMV affects spring wheat, barley, corn, triticale, rye and numerous other annual and perennial grasses...

Morgan, Gaylon

2005-01-26

28

Invisible Coatings for Wheat Kernels  

Microsoft Academic Search

Cereal Chem. 79(6):857-860 It is occasionally necessary to tag wheat kernels without altering their appearance. Coatings have potential applications to tag wheat of a particular color or protein class, diseased wheat such as Karnal bunt, or genetically modified wheat. This methodology will aid in development of cali- brations for sorting instruments. Procedures were developed to coat wheat kernels with invisible

M. S. Ram; Floyd E. Dowell; Larry Seitz

2002-01-01

29

Production and identification of wheat-Agropyron cristatum 6P translocation lines.  

PubMed

The narrow genetic background of wheat is the primary factor that has restricted the improvement of crop yield in recent years. The kernel number per spike is the most important factor of the many potential characteristics that determine wheat yield. Agropyron cristatum (L.) Gaertn., a wild relative of wheat, has the characteristics of superior numbers of florets and kernels per spike, which are controlled by chromosome 6P. In this study, the wheat-A. cristatum disomic addition and substitution lines were used as bridge materials to produce wheat-A. cristatum 6P translocation lines induced by gametocidal chromosomes and irradiation. The results of genomic in situ hybridization showed that the frequency of translocation induced by gametocidal chromosomes was 5.08%, which was higher than the frequency of irradiated hybrids (2.78%) and irradiated pollen (2.12%). The fluorescence in situ hybridization results of the translocation lines showed that A. cristatum chromosome 6P could be translocated to wheat ABD genome, and the recombination frequency was A genome > B genome > D genome. The alien A. cristatum chromosome 6P was translocated to wheat homoeologous groups 1, 2, 3, 5 and 6. We obtained abundant translocation lines that possessed whole-arm, terminal, segmental and intercalary translocations. Three 6PS-specific and four 6PL-specific markers will be useful to rapidly identify and trace the translocated fragments. The different wheat-A. cristatum 6P translocation lines obtained in this study can provide basic materials for analyzing the alien genes carried by chromosome 6P. The translocation line WAT33-1-3 and introgression lines WAI37-2 and WAI41-1, which had significant characteristics of multikernel (high numbers of kernels per spike), could be utilized as novel germplasms for high-yield wheat breeding. PMID:20490543

Luan, Yang; Wang, Xiaoguang; Liu, Weihua; Li, Chunye; Zhang, Jinpeng; Gao, Ainong; Wang, Yandong; Yang, Xinming; Li, Lihui

2010-07-01

30

The Progenitors of Thermonuclear Supernovae  

SciTech Connect

In the framework of the rotating Double Degenerate Scenario for type Ia Supernovae progenitors, we show that the dichotomy between explosive events in early and late type galaxies can be easily explained. Assuming that more massive progenitors produce slow-decline (high-luminosity) light curve, it comes out that, at the current age of the Universe, in late type galaxies the continuous star formation provides very massive exploding objects (prompt component) corresponding to slow-decline (bright) SNe; on the other hand, in early type galaxies, where star formation ended many billions years ago, only low mass ''normal luminosity'' objects (delayed component) are present.

Piersanti, L.; Straniero, O. [INAF-OACTe via M. Maggini, snc., 64100 Teramo (Italy); Tornambe, A. [OAR-via di Frascati, 33, 00040 Monte Porzio Catone (Italy) (Italy); Dominguez, I. [Depto. Fysica Teorica y del Cosmos, Univ. Granada (Spain)

2009-05-03

31

Neural progenitors from human embryonic stem cells  

Microsoft Academic Search

The derivation of neural progenitor cells from human embryonic stem (ES) cells is of value both in the study of early human neurogenesis and in the creation of an unlimited source of donor cells for neural transplantation therapy. Here we report the generation of enriched and expandable preparations of proliferating neural progenitors from human ES cells. The neural progenitors could

Pavel Itsykson; Tikva Turetsky; Martin F. Pera; Etti Reinhartz; Anna Itzik; Tamir Ben-Hur; Benjamin E. Reubinoff

2001-01-01

32

The origin of the B-genome of bread wheat (Triticum aestivum L.).  

PubMed

Understanding the origin of cultivated wheats would further their genetic improvement. The hexaploid bread wheat (Triticum aestivum L., AABBDD) is believed to have originated through one or more rare hybridization events between Aegilops tauschii (DD) and the tetraploid T. turgidum (AABB). Progenitor of the A-genome of the tetraploid and hexaploid wheats has generally been accepted to be T. urartu. In spite of the large number of attempts and published reports about the origin of the B-genome in cultivated wheats, the donor of the B-genome is still relatively unknown and controversial and, hence, remains open. This genome has been found to be closely related to the S-genome of the Sitopsis section (Ae. speltoides, Ae. longissima, Ae. sharonensis, Ae. searsii, and Ae. bicornis) of the genus Aegilops L. Among Sitopsis species, the most positive evidence has been accumulated for Ae. speltoides as the progenitor of the B-genome. Therefore, one or more of the Sitopsis species were proposed frequently as the B-genome donor. Although several reviews have been written on the origin of the genomes of wheat over the years, this paper will attempt for the first time to review the immense literature on the subject, with a particular emphasis on the B-genome which has attracted a huge attention over some 100 years. The ambiguity and conflicting results in most of the methods employed in deducing the precise B-genome donor/s to bread wheat are also discussed. PMID:23755530

Haider, N

2013-03-01

33

Wheat Production in Texas.  

E-print Network

Tascosa, are well suited to growing under these conditions. Fur- thermore, they are strong gluten wheats which will produce grain of satisfactory miliing and baking characteristics. Wheat often is grown continuously on the same land in the Rolling...~. area. Strong gluten wheats of high test rreigF' are needed for growing under irrigation becau\\r the protein content may be low if there is no4 adeauate nitrogen. Tascosa, Caprock, S'curdl I i' caddo and warrior are strong -gluten wheat. a...

Atkins, I. M.; Porter, K. B.; Merkle, O. G.; Lahr, K. A.; Gilmore, E. C.

1970-01-01

34

Population- and genome-specific patterns of linkage disequilibrium and SNP variation in spring and winter wheat (Triticum aestivum L.)  

PubMed Central

Background Single nucleotide polymorphisms (SNPs) are ideally suited for the construction of high-resolution genetic maps, studying population evolutionary history and performing genome-wide association mapping experiments. Here, we used a genome-wide set of 1536 SNPs to study linkage disequilibrium (LD) and population structure in a panel of 478 spring and winter wheat cultivars (Triticum aestivum) from 17 populations across the United States and Mexico. Results Most of the wheat oligo pool assay (OPA) SNPs that were polymorphic within the complete set of 478 cultivars were also polymorphic in all subpopulations. Higher levels of genetic differentiation were observed among wheat lines within populations than among populations. A total of nine genetically distinct clusters were identified, suggesting that some of the pre-defined populations shared significant proportion of genetic ancestry. Estimates of population structure (FST) at individual loci showed a high level of heterogeneity across the genome. In addition, seven genomic regions with elevated FST were detected between the spring and winter wheat populations. Some of these regions overlapped with previously mapped flowering time QTL. Across all populations, the highest extent of significant LD was observed in the wheat D-genome, followed by lower LD in the A- and B-genomes. The differences in the extent of LD among populations and genomes were mostly driven by differences in long-range LD ( > 10 cM). Conclusions Genome- and population-specific patterns of genetic differentiation and LD were discovered in the populations of wheat cultivars from different geographic regions. Our study demonstrated that the estimates of population structure between spring and winter wheat lines can identify genomic regions harboring candidate genes involved in the regulation of growth habit. Variation in LD suggests that breeding and selection had a different impact on each wheat genome both within and among populations. The higher extent of LD in the wheat D-genome versus the A- and B-genomes likely reflects the episodes of recent introgression and population bottleneck accompanying the origin of hexaploid wheat. The assessment of LD and population structure in this assembled panel of diverse lines provides critical information for the development of genetic resources for genome-wide association mapping of agronomically important traits in wheat. PMID:21190581

2010-01-01

35

Functional characterisation of wheat Pgip genes reveals their involvement in the local response to wounding.  

PubMed

Polygalacturonase-inhibiting proteins (PGIPs) are cell wall leucine-rich repeat (LRR) proteins involved in plant defence. The hexaploid wheat (Triticum aestivum, genome AABBDD) genome contains one Pgip gene per genome. Tapgip1 (B genome) and Tapgip2 (D genome) are expressed in all tissues, whereas Tapgip3 (A genome) is inactive because of a long terminal repeat, Copia retrotransposon insertion within the coding region. To verify whether Tapgip1 and Tapgip2 encode active PGIPs and are involved in the wheat defence response, we expressed them transiently and analysed their expression under stress conditions. Neither TaPGIP1 nor TaPGIP2 showed inhibition activity in vitro against fungal polygalacturonases. Moreover, a wheat genotype (T. turgidum ssp. dicoccoides) lacking active homologues of Tapgip1 or Tapgip2 possesses PGIP activity. At transcript level, Tapgip1 and Tapgip2 were both up-regulated after fungal infection and strongly induced following wounding. This latter result has been confirmed in transgenic wheat plants expressing the ?-glucuronidase (GUS) gene under control of the 5'-flanking region of Tdpgip1, a homologue of Tapgip1 with an identical sequence. Strong and transient GUS staining was mainly restricted to the damaged tissues and was not observed in adjacent tissues. Taken together, these results suggest that Tapgips and their homologues are involved in the wheat defence response by acting at the site of the lesion caused by pathogen infection. PMID:23574379

Janni, M; Bozzini, T; Moscetti, I; Volpi, C; D'Ovidio, R

2013-11-01

36

Cardiac Stem and Progenitor Cells  

Microsoft Academic Search

\\u000a Since the early days of cardiovascular biology, it has been believed that mammalian adult cardiomyocytes exit from the cell\\u000a cycle soon after birth, with the total number of cardiomyocytes being pre-determined. Recently, the identification of resident\\u000a cardiac stem\\/progenitor cells by several independent laboratories has challenged this long-held paradigm and has provoked\\u000a an exponential increase in the number of investigations. As

Ronglih Liao; Regina L. Sohn

37

Endothelial Progenitor Cells for Vasculogenesis  

NSDL National Science Digital Library

Postnatal vasculogenesis is considered to be involved in neovascularization of adult tissues, because bone marrow-derived endothelial progenitor cells (EPCs) were isolated from circulating mononuclear cells in peripheral blood and were shown to incorporate into sites of physiological and pathological neovascularization and to differentiate into mature endothelial cells. EPCs might have an attractive potential therapeutic application for cardiovascular ischemic diseases as a novel cell-based strategy mainly via a vasculogenesis mechanism.

Satoshi Murasawa (Kobe Institute of Biomedical Research and Innovation/RIKEN Department of Regenerative Medicine and Research); Takayuki Asahara (Tokai University School of Medicine Department of Regenerative Medicine Science)

2005-02-01

38

Three genomes differentially contribute to the biosynthesis of benzoxazinones in hexaploid wheat.  

PubMed

Hexaploid wheat (Triticum aestivum) accumulates benzoxazinones (Bxs) as defensive compounds. Previously, we found that five Bx biosynthetic genes, TaBx1-TaBx5, are located on each of the three genomes (A, B, and D) of hexaploid wheat. In this study, we isolated three homoeologous cDNAs of each TaBx gene to estimate the contribution of individual homoeologous TaBx genes to the biosynthesis of Bxs in hexaploid wheat. We analyzed their transcript levels by homoeolog- or genome-specific quantitative RT-PCR and the catalytic properties of their translation products by kinetic analyses using recombinant TaBX enzymes. The three homoeologs were transcribed differentially, and the ratio of the individual homoeologous transcripts to total homoeologous transcripts also varied with the tissue, i.e., shoots or roots, as well as with the developmental stage. Moreover, the translation products of the three homoeologs had different catalytic properties. Some TaBx homoeologs were efficiently transcribed, but the translation products showed only weak enzymatic activities, which inferred their weak contribution to Bx biosynthesis. Considering the transcript levels and the catalytic properties collectively, we concluded that the homoeologs on the B genome generally contributed the most to the Bx biosynthesis in hexaploid wheat, especially in shoots. In tetraploid wheat and the three diploid progenitors of hexaploid wheat, the respective transcript levels of the TaBx homoeologs were similar in ratio to those observed in hexaploid wheat. This result indicates that the genomic bias in the transcription of the TaBx genes in hexaploid wheat originated in the diploid progenitors and has been retained through the polyploidization. PMID:16260753

Nomura, Taiji; Ishihara, Atsushi; Yanagita, Ryo C; Endo, Takashi R; Iwamura, Hajime

2005-11-01

39

Three genomes differentially contribute to the biosynthesis of benzoxazinones in hexaploid wheat  

PubMed Central

Hexaploid wheat (Triticum aestivum) accumulates benzoxazinones (Bxs) as defensive compounds. Previously, we found that five Bx biosynthetic genes, TaBx1-TaBx5, are located on each of the three genomes (A, B, and D) of hexaploid wheat. In this study, we isolated three homoeologous cDNAs of each TaBx gene to estimate the contribution of individual homoeologous TaBx genes to the biosynthesis of Bxs in hexaploid wheat. We analyzed their transcript levels by homoeolog- or genome-specific quantitative RT-PCR and the catalytic properties of their translation products by kinetic analyses using recombinant TaBX enzymes. The three homoeologs were transcribed differentially, and the ratio of the individual homoeologous transcripts to total homoeologous transcripts also varied with the tissue, i.e., shoots or roots, as well as with the developmental stage. Moreover, the translation products of the three homoeologs had different catalytic properties. Some TaBx homoeologs were efficiently transcribed, but the translation products showed only weak enzymatic activities, which inferred their weak contribution to Bx biosynthesis. Considering the transcript levels and the catalytic properties collectively, we concluded that the homoeologs on the B genome generally contributed the most to the Bx biosynthesis in hexaploid wheat, especially in shoots. In tetraploid wheat and the three diploid progenitors of hexaploid wheat, the respective transcript levels of the TaBx homoeologs were similar in ratio to those observed in hexaploid wheat. This result indicates that the genomic bias in the transcription of the TaBx genes in hexaploid wheat originated in the diploid progenitors and has been retained through the polyploidization. PMID:16260753

Nomura, Taiji; Ishihara, Atsushi; Yanagita, Ryo C.; Endo, Takashi R.; Iwamura, Hajime

2005-01-01

40

Endothelial progenitor cells in atherosclerosis  

PubMed Central

Endothelial progenitor cells (EPCs) are involved in the maintenance of endothelial homoeostasis and in the process of new vessel formation. Experimental and clinical studies have shown that atherosclerosis is associated with reduced numbers and dysfunction of EPCs; and that medications alone are able to partially reverse the impairment of EPCs in patients with atherosclerosis. Therefore, novel EPC-based therapies may provide enhancement in restoring EPCs’ population and improvement of vascular function. Here, for a better understanding of the molecular mechanisms underlying EPC impairment in atherosclerosis, we provide a comprehensive overview on EPC characteristics, phenotypes, and the signaling pathways underlying EPC impairment in atherosclerosis. PMID:22652782

Du, Fuyong; Zhou, Jun; Gong, Ren; Huang, Xiao; Pansuria, Meghana; Virtue, Anthony; Li, Xinyuan; Wang, Hong; Yang, Xiao-Feng

2012-01-01

41

Evolution of physiological responses to salt stress in hexaploid wheat  

PubMed Central

Hexaploid bread wheat (Triticum aestivum L., genome BBAADD) is generally more salt tolerant than its tetraploid wheat progenitor (Triticum turgidum L.). However, little is known about the physiological basis of this trait or about the relative contributions of allohexaploidization and subsequent evolutionary genetic changes on the trait development. Here, we compared the salt tolerance of a synthetic allohexaploid wheat (neo-6x) with its tetraploid (T. turgidum; BBAA) and diploid (Aegilops tauschii; DD) parents, as well as a natural hexaploid bread wheat (nat-6x). We studied 92 morphophysiological traits and analyzed homeologous gene expression of a major salt-tolerance gene High-Affinity K+ Transporter 1;5 (HKT1;5). We observed that under salt stress, neo-6x exhibited higher fitness than both of its parental genotypes due to inheritance of favorable traits like higher germination rate from the 4x parent and the stronger root Na+ retention capacity from the 2x parent. Moreover, expression of the D-subgenome HKT1;5 homeolog, which is responsible for Na+ removal from the xylem vessels, showed an immediate transcriptional reprogramming following allohexaploidization, i.e., from constitutive high basal expression in Ae. tauschii (2x) to salt-induced expression in neo-6x. This phenomenon was also witnessed in the nat-6x. An integrated analysis of 92 traits showed that, under salt-stress conditions, neo-6x resembled more closely the 2x than the 4x parent, suggesting that the salt stress induces enhanced expressivity of the D-subgenome homeologs in the synthetic hexaploid wheat. Collectively, the results suggest that condition-dependent functionalization of the subgenomes might have contributed to the wide-ranging adaptability of natural hexaploid wheat. PMID:25074914

Yang, Chunwu; Zhao, Long; Zhang, Huakun; Yang, Zongze; Wang, Huan; Wen, Shanshan; Zhang, Chunyu; Rustgi, Sachin; von Wettstein, Diter; Liu, Bao

2014-01-01

42

Progenitor cell therapy for heart disease  

Microsoft Academic Search

Many cell types are currently being studied as potential sources of cardiomyocytes for cell transplantation therapy to repair and regenerate damaged myocardium. The question remains as to which progenitor cell represents the best candidate. Bone marrow-derived cells and endothelial progenitor cells have been tested in clinical studies. These cells are safe, but their cardiogenic potential is controversial. The functional benefits

Christine Gonzales; Thierry Pedrazzini

2009-01-01

43

Neural progenitors from human embryonic stem cells  

Microsoft Academic Search

The derivation of neural progenitor cells from human embryonic stem (ES) cells is of value both in the study of early human neurogenesis and in the creation of an unlimited source of donor cells for neural transplantation therapy. Here we report the generation of enriched and expandable preparations of proliferating neural prog- enitors from human ES cells. The neural progenitors

Benjamin E. Reubinoff; Pavel Itsykson; Tikva Turetsky; Martin F. Pera; Etti Reinhartz; Anna Itzik; Tamir Ben-Hur

2000-01-01

44

Wheat quality evaluation methods to predict wheat flour tortilla production  

E-print Network

WHEAT QUALITY EVALUATION METHODS TO PREDICT WHEAT FLOUR TORTILLA PRODUCTION A Thesis by BARBIE DENISE SULLINS Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE August 1997 Major Subject: Food Science and Technology WHEAT QUALITY EVALUATION METHODS TO PREDICT WHEAT FLOUR TORTILLA PRODUCTION A Thesis by BARBIE DENISE SULLINS Submitted to Texas A8M University in partial fulfillment...

Sullins, Barbie Denise

2012-06-07

45

Genetic diversity of wheat storage proteins and bread wheat quality  

Microsoft Academic Search

To understand the genetic and biochemical basis of the bread makingquality of wheat varieties, a large experiment was carried out with a set of162 hexaploid bread wheat varieties registered in the French or EuropeanWheat Catalogue. This material was used to analyse their allelic compositionat the twelve main storage protein loci. A large genetic and biochemicaldiversity of the gluten proteins was

G. Branlard; M. Dardevet; R. Saccomano; F. Lagoutte; J. Gourdon

2001-01-01

46

Progenitors of type Ia supernovae  

NASA Astrophysics Data System (ADS)

Type Ia supernovae are important, but mysterious cosmological tools. Their standard brightnesses have enabled cosmologists to measure extreme distances and to discover dark energy. However, the nature of their progenitor mechanisms remains elusive, with many competing models offering only partial clues to their origins. Here, type Ia supernova delay times are explored using analytical models. Combined with a new observation technique, this model places new constraints on the characteristic time delay between the formation of stars and the first type Ia supernovae. This derived delay time (500 million years) implies low-mass companions for single degenerate progenitor scenarios. In the latter portions of this dissertation, two progenitor mechanisms are simulated in detail; white dwarf collisions and mergers. From the first of these simulations, it is evident that white dwarf collisions offer a viable and unique pathway to producing type Ia supernovae. Many of the combinations of masses simulated produce sufficient quantities of 56 Ni (up to 0.51 solar masses) to masquerade as normal type Ia supernovae. Other combinations of masses produce 56 Ni yields that span the entire range of supernova brightnesses, from the very dim and underluminous, with 0.14 solar masses, to the over-bright and superluminous, with up to 1.71 solar masses. The 56 Ni yield in the collision simulations depends non-linearly on total system mass, mass ratio, and impact parameter. Using the same numerical tools as in the collisions examination, white dwarf mergers are studied in detail. Nearly all of the simulations produce merger remnants consisting of a cold, degenerate core surrounded by a hot accretion disk. The properties of these disks have strong implications for various viscosity treatments that have attempted to pin down the accretion times. Some mass combinations produce super-Chandrasekhar cores on shorter time scales than viscosity driven accretion. A handful of simulations also exhibit helium detonations on the surface of the primary that bear a resemblance to helium novae. Finally, some of the preliminary groundwork that has been laid for constructing a new numerical tool is discussed. This new tool advances the merger simulations further than any research group has done before, and has the potential to answer some of the lingering questions that the merger study has uncovered. The results of thermal diffusion tests using this tool have a remarkable correspondence to analytical predictions.

Raskin, Cody

47

Biofortification of wheat grain with iron and zinc: integrating novel genomic resources and knowledge from model crops  

PubMed Central

Wheat, like many other staple cereals, contains low levels of the essential micronutrients iron and zinc. Up to two billion people worldwide suffer from iron and zinc deficiencies, particularly in regions with predominantly cereal-based diets. Although wheat flour is commonly fortified during processing, an attractive and more sustainable solution is biofortification, which requires developing new varieties of wheat with inherently higher iron and zinc content in their grains. Until now most studies aimed at increasing iron and zinc content in wheat grains have focused on discovering natural variation in progenitor or related species. However, recent developments in genomics and transformation have led to a step change in targeted research on wheat at a molecular level. We discuss promising approaches to improve iron and zinc content in wheat using knowledge gained in model grasses. We explore how the latest resources developed in wheat, including sequenced genomes and mutant populations, can be exploited for biofortification. We also highlight the key research and practical challenges that remain in improving iron and zinc content in wheat. PMID:24600464

Borrill, Philippa; Connorton, James M.; Balk, Janneke; Miller, Anthony J.; Sanders, Dale; Uauy, Cristobal

2014-01-01

48

Recent Advances in Wheat Allelopathy  

Microsoft Academic Search

Wheat (Triticum aestivum), as one of the world’s important crops, has been studied in depth for its allelopathic potential in weed management. Research\\u000a on wheat allelopathy has progressed rapidly from the initial evaluation of allelopathic potential to the identification of\\u000a allelochemicals and genetic markers associated with wheat allelopathy. Allelopathic activity varied among wheat accessions.\\u000a Significant varietal differences in the production

Hanwen Wu; Min An; De Li Liu; Jim Pratley; Deirdre Lemerle

49

Discovery and mapping of single feature polymorphisms in wheat using Affymetrix arrays  

PubMed Central

Background Wheat (Triticum aestivum L.) is a staple food crop worldwide. The wheat genome has not yet been sequenced due to its huge genome size (~17,000 Mb) and high levels of repetitive sequences; the whole genome sequence may not be expected in the near future. Available linkage maps have low marker density due to limitation in available markers; therefore new technologies that detect genome-wide polymorphisms are still needed to discover a large number of new markers for construction of high-resolution maps. A high-resolution map is a critical tool for gene isolation, molecular breeding and genomic research. Single feature polymorphism (SFP) is a new microarray-based type of marker that is detected by hybridization of DNA or cRNA to oligonucleotide probes. This study was conducted to explore the feasibility of using the Affymetrix GeneChip to discover and map SFPs in the large hexaploid wheat genome. Results Six wheat varieties of diverse origins (Ning 7840, Clark, Jagger, Encruzilhada, Chinese Spring, and Opata 85) were analyzed for significant probe by variety interactions and 396 probe sets with SFPs were identified. A subset of 164 unigenes was sequenced and 54% showed polymorphism within probes. Microarray analysis of 71 recombinant inbred lines from the cross Ning 7840/Clark identified 955 SFPs and 877 of them were mapped together with 269 simple sequence repeat markers. The SFPs were randomly distributed within a chromosome but were unevenly distributed among different genomes. The B genome had the most SFPs, and the D genome had the least. Map positions of a selected set of SFPs were validated by mapping single nucleotide polymorphism using SNaPshot and comparing with expressed sequence tags mapping data. Conclusion The Affymetrix array is a cost-effective platform for SFP discovery and SFP mapping in wheat. The new high-density map constructed in this study will be a useful tool for genetic and genomic research in wheat. PMID:19480702

Bernardo, Amy N; Bradbury, Peter J; Ma, Hongxiang; Hu, Shengwa; Bowden, Robert L; Buckler, Edward S; Bai, Guihua

2009-01-01

50

Characterization of HMW-GS and evaluation of their diversity in morphologically elite synthetic hexaploid wheats.  

PubMed

High molecular weight glutenin subunit composition and variation in 95 Elite-1 synthetic hexaploid (SH) wheats (Triticum turgidum/Aegilops tauschii; 2n = 6× = 42; AABBDD) were determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis method (SDS-PAGE). Twenty two different alleles at Glu-1 loci in SHs were observed. Forty four different patterns of HMW-GS in synthetics were found. This higher HMW glutenin composition was due to higher proportion of D-genome encoded subunits in these SHs. 8% urea/SDS-PAGE better discriminated subunit 2* than 12% gels. However 12% urea/SDS-PAGE allowed differentiated mobility of Glu-D(t)1 subunits. Genetic variability at Glu-D(t)1 locus was greater than Glu-A1 and Glu-B1 loci. The relative high frequency of superior alleles, Glu-B1b and Glu-D(t)1d indicated the superior bread making quality attributes embedded in these synthetic hexaploid wheats. Of the 95 Elite-1 SHs 27.1% possessed superior alleles at Glu-A1 and 51% had superior alleles at Glu-B1 locus. At Glu-D(t)1 frequency of inferior allele 1Dx2 + 1Dy12 was very low (5.26%) and nine different rare alleles along with the higher frequency (22.1%) of D-genome encoded subunit, 1Dx5 + 1Dy10, were observed. These superior alleles shall form the priority selective sieve for their usage in wheat improvement efforts. PMID:23341752

Rasheed, Awais; Safdar, Tania; Gul-Kazi, Alvina; Mahmood, Tariq; Akram, Zahid; Mujeeb-Kazi, Abdul

2012-12-01

51

Basics of Stem and Progenitor Cells  

Microsoft Academic Search

\\u000a This chapter will define key terms and introduce important basic information about the fundamental building blocks of the\\u000a entire text: the stem and progenitor cells. After a brief discussion of terminology central to the field, we will explore\\u000a the various stem and progenitor cells including bone marrow-derived cell populations, specific niche-derived cell populations,\\u000a as well as special situations such as

Matthew T. Harting

52

Progenitor cells in pulmonary vascular remodeling.  

PubMed

Pulmonary hypertension is characterized by cellular and structural changes in the walls of pulmonary arteries. Intimal thickening and fibrosis, medial hypertrophy and fibroproliferative changes in the adventitia are commonly observed, as is the extension of smooth muscle into the previously non-muscularized vessels. A majority of these changes are associated with the enhanced presence of ?-SM-actin+ cells and inflammatory cells. Atypical abundances of functionally distinct endothelial cells, particularly in the intima (plexiform lesions), and also in the perivascular regions, are also described. At present, neither the origin(s) of these cells nor the molecular mechanisms responsible for their accumulation, in any of the three compartments of the vessel wall, have been fully elucidated. The possibility that they arise from either resident vascular progenitors or bone marrow-derived progenitor cells is now well established. Resident vascular progenitor cells have been demonstrated to exist within the vessel wall, and in response to certain stimuli, to expand and express myofibroblastic, endothelial or even hematopoietic markers. Bone marrow-derived or circulating progenitor cells have also been shown to be recruited to sites of vascular injury and to assume both endothelial and SM-like phenotypes. Here, we review the data supporting the contributory role of vascular progenitors (including endothelial progenitor cells, smooth muscle progenitor cells, pericytes, and fibrocytes) in vascular remodeling. A more complete understanding of the processes by which progenitor cells modulate pulmonary vascular remodeling will undoubtedly herald a renaissance of therapies extending beyond the control of vascular tonicity and reduction of pulmonary artery pressure. PMID:22034593

Yeager, Michael E; Frid, Maria G; Stenmark, Kurt R

2011-01-01

53

Wheat Germ DNA Extraction  

NSDL National Science Digital Library

This laboratory exercise is designed to show learners how DNA can easily be extracted from wheat germ using simple materials. Use this experiment to supplement any unit on genetics and to demonstrate how scientists study DNA. Adult supervision is recommended. This resource guide includes tips and suggestions for instructors as well as other DNA extraction experiments and a chart for learners to answer questions.

Hays, Lana

2009-01-01

54

Floral Initiation in Wheat  

Microsoft Academic Search

The gap in understanding between genetic control and physiological processes of differentiation is far from being bridged; but it is being narrowed by a coordinated approach from both directions. The genetic system controlling the stability of floral differentiation in a series of wheat genotypes with progressively disturbed floral morphogenesis provides an experimental means of investigating the elements of the physiological

Otto Frankel

1976-01-01

55

Wheat Breeding Activity  

NSDL National Science Digital Library

This interactive activity goes through the basic process used in a wheat breeding program. Crossing, genetic variation, selection and elements of DNA technology are discussed within this activity. The material is aimed towards high school or introductory life science undergraduate students.

56

Haplotype Variation of Glu-D1 Locus and the Origin of Glu-D1d Allele Conferring Superior End-Use Qualities in Common Wheat  

PubMed Central

In higher plants, seed storage proteins (SSPs) are frequently expressed from complex gene families, and allelic variation of SSP genes often affects the quality traits of crops. In common wheat, the Glu-D1 locus, encoding 1Dx and 1Dy SSPs, has multiple alleles. The Glu-D1d allele frequently confers superior end-use qualities to commercial wheat varieties. Here, we studied the haplotype structure of Glu-D1 genomic region and the origin of Glu-D1d. Using seven diagnostic DNA markers, 12 Glu-D1 haplotypes were detected among common wheat, European spelt wheat (T. spelta, a primitive hexaploid relative of common wheat), and Aegilops tauschii (the D genome donor of hexaploid wheat). By comparatively analyzing Glu-D1 haplotypes and their associated 1Dx and 1Dy genes, we deduce that the haplotype carrying Glu-D1d was likely differentiated in the ancestral hexaploid wheat around 10,000 years ago, and was subsequently transmitted to domesticated common wheat and T. spelta. A group of relatively ancient Glu-D1 haplotypes was discovered in Ae. tauschii, which may serve for the evolution of other haplotypes. Moreover, a number of new Glu-D1d variants were found in T. spelta. The main steps in Glu-D1d differentiation are proposed. The implications of our work for enhancing the utility of Glu-D1d in wheat quality improvement and studying the SSP alleles in other crop species are discussed. PMID:24098671

Li, Yiwen; Zhang, Kunpu; Lou, Haijuan; An, Xueli; Dong, Lingli; Gu, Yong Qiang; Anderson, Olin D.; Liu, Xin; Qin, Huanju; Wang, Daowen

2013-01-01

57

Endothelial progenitor cells: Quo Vadis?  

PubMed Central

The term endothelial progenitor cell (EPC) was coined to refer to circulating cells that displayed the ability to display cell surface antigens similar to endothelial cells in vitro, to circulate and lodge in areas of ischemia or vascular injury, and to facilitate the repair of damaged blood vessels or augment development of new vessels as needed by a tissue. More than 10 years after the first report, the term EPC is used to refer to a host of circulating cells that display some or all of the qualities indicated above, however, essentially all of the cells are now known to be members of the hematopoietic lineage. The exception is a rare viable circulating endothelial cell with clonal proliferative potential that displays the ability to spontaneously form inosculating human blood vessels upon implantation into immunodeficient murine host tissues. This paper will review the current lineage relationships among all the cells called EPC and will propose that the term EPC be retired and that each of the circulating cell subsets be referred to according to the terms already existent for each subset. This article is part of a special issue entitled, "Cardiovascular Stem Cells Revisited". PMID:20673769

Richardson, Matthew R.; Yoder, Mervin C.

2012-01-01

58

Characterization and expression analysis of WOX5 genes from wheat and its relatives.  

PubMed

The WUSCHEL (WUS)-related homeobox (WOX) gene family plays an important role in coordinating gene transcription in the early phases of embryogenesis. In this study, we isolated and characterized WOX5 from common wheat and its relatives Triticum monococcum, Triticum urartu, Aegilops speltoides, Aegilops searsii, Aegilops sharonensis, Aegilops longissima, Aegilops bicornis, Aegilops tauschii, and Triticum turgidum. The size of the characterized WOX5 alleles ranged from 1029 to 1038 bp and encompassed the complete open reading frame (ORF) as well as 5' upstream and 3' downstream sequences. Domain prediction analysis showed that the putative primary structures of wheat WOX5 protein include the highly conserved homeodomain besides the WUS-box domain and the EAR-like domain, which is/are present in some members of the WOX protein family. The full-length ORF was subcloned into a prokaryotic expression vector pET30a, and an approximate 26-kDa protein was successfully expressed in Escherichia coli BL21 (DE3) cells with IPTG induction. The WOX5 genes from wheat-related species exhibit a similar structure to and high sequence similarity with WOX5 genes from common wheat. The degree of divergence and phylogenetic tree analysis among WOX5 alleles suggested the existence of three homoeologous copies in the A, B, or D genome of common wheat. Quantitative PCR results showed that TaWOX5 was primarily expressed in the root and calli induced by auxin and cytokinin, indicating that TaWOX5 may play a role related to root formation or development and is associated with hormone regulation in somatic embryogenesis. PMID:24368329

Zhao, Shan; Jiang, Qian-Tao; Ma, Jian; Zhang, Xiao-Wei; Zhao, Quan-Zhi; Wang, Xiu-Ying; Wang, Chang-Shui; Cao, Xue; Lu, Zhen-Xiang; Zheng, You-Liang; Wei, Yu-Ming

2014-03-01

59

Molecular characterization of vernalization loci VRN1 in wild and cultivated wheats  

PubMed Central

Background Variability of the VRN1 promoter region of the unique collection of spring polyploid and wild diploid wheat species together with diploid goatgrasses (donor of B and D genomes of polyploid wheats) were investigated. Accessions of wild diploid (T. boeoticum, T. urartu) and tetraploid (T. araraticum, T. timopheevii) species were studied for the first time. Results Sequence analysis indicated great variability in the region from -62 to -221 nucleotide positions of the VRN1 promoter region. Different indels were found within this region in spring wheats. It was shown that VRN1 promoter region of B and G genome can also contain damages such as the insertion of the transposable element. Some transcription factor recognition sites including hybrid C/G-box for TaFDL2 protein known as the VRN1 gene upregulator were predicted inside the variable region. It was shown that deletions leading to promoter damage occurred in diploid and polyploid species independently. DNA transposon insertions first occurred in polyploid species. At the same time, the duplication of the promoter region was observed in A genomes of polyploid species. Conclusions We can conclude that supposed molecular mechanism of the VRN1 gene activating in cultivated diploid wheat species T. monococcum is common also for wild T. boeoticum and was inherited by T. monococcum. The spring polyploids are not related in their origin to spring diploids. The spring T. urartu and goatgrass accessions have another mechanism of flowering activation that is not connected with indels in VRN1 promoter region. All obtained data may be useful for detailed insight into origin of spring wheat forms in evolution and domestication process. PMID:20699006

2010-01-01

60

21 CFR 184.1322 - Wheat gluten.  

...of gliadin and glutenin. Wheat gluten is obtained by hydrating wheat flour and mechanically working the sticky mass to separate the wheat gluten from the starch and other flour components. Vital gluten is dried gluten that has retained its...

2014-04-01

61

21 CFR 184.1322 - Wheat gluten.  

Code of Federal Regulations, 2011 CFR

...of gliadin and glutenin. Wheat gluten is obtained by hydrating wheat flour and mechanically working the sticky mass to separate the wheat gluten from the starch and other flour components. Vital gluten is dried gluten that has retained its...

2011-04-01

62

21 CFR 184.1322 - Wheat gluten.  

Code of Federal Regulations, 2010 CFR

...of gliadin and glutenin. Wheat gluten is obtained by hydrating wheat flour and mechanically working the sticky mass to separate the wheat gluten from the starch and other flour components. Vital gluten is dried gluten that has retained its...

2010-04-01

63

21 CFR 184.1322 - Wheat gluten.  

Code of Federal Regulations, 2012 CFR

...of gliadin and glutenin. Wheat gluten is obtained by hydrating wheat flour and mechanically working the sticky mass to separate the wheat gluten from the starch and other flour components. Vital gluten is dried gluten that has retained its...

2012-04-01

64

On the Progenitors of Collapsars  

NASA Astrophysics Data System (ADS)

We investigate possible progenitor stars of Type I collapsars that are assumed to be responsible for the long class of GRBs. Our basic assumption is that in close binary systems a bare massive helium core is formed. This may occur either: (1) by losing the envelope by Roche-Lobe overflow to the companion, or (2) by a merger. For the first case, we will assume 10% of Keplerian rotation of the helium core, as predicted by simulations of rotating massive single stars. In the second case, even faster rotation may occur and we adopt 30%. We then follow the evolution of these cores, initially 15 solar masses of 10% solar metal content, from onset of central helium burning until onset of core collapse. In order to obtain the angular momentum distribution in the pre-collapsed stellar models we investigate different physical models for angular momentum transport and compare the results with what would be required to from a centrifugally supported disk around a central compact object. We also study angular momentum reduction by mass loss. We find that, if only rotationally induced instabilities (Heger et al. 2000) are considered, or magnetic fields (Spruit 2001) and no mass loss, sufficient angular momentum may remain in the core to power a collapsar. However, when this description of magnetic torques is combined with mass loss, the resulting angular momentum is too low. Magnetic field torques as described by Spruit & Phinney (1998) result in too low spin rates in any case studied. This work has been supported by the NSF (AST-9731569) and the DOE (B347885).

Woosley, S. E.; Heger, A.

2001-05-01

65

Structures of the three homoeologous loci of wheat benzoxazinone biosynthetic genes TaBx3 and TaBx4 and characterization of their promoter sequences  

Microsoft Academic Search

Common wheat (2n = 6x = 42, genome formula AABBDD) accumulates benzoxazinones (Bxs) as defensive compounds. There are five Bx biosynthetic genes\\u000a (TaBx1–TaBx5), and their homoeologous alleles are located on all three homoeologous chromosomes of the A, B and D genomes. Here the molecular\\u000a structures of the TaBx3 and TaBx4 loci, both of which are located on chromosomes 5A, 5B and 5D, were revealed

Taiji Nomura; Shuhei Nasuda; Kanako Kawaura; Yasunari Ogihara; Nobuhiko Kato; Fumihiko Sato; Toshio Kojima; Atsushi Toyoda; Hajime Iwamura; Takashi R. Endo

2008-01-01

66

Wheat Invertases 1  

PubMed Central

Wheat coleoptiles have two distinct invertases, a soluble and a cell wall-bound form as indicated by results from cytochemical and biochemical studies. These enzyme activities differ in their pH optima, chromatographic behavior on diethylaminoethyl cellulose, kinetic properties, thermal stability, and response to light treatment. The soluble invertase was purified to near homogeneity by diethylaminoethyl-cellulose, concanavalin-A Sepharose, and Sephacryl S-300 chromatography. The overall purification was 175-fold with a recovery of about 26%. The holoenzyme has an apparent molecular weight of 158,000 and subunit molecular weight of 53,000 as estimated by polyacrylamide gel electrophoresis under denaturing conditions. Illumination of wheat seedlings caused an increase in the cell wall, but not the soluble, invertase activity. Images Fig. 1 Fig. 4 PMID:16664223

Krishnan, Hari B.; Blanchette, Joan T.; Okita, Thomas W.

1985-01-01

67

On Phaeosphaeria nodorum in wheat.  

E-print Network

??The fungus Phaeosphaeria nodorum (anamorph Stagonospora nodorum) causes stagonospora nodorum blotch on wheat. Besides environmental conditions the biology of the pathogen is an important parameter… (more)

Blixt, Eva

2009-01-01

68

Endothelial progenitor cells in cardiovascular diseases  

PubMed Central

Endothelial dysfunction has been associated with the development of atherosclerosis and cardiovascular diseases. Adult endothelial progenitor cells (EPCs) are derived from hematopoietic stem cells and are capable of forming new blood vessels through a process of vasculogenesis. There are studies which report correlations between circulating EPCs and cardiovascular risk factors. There are also studies on how pharmacotherapies may influence levels of circulating EPCs. In this review, we discuss the potential role of endothelial progenitor cells as both diagnostic and prognostic biomarkers. In addition, we look at the interaction between cardiovascular pharmacotherapies and endothelial progenitor cells. We also discuss how EPCs can be used directly and indirectly as a therapeutic agent. Finally, we evaluate the challenges facing EPC research and how these may be overcome. PMID:25126384

Lee, Poay Sian Sabrina; Poh, Kian Keong

2014-01-01

69

Transient nuclear Prospero induces neural progenitor quiescence.  

PubMed

Stem cells can self-renew, differentiate, or enter quiescence. Understanding how stem cells switch between these states is highly relevant for stem cell-based therapeutics. Drosophila neural progenitors (neuroblasts) have been an excellent model for studying self-renewal and differentiation, but quiescence remains poorly understood. In this study, we show that when neuroblasts enter quiescence, the differentiation factor Prospero is transiently detected in the neuroblast nucleus, followed by the establishment of a unique molecular profile lacking most progenitor and differentiation markers. The pulse of low level nuclear Prospero precedes entry into neuroblast quiescence even when the timing of quiescence is advanced or delayed by changing temporal identity factors. Furthermore, loss of Prospero prevents entry into quiescence, whereas a pulse of low level nuclear Prospero can drive proliferating larval neuroblasts into quiescence. We propose that Prospero levels distinguish three progenitor fates: absent for self-renewal, low for quiescence, and high for differentiation. PMID:25354199

Lai, Sen-Lin; Doe, Chris Q

2014-01-01

70

Circulating and tissue resident endothelial progenitor cells  

PubMed Central

Progenitor cells for the endothelial lineage have been widely investigated for more than a decade, but continue to be controversial since no unique identifying marker has yet been identified. This review will begin with a discussion of the basic tenets originally proposed for proof that a cell displays properties of an endothelial progenitor cell. We then provide an overview of the methods for putative endothelial progenitor cell derivation, expansion, and enumeration. This discussion includes consideration of cells that are present in the circulation as well as cells resident in the vascular endothelial intima. Finally, we provide some suggested changes in nomenclature that would greatly clarify and demystify the cellular elements involved in vascular repair. PMID:23794280

Basile, David P.; Yoder, Mervin C.

2014-01-01

71

THE AGES OF TYPE Ia SUPERNOVA PROGENITORS  

SciTech Connect

Using light curves and host galaxy spectra of 101 Type Ia supernovae (SNe Ia) with redshift z {approx}< 0.3 from the Sloan Digital Sky Survey Supernova Survey (SDSS-SN), we derive the SN Ia rate as a function of progenitor age (the delay time distribution, DTD). We use the VESPA stellar population synthesis algorithm to analyze the SDSS spectra of all galaxies in the field searched by SDSS-SN, giving us a reference sample of 77,000 galaxies for our SN Ia hosts. Our method does not assume any a priori shape for the DTD and is therefore minimally parametric. We present the DTD in physical units for high-stretch (luminous, slow declining) and low-stretch (subluminous, fast declining) supernovae in three progenitor age bins. We find strong evidence of two progenitor channels: one that produces high-stretch SNe Ia {approx}<400 Myr after the birth of the progenitor system, and one that produces low-stretch SNe Ia with a delay {approx}>2.4 Gyr. We find that each channel contributes roughly half of the Type Ia rate in our reference sample. We also construct the average spectra of high-stretch and low-stretch SN Ia host galaxies, and find that the difference of these spectra looks like a main-sequence B star with nebular emission lines indicative of star formation. This supports our finding that there are two populations of SNe Ia, and indicates that the progenitors of high-stretch supernovae are at the least associated with very recent star formation in the last few tens of Myr. Our results provide valuable constraints for models of Type Ia progenitors and may help improve the calibration of SNe Ia as standard candles.

Brandt, Timothy D.; Aubourg, Eric; Strauss, Michael A. [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States); Tojeiro, Rita [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth, PO1 3FX (United Kingdom); Heavens, Alan [SUPA, Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9-3HJ (United Kingdom); Jimenez, Raul [ICREA and Institute for Sciences of the Cosmos (ICCUB), University of Barcelona, Barcelona 08028 (Spain)

2010-09-15

72

Could Cancer Initiate From Bone Marrow Progenitors?  

PubMed Central

Background Defining cancer stem cells and their origins is of much controversy,and constitutes a challenged knockout for cell targeting- anticancer drugs. Herein,we put forward a hypothetic model for cancer stem cells initiation from bone marrow stem cells. These later, will differentiate into an ancestral progenitor that activates a memorial program - the black box cassette- that is responsible of abnormal neo-organogenesis in the form of tumors and metastases. To approve this model, we assume that characterizing and investigating the most primitive forms of the bone marrow progenitors is required; both inside their niche and in circulation of cancer patients. PMID:25250119

Ben Nasr, Hmed; Hammami, Serria Turky; Zeghal, Khaled

2013-01-01

73

HETEROSIS STUDIES IN WHEAT CROSSES  

Microsoft Academic Search

A study was undertaken to estimate the heterotic and heterobeltiotic effects in wheat during the year 2002-03 at Wheat Research Institute, AARI, Faisalabad, Pakistan to identify combinations expressing high hybrid vigour. Fifteen F1 single crosses were developed and planted alongwith their 8 parents. Data were recorded on grain yield, tillers per plant, grains per spike, 1000-grain weight and plant height.

Fida Hussain; Makhdoom Hussain; M. Muzaffar Iqbal; Mansoor A. Akhtar

2007-01-01

74

Mathematical modeling supports substantial mouse neural progenitor cell death  

Microsoft Academic Search

BACKGROUND: Existing quantitative models of mouse cerebral cortical development are not fully constrained by experimental data. RESULTS: Here, we use simple difference equations to model neural progenitor cell fate decisions, incorporating intermediate progenitor cells and initially low rates of neural progenitor cell death. Also, we conduct a sensitivity analysis to investigate possible uncertainty in the fraction of cells that divide,

Michael J McConnell; Hugh R MacMillan; Jerold Chun

2009-01-01

75

p63 and Brg1 control developmentally regulated higher-order chromatin remodelling at the epidermal differentiation complex locus in epidermal progenitor cells.  

PubMed

Chromatin structural states and their remodelling, including higher-order chromatin folding and three-dimensional (3D) genome organisation, play an important role in the control of gene expression. The role of 3D genome organisation in the control and execution of lineage-specific transcription programmes during the development and differentiation of multipotent stem cells into specialised cell types remains poorly understood. Here, we show that substantial remodelling of the higher-order chromatin structure of the epidermal differentiation complex (EDC), a keratinocyte lineage-specific gene locus on mouse chromosome 3, occurs during epidermal morphogenesis. During epidermal development, the locus relocates away from the nuclear periphery towards the nuclear interior into a compartment enriched in SC35-positive nuclear speckles. Relocation of the EDC locus occurs prior to the full activation of EDC genes involved in controlling terminal keratinocyte differentiation and is a lineage-specific, developmentally regulated event controlled by transcription factor p63, a master regulator of epidermal development. We also show that, in epidermal progenitor cells, p63 directly regulates the expression of the ATP-dependent chromatin remodeller Brg1, which binds to distinct domains within the EDC and is required for relocation of the EDC towards the nuclear interior. Furthermore, Brg1 also regulates gene expression within the EDC locus during epidermal morphogenesis. Thus, p63 and its direct target Brg1 play an essential role in remodelling the higher-order chromatin structure of the EDC and in the specific positioning of this locus within the landscape of the 3D nuclear space, as required for the efficient expression of EDC genes in epidermal progenitor cells during skin development. PMID:24346698

Mardaryev, Andrei N; Gdula, Michal R; Yarker, Joanne L; Emelianov, Vladimir U; Emelianov, Vladimir N; Poterlowicz, Krzysztof; Sharov, Andrey A; Sharova, Tatyana Y; Scarpa, Julie A; Joffe, Boris; Solovei, Irina; Chambon, Pierre; Botchkarev, Vladimir A; Fessing, Michael Y

2014-01-01

76

The progenitors of subluminous type Ia supernovae  

SciTech Connect

We find that spectroscopically peculiar subluminous SNe Ia come from an old population. Of the thirteen subluminous SNe Ia known, nine are found in E/S0 galaxies, and the remainder are found in early-type spirals. The probability that this is a chance occurrence is only 0.1%. The finding that subluminous SNe Ia are associated with an older stellar population indicates that for a sufficiently large lookback time (already accessible in current high redshift searches) they will not be found. Due to a scarcity in old populations, hydrogen and helium main sequence stars and He red giant stars that undergo Roche lobe overflow are unlikely to be the progenitors of subluminous SNe Ia. Earlier findings that overluminous SNe Ia (DELTA m{sub 15} (B) < 0.94) come from a young progenitor population are confirmed. The fact that subluminous SNe Ia and overluminous SNe Ia come from different progenitor populations and also have different properties is a prediction of the CO white dwarf merger progenitor scenario.

Howell, D. Andrew

2001-02-01

77

In vivo identification of periodontal progenitor cells.  

PubMed

The periodontal ligament contains progenitor cells; however, their identity and differentiation potential in vivo remain poorly characterized. Previous results have suggested that periodontal tissue progenitors reside in perivascular areas. Therefore, we utilized a lineage-tracing approach to identify and track periodontal progenitor cells from the perivascular region in vivo. We used an alpha-smooth muscle actin (?SMA) promoter-driven and tamoxifen-inducible Cre system (?SMACreERT2) that, in combination with a reporter mouse line (Ai9), permanently labels a cell population, termed 'SMA9'. To trace the differentiation of SMA9-labeled cells into osteoblasts/cementoblasts, we utilized a Col2.3GFP transgene, while expression of Scleraxis-GFP was used to follow differentiation into periodontal ligament fibroblasts during normal tissue formation and remodeling following injury. In uninjured three-week-old SMA9 mice, tamoxifen labeled a small population of cells in the periodontal ligament that expanded over time, particularly in the apical region of the root. By 17 days and 7 weeks after labeling, some SMA9-labeled cells expressed markers indicating differentiation into mature lineages, including cementocytes. Following injury, SMA9 cells expanded, and differentiated into cementoblasts, osteoblasts, and periodontal ligament fibroblasts. SMA9-labeled cells represent a source of progenitors that can give rise to mature osteoblasts, cementoblasts, and fibroblasts within the periodontium. PMID:23735585

Roguljic, H; Matthews, B G; Yang, W; Cvija, H; Mina, M; Kalajzic, I

2013-08-01

78

Adrenal myelolipoma: a mingle of progenitor cells?  

PubMed

Adrenal myelolipoma (AML) is a rare benign tumour composed or mature haematopoietic tissue and fat. The tumour is functionally inert and is usually detected incidentally. Mainly introduced in case reports, the tumourigenesis of AML is poorly understood with 3 historical hypotheses seemingly unrelated to each other. Here we propose the tumourigenic pathway based on the novel findings on stem/progenitor cell and our preliminary data. We hypothesize the tumourigenesis as follows: the fat components are derived by the mesenchymal stem cells of stromal fat of adrenal cortex under certain stimuli. Mature adipocytes begin to accumulate and become inflammatory stimulating neighbouring adrenal cortex tissue to release possibly G-CSF to recruit circulating haematopoietic progenitors. During the tumour growth, haematopoietic cell in the central part acquire energy from burning the surrounding fat until they are fully differentiated and division stops. Lacking the ability to further grow, the central part undergoes necrosis and calcification whilst the peripheral part continues to slowly pile up newly derived adipocytes and haematopoietic progenitor cells. The necrosis or calcification of the tumour the inflammation persists and the tumour generates a self-growing signalling loop, entailing a continuous growth even without further stimuli. Our theory offers a logical explanation to the diverse phenomena identified on AML and unifies the historical theories. Future studies may focus on the stem/progenitor cell profiles of AML to confirm and supplement our hypothesis. PMID:23566655

Feng, Chenchen; Jiang, Haowen; Ding, Qiang; Wen, Hui

2013-06-01

79

Proteoglycan synthesis by hematopoietic progenitor cells  

SciTech Connect

The synthesis of proteoglycans (PG) by hematopoietic stromal cells has been reported. But PG synthesis by hematopoietic progenitor cells has not been explored. We have studied synthesis, cellular distribution, and molecular characteristics of PG by a cloned interleukin-3 (IL-3)-dependent hematopoietic progenitor cell line, FDCP-1, which is cloned from murine long-term marrow cultures. Under appropriate conditions the cell can differentiate into granulocytes and macrophages, and therefore, can be considered CFU-GM equivalent. The pattern of PG synthesis was studied by 35SO4 labeling. FDCP-1 cells actively synthesize PG, which are distributed in the intracellular, membrane-associated (MP), and extracellular pools. After purification of the 35S-labeled material by ion-exchange and gel filtration techniques, a single chondroitin sulfate-PG (CIS-PG) was observed to be present in the three studied pools. By Sepharose CL-4B chromatography, this PG has a Kav of 0.47, which after alkaline treatment is shifted to a Kav of 0.67. This indicates the proteoglycan nature of the 35SO4-labeled material. The MP CIS-PG is not stable. It is released to the culture medium where it is subsequently processed. However, in the presence of hematopoietic stromal cells D2X, the stability of MP proteoglycan of FDCP-1 cells is enhanced, suggesting that the synthesis of PG by progenitor cells and its accumulation in the membrane may have a role in the interaction between progenitor and stromal cells.

Minguell, J.J.; Tavassoli, M. (Veterans Administration Medical Center, Jackson, MS (USA))

1989-05-15

80

Wheat Production in Texas.  

E-print Network

of bakery flour. Comanche (Oro x Tenmarq) was developer1 by the Kansas station but distributed simultane- ously by the Kansas, Oklahoma and Texas sta- tions in 1942. The variety is widely adapted and because of its excellent milling and baking char... 57.0 5-1 6-1 4 56.3 5-3 5-29 Figure 14. Bread dough as mixed in a modern bakery plant. This mass of dough will produce hundreds of loaves of bread. are mild, so intermediate winter-type and true spring-type wheat varieties may be grown from...

Atkins, I. M.; Porter, K. B.; Lahr, Keith; Merkle, Owen G.; Futrell, M. C.

1960-01-01

81

Wheat Pasture Poisoning.  

E-print Network

treatment appears to be the injection of a calcium gluconate solution with or without fortification with magnesium and phosphorus. Recovery seems to be speeded by removing the cow from wheat pasture fox a short time. No recurrence was o~bselrved ii animal... in the plant as a possible cause of grass tetany. The minerals were potassium, sodium, magnesium and calcium. They observed changes in certain of these ratios in for- age when cases of grass tetany developed in the Netherlands. However, when these same...

Crookshank, H. R.; Sims, Frank H.

1956-01-01

82

Supernova Remnant Progenitor Masses in M31  

NASA Astrophysics Data System (ADS)

Using Hubble Space Telescope photometry, we age-date 59 supernova remnants (SNRs) in the spiral galaxy M31 and use these ages to estimate zero-age main-sequence masses (M ZAMS) for their progenitors. To accomplish this, we create color-magnitude diagrams (CMDs) and employ CMD fitting to measure the recent star formation history of the regions surrounding cataloged SNR sites. We identify any young coeval population that likely produced the progenitor star, then assign an age and uncertainty to that population. Application of stellar evolution models allows us to infer the M ZAMS from this age. Because our technique is not contingent on identification or precise location of the progenitor star, it can be applied to the location of any known SNRs. We identify significant young star formation around 53 of the 59 SNRs and assign progenitor masses to these, representing a factor of ~2 increase over currently measured progenitor masses. We consider the remaining six SNRs as either probable Type Ia candidates or the result of core-collapse progenitors that have escaped their birth sites. In general, the distribution of recovered progenitor masses is bottom-heavy, showing a paucity of the most massive stars. If we assume a single power-law distribution, dN/dMvpropM ?, then we find a distribution that is steeper than a Salpeter initial mass function (IMF) (? = -2.35). In particular, we find values of ? outside the range -2.7 >= ? >= -4.4 to be inconsistent with our measured distribution at 95% confidence. If instead we assume a distribution that follows a Salpeter IMF up to some maximum mass, then we find that values of M Max > 26 are inconsistent with the measured distribution at 95% confidence. In either scenario, the data suggest that some fraction of massive stars may not explode. The result is preliminary and requires more SNRs and further analysis. In addition, we use our distribution to estimate a minimum mass for core collapse between 7.0 and 7.8 M ?.

Jennings, Zachary G.; Williams, Benjamin F.; Murphy, Jeremiah W.; Dalcanton, Julianne J.; Gilbert, Karoline M.; Dolphin, Andrew E.; Fouesneau, Morgan; Weisz, Daniel R.

2012-12-01

83

SUPERNOVA REMNANT PROGENITOR MASSES IN M31  

SciTech Connect

Using Hubble Space Telescope photometry, we age-date 59 supernova remnants (SNRs) in the spiral galaxy M31 and use these ages to estimate zero-age main-sequence masses (M{sub ZAMS}) for their progenitors. To accomplish this, we create color-magnitude diagrams (CMDs) and employ CMD fitting to measure the recent star formation history of the regions surrounding cataloged SNR sites. We identify any young coeval population that likely produced the progenitor star, then assign an age and uncertainty to that population. Application of stellar evolution models allows us to infer the M{sub ZAMS} from this age. Because our technique is not contingent on identification or precise location of the progenitor star, it can be applied to the location of any known SNRs. We identify significant young star formation around 53 of the 59 SNRs and assign progenitor masses to these, representing a factor of {approx}2 increase over currently measured progenitor masses. We consider the remaining six SNRs as either probable Type Ia candidates or the result of core-collapse progenitors that have escaped their birth sites. In general, the distribution of recovered progenitor masses is bottom-heavy, showing a paucity of the most massive stars. If we assume a single power-law distribution, dN/dM{proportional_to}M{sup {alpha}}, then we find a distribution that is steeper than a Salpeter initial mass function (IMF) ({alpha} = -2.35). In particular, we find values of {alpha} outside the range -2.7 {>=} {alpha} {>=} -4.4 to be inconsistent with our measured distribution at 95% confidence. If instead we assume a distribution that follows a Salpeter IMF up to some maximum mass, then we find that values of M{sub Max} > 26 are inconsistent with the measured distribution at 95% confidence. In either scenario, the data suggest that some fraction of massive stars may not explode. The result is preliminary and requires more SNRs and further analysis. In addition, we use our distribution to estimate a minimum mass for core collapse between 7.0 and 7.8 M{sub Sun }.

Jennings, Zachary G.; Williams, Benjamin F.; Dalcanton, Julianne J.; Gilbert, Karoline M.; Fouesneau, Morgan; Weisz, Daniel R. [Department of Astronomy, University of Washington Seattle, Box 351580, WA 98195 (United States); Murphy, Jeremiah W. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Dolphin, Andrew E., E-mail: zachjenn@uw.edu, E-mail: adolphin@raytheon.com [Raytheon, 1151 East Hermans Road, Tucson, AZ 85706 (United States)

2012-12-10

84

Novel Neuronal Phenotypes from Neural Progenitor Cells  

PubMed Central

We report the first isolation of progenitor cells from the hypothalamus, a derivative of the embryonic basal plate that does not exhibit neurogenesis postnatally. Neurons derived from hypothalamic progenitor cells were compared with those derived from progenitor cultures of hippocampus, an embryonic alar plate derivative that continues to support neurogenesis in vivo into adulthood. Aside from their different embryonic origins and their different neurogenic potential in vivo, these brain regions were chosen because they are populated with cells of three different categories: Category I cells are generated in both hippocampus and hypothalamus, Category II cells are generated in the hypothalamus but are absent from the hippocampus, and Category III is a cell type generated in the olfactory placode that migrates into the hypothalamus during development. Stem-like cells isolated from other brain regions, with the ability to generate neurons and glia, produce neurons of several phenotypes including gabaergic, dopaminergic, and cholinergic lineages. In the present study, we extended our observations into neuroendocrine phenotypes. The cultured neural precursors from 7-week-old rat hypothalamus readily generated neuropeptide-expressing neurons. Hippocampal and hypothalamic progenitor cultures converged to indistinguishable populations and produced neurons of all three categories, confirming that even short-term culture confers or selects for immature progenitors with enough plasticity to elaborate neuronal phenotypes usually inhibited in vivo by the local microenvironment. The range of phenotypes generated from neuronal precursors in vitro now includes the peptides found in the neuroendocrine system: corticotropin-releasing hormone, growth hormone-releasing hormone, gonadotropin-releasing hormone, oxytocin, somatostatin, thyrotropin-releasing hormone, and vasopressin. PMID:15044527

Markakis, Eleni A.; Palmer, Theo D.; Randolph-Moore, Lynne; Rakic, Pasko; Gage, Fred H.

2011-01-01

85

Drought tolerance in wheat.  

PubMed

Drought is one of the most important phenomena which limit crops' production and yield. Crops demonstrate various morphological, physiological, biochemical, and molecular responses to tackle drought stress. Plants' vegetative and reproductive stages are intensively influenced by drought stress. Drought tolerance is a complicated trait which is controlled by polygenes and their expressions are influenced by various environmental elements. This means that breeding for this trait is so difficult and new molecular methods such as molecular markers, quantitative trait loci (QTL) mapping strategies, and expression patterns of genes should be applied to produce drought tolerant genotypes. In wheat, there are several genes which are responsible for drought stress tolerance and produce different types of enzymes and proteins for instance, late embryogenesis abundant (lea), responsive to abscisic acid (Rab), rubisco, helicase, proline, glutathione-S-transferase (GST), and carbohydrates during drought stress. This review paper has concentrated on the study of water limitation and its effects on morphological, physiological, biochemical, and molecular responses of wheat with the possible losses caused by drought stress. PMID:24319376

Nezhadahmadi, Arash; Prodhan, Zakaria Hossain; Faruq, Golam

2013-01-01

86

Drought Tolerance in Wheat  

PubMed Central

Drought is one of the most important phenomena which limit crops' production and yield. Crops demonstrate various morphological, physiological, biochemical, and molecular responses to tackle drought stress. Plants' vegetative and reproductive stages are intensively influenced by drought stress. Drought tolerance is a complicated trait which is controlled by polygenes and their expressions are influenced by various environmental elements. This means that breeding for this trait is so difficult and new molecular methods such as molecular markers, quantitative trait loci (QTL) mapping strategies, and expression patterns of genes should be applied to produce drought tolerant genotypes. In wheat, there are several genes which are responsible for drought stress tolerance and produce different types of enzymes and proteins for instance, late embryogenesis abundant (lea), responsive to abscisic acid (Rab), rubisco, helicase, proline, glutathione-S-transferase (GST), and carbohydrates during drought stress. This review paper has concentrated on the study of water limitation and its effects on morphological, physiological, biochemical, and molecular responses of wheat with the possible losses caused by drought stress. PMID:24319376

Prodhan, Zakaria Hossain; Faruq, Golam

2013-01-01

87

Enteric neural progenitors are more efficient than brain-derived progenitors at generating neurons in the colon.  

PubMed

Gut motility disorders can result from an absent, damaged, or dysfunctional enteric nervous system (ENS). Cell therapy is an exciting prospect to treat these enteric neuropathies and restore gut motility. Previous studies have examined a variety of sources of stem/progenitor cells, but the ability of different sources of cells to generate enteric neurons has not been directly compared. It is important to identify the source of stem/progenitor cells that is best at colonizing the bowel and generating neurons following transplantation. The aim of this study was to compare the ability of central nervous system (CNS) progenitors and ENS progenitors to colonize the colon and differentiate into neurons. Genetically labeled CNS- and ENS-derived progenitors were cocultured with aneural explants of embryonic mouse colon for 1 or 2.5 wk to assess their migratory, proliferative, and differentiation capacities, and survival, in the embryonic gut environment. Both progenitor cell populations were transplanted in the postnatal colon of mice in vivo for 4 wk before they were analyzed for migration and differentiation using immunohistochemistry. ENS-derived progenitors migrated further than CNS-derived cells in both embryonic and postnatal gut environments. ENS-derived progenitors also gave rise to more neurons than their CNS-derived counterparts. Furthermore, neurons derived from ENS progenitors clustered together in ganglia, whereas CNS-derived neurons were mostly solitary. We conclude that, within the gut environment, ENS-derived progenitors show superior migration, proliferation, and neuronal differentiation compared with CNS progenitors. PMID:25125684

Findlay, Quan; Yap, Kiryu K; Bergner, Annette J; Young, Heather M; Stamp, Lincon A

2014-10-01

88

7 CFR 810.2201 - Definition of wheat.  

...Definition of wheat. Grain that, before the removal of dockage, consists of 50 percent or more common wheat (Triticum aestivum L.), club wheat (T. compactum Host.), and durum wheat (T. durum Desf.) and not more than 10...

2014-01-01

89

7 CFR 810.2201 - Definition of wheat.  

Code of Federal Regulations, 2011 CFR

...Definition of wheat. Grain that, before the removal of dockage, consists of 50 percent or more common wheat (Triticum aestivum L.), club wheat (T. compactum Host.), and durum wheat (T. durum Desf.) and not more than 10...

2011-01-01

90

7 CFR 810.2201 - Definition of wheat.  

Code of Federal Regulations, 2013 CFR

...Definition of wheat. Grain that, before the removal of dockage, consists of 50 percent or more common wheat (Triticum aestivum L.), club wheat (T. compactum Host.), and durum wheat (T. durum Desf.) and not more than 10...

2013-01-01

91

7 CFR 810.2201 - Definition of wheat.  

Code of Federal Regulations, 2012 CFR

...Definition of wheat. Grain that, before the removal of dockage, consists of 50 percent or more common wheat (Triticum aestivum L.), club wheat (T. compactum Host.), and durum wheat (T. durum Desf.) and not more than 10...

2012-01-01

92

Co-ordinate regulation of cytokinin gene family members during flag leaf and reproductive development in wheat  

PubMed Central

Background As the global population continues to expand, increasing yield in bread wheat is of critical importance as 20% of the world’s food supply is sourced from this cereal. Several recent studies of the molecular basis of grain yield indicate that the cytokinins are a key factor in determining grain yield. In this study, cytokinin gene family members in bread wheat were isolated from four multigene families which regulate cytokinin synthesis and metabolism, the isopentenyl transferases (IPT), cytokinin oxidases (CKX), zeatin O-glucosyltransferases (ZOG), and ?-glucosidases (GLU). As bread wheat is hexaploid, each gene family is also likely to be represented on the A, B and D genomes. By using a novel strategy of qRT-PCR with locus-specific primers shared among the three homoeologues of each family member, detailed expression profiles are provided of family members of these multigene families expressed during leaf, spike and seed development. Results The expression patterns of individual members of the IPT, CKX, ZOG, and GLU multigene families in wheat are shown to be tissue- and developmentally-specific. For instance, TaIPT2 and TaCKX1 were the most highly expressed family members during early seed development, with relative expression levels of up to 90- and 900-fold higher, respectively, than those in the lowest expressed samples. The expression of two cis-ZOG genes was sharply increased in older leaves, while an extremely high mRNA level of TaGLU1-1 was detected in young leaves. Conclusions Key genes with tissue- and developmentally-specific expression have been identified which would be prime targets for genetic manipulation towards yield improvement in bread wheat breeding programmes, utilising TILLING and MAS strategies. PMID:22672647

2012-01-01

93

Pregnancy-acquired fetal progenitor cells.  

PubMed

The transfer and persistence of fetal progenitor cells into the mother throughout pregnancy has sparked considerable interest as a trafficking stem cell and immunological phenomenon. Indeed, the intriguing longevity of semi-allogeneic fetal microchimeric cells (FMC) in parous women raises questions over their potential clinical implications. FMC have been associated with both immune-modulatory roles and participation in maternal tissue repair. Although their influence on maternal health is as yet unresolved, FMC selectively home to damaged maternal tissues and often integrate, adopting site-appropriate phenotypes. FMC features, such as plasticity and persistence in their maternal host, suggest that they likely include pluripotent, or various multipotent and committed stem and progenitor cells. Recent efforts to determine what cell types are involved have established that FMC include cells of ectodermal, endodermal, mesodermal, and perhaps trophectodermal lineages. This review details FMC phenotypes and discusses how FMC themselves may be considered a naturally occurring stem cell therapy. PMID:23432869

Seppanen, E; Fisk, N M; Khosrotehrani, K

2013-03-01

94

Prostate epithelial stem and progenitor cells  

PubMed Central

The classic androgen ablation and replacement experiment demonstrates that prostate epithelia possess extensive regenerative capacities and implies the existence of the prostate stem/progenitor cells. These cells may serve as the cells of origin for prostate cancer and their intrinsic property may dictate the clinical behaviors of the resulting diseases. Therefore, detailed characterization of these cells will potentially benefit disease prevention, diagnosis and prognosis. In this review, we describe several major in vitro and in vivo approaches that have been employed in the studies of the prostate stem cell activities, summarize the major progress that has been made during the last two decades regarding the identity of prostate stem/progenitor cells and their niches, and discuss some remaining outstanding questions in the field. PMID:25374923

Kwon, Oh-Joon; Xin, Li

2014-01-01

95

Noninvasive Imaging of Administered Progenitor Cells  

SciTech Connect

The objective of this research grant was to develop an approach for labeling progenitor cells, specifically those that we had identified as being able to replace ischemic heart cells, so that the distribution could be followed non-invasively. In addition, the research was aimed at determining whether administration of progenitor cells resulted in improved myocardial perfusion and function. The efficiency and toxicity of radiolabeling of progenitor cells was to be evaluated. For the proposed clinical protocol, subjects with end-stage ischemic coronary artery disease were to undergo a screening cardiac positron emission tomography (PET) scan using N-13 ammonia to delineate myocardial perfusion and function. If they qualified based on their PET scan, they would undergo an in-hospital protocol whereby CD34+ cells were stimulated by the administration of granulocytes-colony stimulating factor (G-CSF). CD34+ cells would then be isolated by apharesis, and labeled with indium-111 oxine. Cells were to be re-infused and subjects were to undergo single photon emission computed tomography (SPECT) scanning to evaluate uptake and distribution of labeled progenitor cells. Three months after administration of progenitor cells, a cardiac PET scan was to be repeated to evaluate changes in myocardial perfusion and/or function. Indium oxine is a radiopharmaceutical for labeling of autologous lymphocytes. Indium-111 (In-111) decays by electron capture with a t{sub ½} of 67.2 hours (2.8 days). Indium forms a saturated complex that is neutral, lipid soluble, and permeates the cell membrane. Within the cell, the indium-oxyquinolone complex labels via indium intracellular chelation. Following leukocyte labeling, ~77% of the In-111 is incorporated in the cell pellet. The presence of red cells and /or plasma reduces the labeling efficacy. Therefore, the product needed to be washed to eliminate plasma proteins. This repeated washing can damage cells. The CD34 selected product was a 90-99% pure population of leukocytes. Viability was assessed using Trypan blue histological analysis. We successfully isolated and labeled ~25-30 x 10{sup 7} CD34+ lymphocytes in cytokine mobilized progenitor cell apharesis harvests. Cells were also subjected to a stat gram stain to look for bacterial contamination, stat endotoxin LAL to look for endotoxin contamination, flow cytometry for evaluation of the purity of the cells and 14-day sterility culture. Colony forming assays confirm the capacity of these cells to proliferate and function ex-vivo with CFU-GM values of 26 colonies/ 1 x 10{sup 4} cells plated and 97% viability in cytokine augmented methylcellulose at 10-14 days in CO{sub 2} incubation. We developed a closed-processing system for the product labeling prior to infusion to maintain autologous cell integrity and sterility. Release criteria for the labeled product were documented for viability, cell count and differential, and measured radiolabel. We were successful in labeling the cells with up to 500 uCi/10{sup 8} cells, with viability of >98%. However, due to delays in getting the protocol approved by the FDA, the cells were not infused in humans in this location (although we did successfully use CD34+ cells in humans in a study in Australia). The approach developed should permit labeling of progenitor cells that can be administered to human subjects for tracking. The labeling approach should be useful for all progenitor cell types, although this would need to be verified since different cell lines may have differential radiosensitivity.

Steven R Bergmann, M.D., Ph.D.

2012-12-03

96

On the progenitors of white dwarfs  

NASA Technical Reports Server (NTRS)

Direct observational evidence is presented which indicates that the immediate progenitors of white dwarfs are the central stars of planetary nebulae (approximately 70%), other post-AGB objects (approximately 30%), and post-HB objects not massive enough to climb the AGB (approximately 0.3%). The combined birth rate for these objects is in satisfactory agreement with the death rate of main-sequence stars and the birth rate of white dwarfs.

Drilling, J. S.; Schoenberner, D.

1985-01-01

97

The genetic study utility of a hexaploid wheat DH population with non-recombinant A- and B-genomes.  

PubMed

To study the D-genome of the wild wheat relative Aegilops tauschii Cosson at the hexaploid level, we developed a synthetic doubled-haploid (DH) hexaploid wheat population, SynDH3. This population was derived from the spontaneous chromosome doubling of triploid F1 hybrid plants obtained from a cross between Triticum turgidum ssp. dicoccon PI377655 and A. tauschii ssp. strangulata AS66 × ssp. tauschii AS87. SynDH3 is a diploidization-hexaploid DH population containing recombinant D chromosomes from two different A. tauschii genotypes, with A and B chromosomes from T. turgidum being homogenous across the entire population. Using this population, we constructed a genetic map. Of the 440 markers used to construct the map, 421 (96%) were assigned to 12 linkage groups; these included 346 Diversity Arrays Technology (DArT) and 75 simple sequence repeat (SSR) markers. The total map length of the seven D chromosomes spanned 916.27 cM, with an average length of 130.90 cM per chromosome and an average distance between markers of 3.47 cM. Seven segregation distortion regions were detected on seven linkage groups. Out of 50 markers shared with those on a common wheat map, 37 showed a consistent order. The utility of the diploidization-hexaploid DH population for mapping qualitative trait genes was confirmed using the dominant glaucousness-inhibiting gene W2 (I) as an example. PMID:23577301

Hao, Ming; Chen, Jixiang; Zhang, Lianquan; Luo, Jiangtao; Yuan, Zhongwei; Yan, Zehong; Zhang, Bo; Chen, Wenjie; Wei, Yuming; Zhang, Huaigang; Zheng, Youliang; Liu, Dengcai

2013-12-01

98

Transient nuclear Prospero induces neural progenitor quiescence  

PubMed Central

Stem cells can self-renew, differentiate, or enter quiescence. Understanding how stem cells switch between these states is highly relevant for stem cell-based therapeutics. Drosophila neural progenitors (neuroblasts) have been an excellent model for studying self-renewal and differentiation, but quiescence remains poorly understood. In this study, we show that when neuroblasts enter quiescence, the differentiation factor Prospero is transiently detected in the neuroblast nucleus, followed by the establishment of a unique molecular profile lacking most progenitor and differentiation markers. The pulse of low level nuclear Prospero precedes entry into neuroblast quiescence even when the timing of quiescence is advanced or delayed by changing temporal identity factors. Furthermore, loss of Prospero prevents entry into quiescence, whereas a pulse of low level nuclear Prospero can drive proliferating larval neuroblasts into quiescence. We propose that Prospero levels distinguish three progenitor fates: absent for self-renewal, low for quiescence, and high for differentiation. DOI: http://dx.doi.org/10.7554/eLife.03363.001 PMID:25354199

Lai, Sen-Lin; Doe, Chris Q

2014-01-01

99

Applications of Suits spectral model to wheat  

NASA Technical Reports Server (NTRS)

Canopy reflectance calculations for a spring type Mexican wheat, Penjamo, are compared with published data on Scout winter wheat. Good agreement exists between model calculations and experimental data in the spectral range, 500 nm to 750 nm, suggesting that the model parameters for wheat can be applied to different cultivars of wheat in the same growth stage. Wheat canopy reflectance is dependent upon surface soil type and this dependency is examined with the Suits' spectral model. In this particular growth stage wheat reflectance is shown to be nearly independent of soil reflectance in the visible wavelengths and progressively dependent at longer wavelengths in the infrared.

Chance, J. E.

1977-01-01

100

Isolation and sequence analysis of the wheat B genome subtelomeric DNA  

PubMed Central

Background Telomeric and subtelomeric regions are essential for genome stability and regular chromosome replication. In this work, we have characterized the wheat BAC (bacterial artificial chromosome) clones containing Spelt1 and Spelt52 sequences, which belong to the subtelomeric repeats of the B/G genomes of wheats and Aegilops species from the section Sitopsis. Results The BAC library from Triticum aestivum cv. Renan was screened using Spelt1 and Spelt52 as probes. Nine positive clones were isolated; of them, clone 2050O8 was localized mainly to the distal parts of wheat chromosomes by in situ hybridization. The distribution of the other clones indicated the presence of different types of repetitive sequences in BACs. Use of different approaches allowed us to prove that seven of the nine isolated clones belonged to the subtelomeric chromosomal regions. Clone 2050O8 was sequenced and its sequence of 119 737 bp was annotated. It is composed of 33% transposable elements (TEs), 8.2% Spelt52 (namely, the subfamily Spelt52.2) and five non-TE-related genes. DNA transposons are predominant, making up 24.6% of the entire BAC clone, whereas retroelements account for 8.4% of the clone length. The full-length CACTA transposon Caspar covers 11 666 bp, encoding a transposase and CTG-2 proteins, and this transposon accounts for 40% of the DNA transposons. The in situ hybridization data for 2050O8 derived subclones in combination with the BLAST search against wheat mapped ESTs (expressed sequence tags) suggest that clone 2050O8 is located in the terminal bin 4BL-10 (0.95-1.0). Additionally, four of the predicted 2050O8 genes showed significant homology to four putative orthologous rice genes in the distal part of rice chromosome 3S and confirm the synteny to wheat 4BL. Conclusion Satellite DNA sequences from the subtelomeric regions of diploid wheat progenitor can be used for selecting the BAC clones from the corresponding regions of hexaploid wheat chromosomes. It has been demonstrated for the first time that Spelt52 sequences were involved in the evolution of terminal regions of common wheat chromosomes. Our research provides new insights into the microcollinearity in the terminal regions of wheat chromosomes 4BL and rice chromosome 3S. PMID:19732459

Salina, Elena A; Sergeeva, Ekaterina M; Adonina, Irina G; Shcherban, Andrey B; Afonnikov, Dmitry A; Belcram, Harry; Huneau, Cecile; Chalhoub, Boulos

2009-01-01

101

Heritable, De Novo Resistance to Leaf Rust and Other Novel Traits in Selfed Descendants of Wheat Responding to Inoculation with Wheat Streak Mosaic Virus  

PubMed Central

Stable resistance to infection with Wheat streak mosaic virus (WSMV) can be evolved de novo in selfing bread wheat lines subjected to cycles of WSMV inoculation and selection of best-performing plants or tillers. To learn whether this phenomenon might be applied to evolve resistance de novo to pathogens unrelated to WSMV, we examined the responses to leaf rust of succeeding generations of the rust- and WSMV-susceptible cultivar ‘Lakin’ following WSMV inoculation and derived rust-resistant sublines. After three cycles of the iterative protocol five plants, in contrast to all others, expressed resistance to leaf and stripe rust. A subset of descendant sublines of one of these, ‘R1’, heritably and uniformly expressed the new trait of resistance to leaf rust. Such sublines, into which no genes from a known source of resistance had been introgressed, conferred resistance to progeny of crosses with susceptible parents. The F1 populations produced from crosses between, respectively, susceptible and resistant ‘Lakin’ sublines 4-3-3 and 4-12-3 were not all uniform in their response to seedling inoculation with race TDBG. In seedling tests against TDBG and MKPS races the F2s from F1 populations that were uniformly resistant had 3?1 ratios of resistant to susceptible individuals but the F2s from susceptible F1 progenitors were uniformly susceptible. True-breeding lines derived from resistant individuals in F2 populations were resistant to natural stripe and leaf rust inoculum in the field, while the ‘Lakin’ progenitor was susceptible. The next generation of six of the ‘Lakin’-derived lines exhibited moderate to strong de novo resistance to stem rust races TPMK, QFCS and RKQQ in seedling tests while the ‘Lakin’ progenitor was susceptible. These apparently epigenetic effects in response to virus infection may help researchers fashion a new tool that expands the range of genetic resources already available in adapted germplasm. PMID:24497941

Seifers, Dallas L.; Haber, Steve; Martin, Terry J.; McCallum, Brent D.

2014-01-01

102

Commitment of decidual haematopoietic progenitor cells in first trimester pregnancy.  

PubMed

PROBLEM? The aim of this study was to investigate the phenotype and commitment of decidual haematopoietic progenitor cells (HPCs) in healthy pregnant women and in women with early miscarriage. METHOD OF STUDY? Peripheral blood and decidual tissue from healthy and pathological pregnant women were examined for HPCs and lymphoid progenitors using flow cytometric analysis. RESULTS? Compared with peripheral blood, we found a significant increase in decidual HPCs in both healthy pregnant women and women with spontaneous abortion. T/NK, natural killer (NK), gamma-delta and NKT cell progenitors were identified in all peripheral blood and decidual samples. In pathologic pregnant women, the ratios of decidual T/NK and NK cell progenitors were significantly increased compared with healthy pregnant controls. CONCLUSION? We demonstrated decidual cells with haematopoietic progenitor cell phenotype in human decidua. Increased levels of NK progenitors in the decidua of women with early spontaneous abortion suggest a dysregulation of this pathway that may contribute to pregnancy failure. PMID:21682790

Szereday, Laszlo; Miko, Eva; Meggyes, Matyas; Barakonyi, Aliz; Farkas, Balint; Varnagy, Akos; Bodis, Jozsef; Lynch, Lydia; O'Farrelly, Cliona; Szekeres-Bartho, Julia

2012-01-01

103

Oligodendrocyte progenitors: adult stem cells of the central nervous system?  

PubMed

Oligodendrocyte progenitors (OPs) are a major proliferating cell population within the adult CNS. In response to myelin loss or increasing demand, OPs have the capacity to differentiate into mature, myelinating oligodendrocytes. The name 'oligodendrocyte progenitor' suggests restriction to the oligodendrocyte cell lineage. However, with growing evidence of the lineage plasticity of OPs both in vitro and in vivo, we discuss whether they have potential beyond that expected of dedicated progenitor cells, and hence may justify categorization as adult stem cells. PMID:24800913

Crawford, A H; Stockley, J H; Tripathi, R B; Richardson, W D; Franklin, R J M

2014-10-01

104

Development of Pluripotent Hematopoietic Progenitor Cells in the Human Fetus  

Microsoft Academic Search

Pluripotent hematopoietic progenitor cells (CFU-GEMM), myeloid progenitor cells (CFU-GM), and erythroid progeni- tors (BFU-E) were studied in midtrimester human fetuses using the mixed colony assay. All three progenitor cell populations were detected at high levels in the fetal liver from 1 2 to 23 wk of gestation. Stem cells were first observed in the bone marrow at 1 5-1 6

I. M. Hann; M. P. Bodger; A. V. Hoffbrand

2010-01-01

105

Searching for DNA introgressed from wheat and for wheat-like grain proteins in a rice x wheat hybridization derivative  

Microsoft Academic Search

The DNA of a putative rice x wheat hybridization derivative (X Oryticum oryzoides) from China, the DNA of its parental rice cultivar and the DNA of a wheat line were digested with ten different restriction endonucleases, resolved by agarose electrophoresis, Southern blotted and hybridized using genomic wheat DNA as a probe. Phenol extracted, ethanol and cetyltrimethylammonium bromide precipitated DNA of

Hannu Ahokas

1993-01-01

106

Tissue-specific expression and localization of safener-induced glutathione S -transferase proteins in Triticum tauschii  

Microsoft Academic Search

Glutathione S-transferase (GST; EC 2.5.1.18) gene expression was examined in the coleoptile and new leaf tissue of etiolated shoots of the diploid wheat species Triticum tauschii (Coss.) Schmal., which is considered to be a progenitor and the D-genome donor to cultivated, hexaploid bread wheat Triticum aestivum L. GST expression (mRNA, protein, and enzyme activity with a herbicide substrate) in these

Dean E. Riechers; Qin Zhang; Fangxiu Xu; Kevin C. Vaughn

2003-01-01

107

Floral Transformation of Wheat  

NASA Astrophysics Data System (ADS)

A method is described for the floral transformation of wheat using a protocol similar to the floral dip of Arabidopsis. This method does not employ tissue culture of dissected embryos, but instead pre-anthesis spikes with clipped florets at the early, mid to late uninucleate microspore stage are dipped in Agrobacterium infiltration media harboring a vector carrying anthocyanin reporters and the NPTII selectable marker. T1 seeds are examined for color changes induced in the embryo by the anthocyanin reporters. Putatively transformed seeds are germinated and the seedlings are screened for the presence of the NPTII gene based on resistance to paromomycin spray and assayed with NPTII ELISAs. Genomic DNA of putative transformants is digested and analyzed on Southern blots for copy number to determine whether the T-DNA has integrated into the nucleus and to show the number of insertions. The non-optimized transformation efficiencies range from 0.3 to 0.6% (number of transformants/number of florets dipped) but the efficiencies are higher in terms of the number of transformants produced/number of seeds set ranging from 0.9 to 10%. Research is underway to maximize seed set and optimize the protocol by testing different Agrobacterium strains, visual reporters, vectors, and surfactants.

Agarwal, Sujata; Loar, Star; Steber, Camille; Zale, Janice

108

CULTIVAR DESCRIPTION CDC Kestrel winter wheat  

E-print Network

of the Canada Western Red Winter Wheat class. Key words: Triticum aestivum L., cultivar description, wheat (BAROC). Mots clés: Triticum aestivum L., description de cultivar, blé (d'automne) CDC Kestrel is a high-yielding, semidward winter wheat (Triticum aestivum L.) that was developed at the Crop Development Centre, University

Saskatchewan, University of

109

Original article Wheat gluten feed in diets  

E-print Network

Original article Wheat gluten feed in diets for intensive bull beef production * LO Fiems, CV; The use of wheat gluten feed in concentrate diets for beef bulls has been investigated in 3 experiments. Sugar-beet pulp was replaced by 15% wheat gluten feed in the first experiment and by 15, 30 or 45

Paris-Sud XI, Université de

110

WHEAT KERNEL PHYSICAL PROPERTIES AND MILLING PROCESS  

Microsoft Academic Search

A b s t r a c t . Studies concerning the relations between wheat kernel physical properties and milling properties have been carried out since the beginning of the cereal processing industry. The aim of the present work was to show the application of the most important physical properties of wheat for the evaluation of wheat technological qua lity,

Dariusz Dziki; Janusz Laskowski

111

The value of break crops for wheat  

Microsoft Academic Search

The yield of wheat growing after a broadleaf break crop generally exceeds that of wheat growing after wheat or other cereals. The presumed reasons for the yield benefit vary between break crops. They include reduced root and foliar disease, increased supply of soil water and mineral N, reduced assimilate loss to mycorrhizas, and, after legumes, growth stimulation following hydrogen gas

John Angus; Mark Peoples; John Kirkegaard; MH Ryan; L Ohlander

112

Redefining endothelial progenitor cells via clonal analysis and hematopoietic stem\\/progenitor cell principals  

Microsoft Academic Search

The limited vessel-forming capacity of infused endothelial progenitor cells (EPCs) into patients with cardiovascular dysfunction may be related to a misunder- standing of the biologic potential of the cells. EPCs are generally identified by cell surface antigen expression or counting in a commercially available kit that identi- fies \\

Mervin C. Yoder; Laura E. Mead; Daniel Prater; Theresa R. Krier; Karim N. Mroueh; Fang Li; Rachel Krasich; Constance J. Temm; Josef T. Prchal; David A. Ingram

2007-01-01

113

Removing celiac disease-related gluten proteins from bread wheat while retaining technological properties: a study with Chinese Spring deletion lines  

PubMed Central

Background Gluten proteins can induce celiac disease (CD) in genetically susceptible individuals. In CD patients gluten-derived peptides are presented to the immune system, which leads to a CD4+ T-cell mediated immune response and inflammation of the small intestine. However, not all gluten proteins contain T-cell stimulatory epitopes. Gluten proteins are encoded by multigene loci present on chromosomes 1 and 6 of the three different genomes of hexaploid bread wheat (Triticum aestivum) (AABBDD). Results The effects of deleting individual gluten loci on both the level of T-cell stimulatory epitopes in the gluten proteome and the technological properties of the flour were analyzed using a set of deletion lines of Triticum aestivum cv. Chinese Spring. The reduction of T-cell stimulatory epitopes was analyzed using monoclonal antibodies that recognize T-cell epitopes present in gluten proteins. The deletion lines were technologically tested with respect to dough mixing properties and dough rheology. The results show that removing the ?-gliadin locus from the short arm of chromosome 6 of the D-genome (6DS) resulted in a significant decrease in the presence of T-cell stimulatory epitopes but also in a significant loss of technological properties. However, removing the ?-gliadin, ?-gliadin, and LMW-GS loci from the short arm of chromosome 1 of the D-genome (1DS) removed T-cell stimulatory epitopes from the proteome while maintaining technological properties. Conclusion The consequences of these data are discussed with regard to reducing the load of T-cell stimulatory epitopes in wheat, and to contributing to the design of CD-safe wheat varieties. PMID:19351412

van den Broeck, Hetty C; van Herpen, Teun WJM; Schuit, Cees; Salentijn, Elma MJ; Dekking, Liesbeth; Bosch, Dirk; Hamer, Rob J; Smulders, Marinus JM; Gilissen, Ludovicus JWJ; van der Meer, Ingrid M

2009-01-01

114

Identifying variation in resistance to the take-all fungus, Gaeumannomyces graminis var. tritici, between different ancestral and modern wheat species  

PubMed Central

Background Ancestral wheat relatives are important sources of genetic diversity for the introduction of novel traits for the improvement of modern bread wheat. In this study the aim was to assess the susceptibility of 34 accessions of the diploid wheat Triticum monococcum (A genome) to Gaeumannomyces graminis var. tritici (Ggt), the causal agent of take-all disease. The second aim was to explore the susceptibility of tetraploid wheat (T. durum) and the B genome progenitor species Aegilops speltoides to Ggt. Results Field trials, conducted over 5 years, identified seven T. monococcum accessions with a good level of resistance to take-all when exposed to natural inoculum under UK field conditions. All other accessions were highly susceptible or did not exhibit a consistent phenotype across years. DArT marker genotyping revealed that whole genome diversity was not closely related to resistance to take-all within T. monococcum, suggesting that multiple genetic sources of resistance may exist within the species. In contrast the tetraploid wheat cultivars and Ae. speltoides were all highly susceptible to the disease, including those with known elevated levels of benzoxazinoids. Conclusions The diploid wheat species T. monococcum may provide a genetic source of resistance to take-all disease that could be utilised to improve the performance of T. aestivum in high disease risk situations. This represents an extremely valuable resource to achieve economic and sustainable genetic control of this root disease. PMID:25084989

2014-01-01

115

Pyruvate orthophosphate dikinase in wheat leaves  

SciTech Connect

Pyruvate orthophosphate dikinase (PPDK) was found in wheat (Triticum aestivum L. cv Cheyenne (CI 8885)) leaves both by activity assays and by the protein blot method. The specific activity of the wheat enzyme is comparable to that of PPDK from maize leaves. Of the total soluble protein in wheat leaves, about 0.05% was PPDK, comparable to the amount in the immature wheat seed and about 1/70th the amount found in mesophyll cells of maize. Immunoprecipitation of wheat PPDK with maize enzyme antiserum indicates partial identity, and the apparent subunit molecular weight is the same based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

Aoyagi, K.; Bassham, J.A.

1983-01-01

116

Texas Wheat Flows and Transportation Modes, 1975.  

E-print Network

was hauled by railroads, and nearly 80 percent of the wheat flowing to the Corpus Christi port was transported by railroads. Trucks were relatively more important in intrastate wheat movements (from Texas elevators to other Texas elevators or Texas flour... consistency of split on wheat received by elevators from sources - Texas elevators and out-of-state rs. For example, 99 percent of the wheat re by Northern High Plains elevators from other elevators was truck-delivered, and only 2.8 of the wheat received...

Fuller, Stephen; Paggi, Mechel; Engler, Dwayne

1977-01-01

117

Wheat in the Mediterranean revisited - tetraploid wheat landraces assessed with elite bread wheat Single Nucleotide Polymorphism markers  

PubMed Central

Background Single Nucleotide Polymorphism (SNP) panels recently developed for the assessment of genetic diversity in wheat are primarily based on elite varieties, mostly those of bread wheat. The usefulness of such SNP panels for studying wheat evolution and domestication has not yet been fully explored and ascertainment bias issues can potentially affect their applicability when studying landraces and tetraploid ancestors of bread wheat. We here evaluate whether population structure and evolutionary history can be assessed in tetraploid landrace wheats using SNP markers previously developed for the analysis of elite cultivars of hexaploid wheat. Results We genotyped more than 100 tetraploid wheat landraces and wild emmer wheat accessions, some of which had previously been screened with SSR markers, for an existing SNP panel and obtained publically available genotypes for the same SNPs for hexaploid wheat varieties and landraces. Results showed that quantification of genetic diversity can be affected by ascertainment bias but that the effects of ascertainment bias can at least partly be alleviated by merging SNPs to haplotypes. Analyses of population structure and genetic differentiation show strong subdivision between the tetraploid wheat subspecies, except for durum and rivet that are not separable. A more detailed population structure of durum landraces could be obtained than with SSR markers. The results also suggest an emmer, rather than durum, ancestry of bread wheat and with gene flow from wild emmer. Conclusions SNP markers developed for elite cultivars show great potential for inferring population structure and can address evolutionary questions in landrace wheat. Issues of marker genome specificity and mapping need, however, to be addressed. Ascertainment bias does not seem to interfere with the ability of a SNP marker system developed for elite bread wheat accessions to detect population structure in other types of wheat. PMID:24885044

2014-01-01

118

De Novo Transcriptome Assembly and Analyses of Gene Expression during Photomorphogenesis in Diploid Wheat Triticum monococcum  

PubMed Central

Background Triticum monococcum (2n) is a close ancestor of T. urartu, the A-genome progenitor of cultivated hexaploid wheat, and is therefore a useful model for the study of components regulating photomorphogenesis in diploid wheat. In order to develop genetic and genomic resources for such a study, we constructed genome-wide transcriptomes of two Triticum monococcum subspecies, the wild winter wheat T. monococcum ssp. aegilopoides (accession G3116) and the domesticated spring wheat T. monococcum ssp. monococcum (accession DV92) by generating de novo assemblies of RNA-Seq data derived from both etiolated and green seedlings. Principal Findings The de novo transcriptome assemblies of DV92 and G3116 represent 120,911 and 117,969 transcripts, respectively. We successfully mapped ?90% of these transcripts from each accession to barley and ?95% of the transcripts to T. urartu genomes. However, only ?77% transcripts mapped to the annotated barley genes and ?85% transcripts mapped to the annotated T. urartu genes. Differential gene expression analyses revealed 22% more light up-regulated and 35% more light down-regulated transcripts in the G3116 transcriptome compared to DV92. The DV92 and G3116 mRNA sequence reads aligned against the reference barley genome led to the identification of ?500,000 single nucleotide polymorphism (SNP) and ?22,000 simple sequence repeat (SSR) sites. Conclusions De novo transcriptome assemblies of two accessions of the diploid wheat T. monococcum provide new empirical transcriptome references for improving Triticeae genome annotations, and insights into transcriptional programming during photomorphogenesis. The SNP and SSR sites identified in our analysis provide additional resources for the development of molecular markers. PMID:24821410

Naithani, Sushma; Sullivan, Chris; Preece, Justin; Tiwari, Vijay K.; Elser, Justin; Leonard, Jeffrey M.; Sage, Abigail; Gresham, Cathy; Kerhornou, Arnaud; Bolser, Dan; McCarthy, Fiona; Kersey, Paul; Lazo, Gerard R.; Jaiswal, Pankaj

2014-01-01

119

PDE5 inhibitor, Vardenafil, increases circulating progenitor cells in humans  

Microsoft Academic Search

Bone marrow-derived endothelial progenitor cells (EPCs) originate from haematopoietic stem cells in bone marrow and migrate into the peripheral circulation to promote endothelial repair and neovascularization. The number of circulating progenitor cells is reduced in patients with cardiovascular risk factor. The aim of our study was to determine the number of these cells in healthy patients and to evaluate the

C Foresta; A Lana; A Cabrelle; M Ferigo; N Caretta; A Garolla; G Palù; A Ferlin

2005-01-01

120

Progenitor stem cell marker expression by pulmonary carcinomas  

Microsoft Academic Search

Carcinomas may arise as a disorder of regeneration, so that a malignant cell may represent a failure to fully attain the characteristics of differentiated tissue. We hypothesized that there is a differential distribution of progenitor cell markers among different histological types of lung cancers, with poorly differentiated tumors being more likely to express progenitor stem cell markers. The study was

Andre L Moreira; Mithat Gonen; Natasha Rekhtman; Robert J Downey

2010-01-01

121

Defining and redefining the nephron progenitor population  

PubMed Central

It has long been appreciated that the mammalian kidney arises via reciprocal interactions between an epithelial ureteric epithelium and the surrounding metanephric mesenchyme. More recently, lineage tracing has confirmed that the portion of the metanephric mesenchyme closest to the advancing ureteric tips, the cap mesenchyme, represents the progenitor population for the nephron epithelia. This Six2+Cited1+ population undergoes self-renewal throughout nephrogenesis while retaining the potential to epithelialize. In contrast, the Foxd1+ portion of the metanephric mesenchyme shows no epithelial potential, developing instead into the interstitial, perivascular, and possibly endothelial elements of the kidney. The cap mesenchyme rests within a nephrogenic niche, surrounded by the stroma and the ureteric tip. While the role of Wnt signaling in nephron induction is known, there remains a lack of clarity over the intrinsic and extrinsic regulation of cap mesenchyme specification, self-renewal, and nephron potential. It is also not known what regulates cessation of nephrogenesis, but there is no nephron generation in response to injury during the postnatal period. In this review, we will examine what is and is not known about this nephron progenitor population and discuss how an increased understanding of the regulation of this population may better explain the observed variation in final nephron number and potentially facilitate the reinitiation or prolongation of nephron formation. PMID:21229268

Hendry, Caroline; Rumballe, Bree; Moritz, Karen

2011-01-01

122

QU Carinae: a SNeIa progenitor?  

E-print Network

Optical spectra obtained in 2006-07 of the nova-like cataclysmic variable QU Car are studied for radial velocities, line profiles, and line identifications. We are not able to confirm the reported 10.9 hr orbital period from 1982,partly because our sampling is not ideal for this purpose and also, we suspect, because our radial velocities are distorted by line profile changes due to an erratic wind. P-Cygni profiles are found in several of the emission lines, including those of C IV. Carbon lines are abundant in the spectra, suggesting a carbon enrichment in the doner star. The presence of [O III] 5007\\AA and [N II] 6584\\AA is likely due to a diffuse nebula in the vicinity of the system. The wind signatures in the spectra and the presence of nebular lines are in agreement with the accretion wind evolution scenario that has been suggested to lead to SNeIa. We argue that QU Car is a member of the V Sge subclass of CVs, and a possible SNeIa progenitor. It is shown that the recent light curve of QU Car has ~1 mag low states, similar to the light curve of V Sge, strengthening the connection of QU Car with V Sge stars, supersoft x-ray sources, and SNeIa progenitors.

S. Kafka; R. Anderson; R. K. Honeycutt

2008-01-23

123

Expansion of cord blood progenitor cells.  

PubMed

Cord blood (CB) provides an alternative source of stem cells for transplantation, although in a considerable number of cases CB transplantation is followed by long periods of aplasia. Ex vivo expansion has the capacity to generate large amounts of progenitors, and it has been proposed that expanded cells might be beneficial in overcoming these long periods of aplasia. We describe the biological characteristics of cord blood compared to other sources of stem cells (BM and PB), and report the effects of FLT3-L and MIP-1alpha when added to a combination of SCF, IL-3 and IL-6 in pre-clinical short-term, serum-free expansion cultures of CB-derived CD34+ cells. After 6 days, this culture system was able to generate considerable expansion rates in the committed compartment (between 8.16- and 17.26-fold for CFU-GM, and 21.58- and 36.53-fold for the BFU-E/CFU-Mix), and the CD34+ population (between 11.25- and 25.42-fold). Moreover, this culture system was also able to maintain the week 5 CAFC population, particularly when both FLT3-L and MIP-1alpha were present (91% of the input level). Thus, we have described a pre-clinical protocol for ex vivo expansion of CB CD34+ cells in a short-term, static, serum-free system, where a high generation of committed progenitor cells is achieved together with CAFC maintenance. PMID:9712502

Querol, S; Capmany, G; Cancelas, J A; García, J

1998-06-01

124

The progenitors of supernovae Type Ia  

NASA Astrophysics Data System (ADS)

Despite the significance of Type Ia supernovae (SNeIa) in many fields in astrophysics, SNeIa lack a theoretical explanation. SNeIa are generally thought to be thermonuclear explosions of carbon/oxygen (CO) white dwarfs (WDs). The canonical scenarios involve white dwarfs reaching the Chandrasekhar mass, either by accretion from a non-degenerate companion (single-degenerate channel, SD) or by a merger of two CO WDs (double-degenerate channel, DD). The study of SNeIa progenitors is a very active field of research for binary population synthesis (BPS) studies. The strength of the BPS approach is to study the effect of uncertainties in binary evolution on the macroscopic properties of a binary population, in order to constrain binary evolutionary processes. I will discuss the expected SNeIa rate from the BPS approach and the uncertainties in their progenitor evolution, and compare with current observations. I will also discuss the results of the POPCORN project in which four BPS codes were compared to better understand the differences in the predicted SNeIa rate of the SD channel. The goal of this project is to investigate whether differences in the simulated populations are due to numerical effects or whether they can be explained by differences in the input physics. I will show which assumptions in BPS codes affect the results most and hence should be studied in more detail.

Toonen, Silvia

2014-09-01

125

Clonogenic assay of endothelial progenitor cells.  

PubMed

In stem cell biology, CD34+ or CD133+ hematopoietic stem cells (HSCs) give rise to two types of endothelial progenitor cell (EPC) colonies: primitive and definitive EPC-colony forming units (primitive EPC-CFU and definitive EPC-CFU), which can be morphologically defined. Based on their morphology, an evaluation of the number or the ratio of each EPC colony constitutes the Endothelial Progenitor Cell Clonogenic Forming Assay (EPC-CFA), a novel assay to quantify the differentiation of colony forming EPCs. This assay system allows us to practically evaluate the vasculogenic potential of primary or cultured stem cell populations, i.e., mononuclear cells or fractionated stem cells (CD34+ or CD133+ cells) in peripheral blood, bone marrow, or umbilical cord blood. EPC-CFA can be used not only for basic research in vascular biology but also for evaluating the vascular reparative activity of patients with cardiovascular diseases. This review summarizes the underlying concepts and significance of the EPC-CFA in vascular biology. PMID:23375595

Masuda, Haruchika; Asahara, Takayuki

2013-05-01

126

Constraining fast radio burst progenitors with gravitational lensing  

E-print Network

Fast Radio Bursts (FRBs) are new transient radio sources discovered recently. Because of the angular resolution restriction in radio surveys, no optical counter part has been identified yet so it is hard to determine the progenitor of FRBs. In this paper we propose to use radio lensing survey to constrain FRB progenitors. We show that, different types of progenitors lead to different probabilities for a FRB to be gravitationally lensed by dark matter halos in foreground galaxies, since different type progenitors result in different redshift distributions of FRBs. For example, the redshift distribution of FRBs arising from double stars shifts toward lower redshift than of the FRBs arising from single stars, because double stars and single stars have different evolution timescales. With detailed calculations, we predict that the FRB sample size for producing one lensing event varies significantly for different FRB progenitor models. We argue that this fact can be used to distinguish different FRB models and als...

Li, Chun-Yu

2014-01-01

127

Temporal Fate Specification and Neural Progenitor Competence During Development  

PubMed Central

The vast diversity of neurons and glia of the central nervous system is generated from a small, heterogeneous population of progenitors that undergo transcriptional changes during development to sequentially specify distinct cell fates. Guided by cell intrinsic and temporal extrinsic cues, invertebrate and mammalian neural progenitors carefully regulate when and how many of each cell type is produced to form functional neural circuits. Emerging evidence indicates that neural progenitors also undergo changes in global chromatin architecture, thereby restricting the duration a particular temporal cue can act. Thus, studies of temporal identity specification and progenitor competence can provide insight into how we may use neural progenitors to more effectively generate specific cell types for brain repair. PMID:24400340

Kohwi, Minoree; Doe, Chris Q.

2014-01-01

128

Mast cell progenitors: origin, development and migration to tissues.  

PubMed

Mast cells in tissues are developed from mast cell progenitors emerging from the bone marrow in a process highly regulated by transcription factors. Through the advancement of the multicolor flow cytometry technique, the mast cell progenitor population in the mouse has been characterized in terms of surface markers. However, only cell populations with enriched mast cell capability have been described in human. In naïve mice, the peripheral tissues have a constitutive pool of mast cell progenitors. Upon infections in the gut and in allergic inflammation in the lung, the local mast cell progenitor numbers increase tremendously. This review focuses on the origin and development of mast cell progenitors. Furthermore, the evidences for cells and molecules that govern the migration of these cells in mice in vivo are described. PMID:24598075

Dahlin, Joakim S; Hallgren, Jenny

2015-01-01

129

Phytochemical and pharmacological perspectives of wheat grain and lupin seed  

Microsoft Academic Search

Wheat and lupin are important crops grown in Australia with massive production every year. Traditionally, both wheat and lupin have been consumed as human foods for their health benefits, which may be due in part to the biologically active phytochemicals they contain. This thesis describes the phytochemical and pharmacological investigations of wheat bran, different wheat bran layers, wheat germ, lupin

Lei Liu

2009-01-01

130

Mechanistic analysis of wheat chlorophyllase  

Microsoft Academic Search

Chlorophyllase catalyzes the initial step in the degradation of chlorophyll and plays a key role in leaf senescence and fruit ripening. Here, we report the cloning of chlorophyllase from Triticum aestivum (wheat) and provide a detailed mechanistic analysis of the enzyme. Purification of recombinant chlorophyllase from an Escherichia coli expression system indicates that the enzyme functions as a dimeric protein.

Kiani A. J. Arkus; Edgar B. Cahoon; Joseph M. Jez

2005-01-01

131

The Progenitor of SN 1987A. [IUE  

NASA Technical Reports Server (NTRS)

Spatially resolved IUE spectra (1150 to 2000 A) taken at the position of SN 1987A in March 1987 show that the 12th mag B3 I star Sk -69 deg 202 disappeared. Only the fainter companion stars (Star 2 and Star 3) are present near the site of the supernova. It is concluded that Sk -69 deg 202 exploded to produce SN 1987A. The known characteristics of Sk -69 deg 202 are consistent with the interpretation that the progenitor was a relatively compact star, having a high-velocity low-density stellar wind prior to the outburst. Recent IUE spectra of SN 1987A (May 1988) show no evidence that Sk -69 deg 202 still exists inside the expanding ejecta.

Sonneborn, G.

1988-01-01

132

New approaches to SNe Ia progenitors  

E-print Network

Although Type Ia supernovae (SNe Ia) are a major tool in cosmology and play a key role in the chemical evolution of galaxies, the nature of their progenitor systems (apart from the fact that they must be close binaries containing at least one white dwarf) remains largely unknown. In the last decade, considerable efforts have been made, both observationally and theoretically, to solve this problem. Observations have, however, revealed a previously unsuspected variety of events, ranging from very underluminous outbursts to clearly overluminous ones, and spanning a range well outside the peak luminosity--decline rate of the light curve relationship, used to make calibrated candles of the SNe Ia. On the theoretical side, new explosion scenarios, such as violent mergings of pairs of white dwarfs, have been explored. We review those recent developments, emphasizing the new observational findings, but also trying to tie them to the different scenarios and explosion mechanisms proposed thus far.

Ruiz-Lapuente, Pilar

2014-01-01

133

New approaches to SNe Ia progenitors  

NASA Astrophysics Data System (ADS)

Although Type Ia supernovae (SNe Ia) are a major tool in cosmology and play a key role in the chemical evolution of galaxies, the nature of their progenitor systems (apart from the fact that they must content at least one white dwarf, that explodes) remains largely unknown. In the last decade, considerable efforts have been made, both observationally and theoretically, to solve this problem. Observations have, however, revealed a previously unsuspected variety of events, ranging from very underluminous outbursts to clearly overluminous ones, and spanning a range well outside the peak luminosity-decline rate of the light curve relationship, used to make calibrated candles of the SNe Ia. On the theoretical side, new explosion scenarios, such as violent mergings of pairs of white dwarfs, have been explored. We review those recent developments, emphasizing the new observational findings, but also trying to tie them to the different scenarios and explosion mechanisms proposed thus far.

Ruiz-Lapuente, Pilar

2014-10-01

134

PET imaging of adoptive progenitor cell therapies.  

SciTech Connect

Objectives. The overall objective of this application is to develop novel technologies for non-invasive imaging of adoptive stem cell-based therapies with positron emission tomography (PET) that would be applicable to human patients. To achieve this objective, stem cells will be genetically labeled with a PET-reporter gene and repetitively imaged to assess their distribution, migration, differentiation, and persistence using a radiolabeled reporter probe. This new imaging technology will be tested in adoptive progenitor cell-based therapy models in animals, including: delivery pro-apoptotic genes to tumors, and T-cell reconstitution for immunostimulatory therapy during allogeneic bone marrow progenitor cell transplantation. Technical and Scientific Merits. Non-invasive whole body imaging would significantly aid in the development and clinical implementation of various adoptive progenitor cell-based therapies by providing the means for non-invasive monitoring of the fate of injected progenitor cells over a long period of observation. The proposed imaging approaches could help to address several questions related to stem cell migration and homing, their long-term viability, and their subsequent differentiation. The ability to image these processes non-invasively in 3D and repetitively over a long period of time is very important and will help the development and clinical application of various strategies to control and direct stem cell migration and differentiation. Approach to accomplish the work. Stem cells will be genetically with a reporter gene which will allow for repetitive non-invasive “tracking” of the migration and localization of genetically labeled stem cells and their progeny. This is a radically new approach that is being developed for future human applications and should allow for a long term (many years) repetitive imaging of the fate of tissues that develop from the transplanted stem cells. Why the approach is appropriate. The novel approach to stem cell imaging is proposed to circumvent the major limitation of in vitro radiolabeling – the eventual radiolabel decay. Stable transduction of stem cells in vitro would allow for the selection of high quality stem cells with optimal functional parameters of the transduced reporter systems. The use of a long-lived radioisotope 124I to label a highly specific reporter gene probe will allow for ex vivo labeling of stem cells and their imaging immediately after injection and during the following next week. The use of short-lived radioisotopes (i.e., 18F) to label highly specific reporter gene probes will allow repetitive PET imaging for the assessment of to stem cell migration, targeting, differentiation, and long-term viability of stem cell-derived tissues. Qualifications of the research team and resources. An established research team of experts in various disciplines has been assembled at MD Anderson Cancer Center (MDACC) over the past two years including the PI, senior co-investigators and collaborators. The participants of this team are recognized internationally to be among the leaders in their corresponding fields of research and clinical medicine. The resources at MDACC are exceptionally well developed and have been recently reinforced by the installation of a microPET and microSPECT/CT cameras, and a 7T MRI system for high resolution animal imaging; and by integrating a synthetic chemistry core for the development and production of precursors for radiolabeling.

Gelovani, Juri G.

2008-05-13

135

Direct Transcriptional Reprogramming of Adult Cells to Embryonic Nephron Progenitors  

PubMed Central

Direct reprogramming involves the enforced re-expression of key transcription factors to redefine a cellular state. The nephron progenitor population of the embryonic kidney gives rise to all cells within the nephron other than the collecting duct through a mesenchyme-to-epithelial transition, but this population is exhausted around the time of birth. Here, we sought to identify the conditions under which adult proximal tubule cells could be directly transcriptionally reprogrammed to nephron progenitors. Using a combinatorial screen for lineage-instructive transcription factors, we identified a pool of six genes (SIX1, SIX2, OSR1, EYA1, HOXA11, and SNAI2) that activated a network of genes consistent with a cap mesenchyme/nephron progenitor phenotype in the adult proximal tubule (HK2) cell line. Consistent with these reprogrammed cells being nephron progenitors, we observed differential contribution of the reprogrammed population into the Six2+ nephron progenitor fields of an embryonic kidney explant. Dereplication of the pool suggested that SNAI2 can suppress E-CADHERIN, presumably assisting in the epithelial-to-mesenchymal transition (EMT) required to form nephron progenitors. However, neither TGF?-induced EMT nor SNAI2 overexpression alone was sufficient to create this phenotype, suggesting that additional factors are required. In conclusion, these results suggest that reinitiation of kidney development from a population of adult cells by generating embryonic progenitors may be feasible, opening the way for additional cellular and bioengineering approaches to renal repair and regeneration. PMID:23766537

Hendry, Caroline E.; Vanslambrouck, Jessica M.; Ineson, Jessica; Suhaimi, Norseha; Takasato, Minoru; Rae, Fiona

2013-01-01

136

Identification of functional progenitor cells in the pulmonary vasculature  

PubMed Central

The pulmonary vasculature comprises a complex network of branching arteries and veins all functioning to reoxygenate the blood for circulation around the body. The cell types of the pulmonary artery are able to respond to changes in oxygen tension in order to match ventilation to perfusion. Stem and progenitor cells in the pulmonary vasculature are also involved, be it in angiogenesis, endothelial dysfunction or formation of vascular lesions. Stem and progenitor cells may be circulating around the body, residing in the pulmonary artery wall or stimulated for release from a central niche like the bone marrow and home to the pulmonary vasculature along a chemotactic gradient. There may currently be some controversy over the pathogenic versus therapeutic roles of stem and progenitor cells and, indeed, it is likely both chains of evidence are correct due to the specific influence of the immediate environmental niche a progenitor cell may be in. Due to their great plasticity and a lack of specific markers for stem and progenitor cells, they can be difficult to precisely identify. This review discusses the methodological approaches used to validate the presence of and subtype of progenitors cells in the pulmonary vasculature while putting it in context of the current knowledge of the therapeutic and pathogenic roles for such progenitor cells. PMID:22558524

Firth, Amy L.; Yuan, Jason X. -J.

2012-01-01

137

Synthetic Hexaploid Wheat as a Source of Improvement for Winter Wheat (Triticum aestivum L.) in Texas  

E-print Network

of this research was to evaluate the potential and performance of synthetic wheat in Texas. Ten elite primary synthetics from the International Maize and Wheat Improvement Center (CIMMYT), screened for desirable traits, were backcrossed to two Texas cultivars, TAM...

Cooper, Jessica Kay

2012-02-14

138

Intrinsic karyotype stability and gene copy number variations may have laid the foundation for tetraploid wheat formation  

PubMed Central

Polyploidy or whole-genome duplication is recurrent in plant evolution, yet only a small fraction of whole-genome duplications has led to successful speciation. A major challenge in the establishment of nascent polyploids is sustained karyotype instability, which compromises fitness. The three putative diploid progenitors of bread wheat, with AA, SS (S ? B), and DD genomes occurred sympatrically, and their cross-fertilization in different combinations may have resulted in fertile allotetraploids with various genomic constitutions. However, only SSAA or closely related genome combinations have led to the speciation of tetraploid wheats like Triticum turgidum and Triticum timopheevii. We analyzed early generations of four newly synthesized allotetraploid wheats with genome compositions SshSshAmAm, SlSlAA, SbSbDD, and AADD by combined fluorescence and genomic in situ hybridization-based karyotyping. Results of karyotype analyses showed that although SshSshAmAm and SlSlAA are characterized by immediate and persistent karyotype stability, massive aneuploidy and extensive chromosome restructuring are associated with SbSbDD and AADD in which parental subgenomes showed markedly different propensities for chromosome gain/loss and rearrangements. Although compensating aneuploidy and reciprocal translocation between homeologs prevailed, reproductive fitness was substantially compromised due to chromosome instability. Strikingly, localized genomic changes in repetitive DNA and copy-number variations in gene homologs occurred in both chromosome stable lines, SshSshAmAm and SlSlAA. Our data demonstrated that immediate and persistent karyotype stability is intrinsic to newly formed allotetraploid wheat with genome combinations analogous to natural tetraploid wheats. This property, coupled with rapid gene copy-number variations, may have laid the foundation of tetraploid wheat establishment. PMID:24218593

Zhang, Huakun; Bian, Yao; Gou, Xiaowan; Dong, Yuzhu; Rustgi, Sachin; Zhang, Bangjiao; Xu, Chunming; Li, Ning; Qi, Bao; Han, Fangpu; von Wettstein, Diter; Liu, Bao

2013-01-01

139

Intrinsic karyotype stability and gene copy number variations may have laid the foundation for tetraploid wheat formation.  

PubMed

Polyploidy or whole-genome duplication is recurrent in plant evolution, yet only a small fraction of whole-genome duplications has led to successful speciation. A major challenge in the establishment of nascent polyploids is sustained karyotype instability, which compromises fitness. The three putative diploid progenitors of bread wheat, with AA, SS (S ? B), and DD genomes occurred sympatrically, and their cross-fertilization in different combinations may have resulted in fertile allotetraploids with various genomic constitutions. However, only SSAA or closely related genome combinations have led to the speciation of tetraploid wheats like Triticum turgidum and Triticum timopheevii. We analyzed early generations of four newly synthesized allotetraploid wheats with genome compositions S(sh)S(sh)A(m)A(m), S(l)S(l)AA, S(b)S(b)DD, and AADD by combined fluorescence and genomic in situ hybridization-based karyotyping. Results of karyotype analyses showed that although S(sh)S(sh)A(m)A(m) and S(l)S(l)AA are characterized by immediate and persistent karyotype stability, massive aneuploidy and extensive chromosome restructuring are associated with S(b)S(b)DD and AADD in which parental subgenomes showed markedly different propensities for chromosome gain/loss and rearrangements. Although compensating aneuploidy and reciprocal translocation between homeologs prevailed, reproductive fitness was substantially compromised due to chromosome instability. Strikingly, localized genomic changes in repetitive DNA and copy-number variations in gene homologs occurred in both chromosome stable lines, S(sh)S(sh)A(m)A(m) and S(l)S(l)AA. Our data demonstrated that immediate and persistent karyotype stability is intrinsic to newly formed allotetraploid wheat with genome combinations analogous to natural tetraploid wheats. This property, coupled with rapid gene copy-number variations, may have laid the foundation of tetraploid wheat establishment. PMID:24218593

Zhang, Huakun; Bian, Yao; Gou, Xiaowan; Dong, Yuzhu; Rustgi, Sachin; Zhang, Bangjiao; Xu, Chunming; Li, Ning; Qi, Bao; Han, Fangpu; von Wettstein, Diter; Liu, Bao

2013-11-26

140

19 CFR 19.32 - Wheat manipulation; reconditioning.  

Code of Federal Regulations, 2011 CFR

...Duties 1 2011-04-01 2011-04-01 false Wheat manipulation; reconditioning. 19.32 Section 19.32 Customs...Space Bonded for the Storage of Wheat § 19.32 Wheat manipulation; reconditioning. (a) The mixing,...

2011-04-01

141

Many roads, one destination for T cell progenitors.  

PubMed

The thymus manufactures new T cells throughout life but contains no self-renewing potential. Instead, replenishment depends on recruitment of bone marrow-derived progenitors that circulate in the blood. Attempts to identify thymic-homing progenitors, and to assess the degree to which they are precommitted to the T cell lineage, have led to complex and sometimes conflicting results. As described here, this probably reflects the existence of multiple distinct types of T cell lineage progenitors as well as differences in individual experimental approaches. PMID:15983068

Petrie, Howard T; Kincade, Paul W

2005-07-01

142

Study of wheat protein based materials  

NASA Astrophysics Data System (ADS)

Wheat gluten is a naturally occurring protein polymer. It is produced in abundance by the agricultural industry, is biodegradable and very inexpensive (less than $0.50/lb). It has unique viscoelastic properties, which makes it a promising alternative to synthetic plastics. The unplasticized wheat gluten is, however, brittle. Plasticizers such as glycerol are commonly used to give flexibility to the articles made of wheat gluten but with the penalty of greatly reduced stiffness. Former work showed that the brittleness of wheat gluten can also be improved by modifying it with a tri-thiol additive with no penalty of reduced stiffness. However, the cost of the customer designed tri-thiol additive was very high and it was unlikely to make a cost effective material from such an expensive additive. Here we designed a new, inexpensive thiol additive called SHPVA. It was synthesized from polyvinyl alcohol (PVA) through a simple esterification reaction. The mechanical data of the molded wheat gluten/SHPVA material indicated that wheat gluten was toughened by SHPVA. As a control, the wheat gluten/PVA material showed no improvement compared with wheat gluten itself. Several techniques have been used to characterize this novel protein/polymer blend. Differential scanning calorimetric (DSC) study showed two phases in both wheat gluten/PVA and wheat gluten/SHPVA material. However, scanning electron microscope (SEM) pictures indicated that PVA was macroscopically separated from wheat gluten, while wheat gluten/SHPVA had a homogeneous look. The phase image from the atomic force microscope (AFM) gave interesting contrast based on the difference in the mechanical properties of these two phases. The biodegradation behavior of these protein/polymer blends was examined in soil. SHPVA was not degraded in the time period of the experiment. Wheat gluten/SHPVA degraded slower than wheat gluten. We also developed some other interesting material systems based on wheat gluten, including the wheat gluten/basalt composite and wheat gluten/clay composite materials. Their mechanical properties and biodegradation behaviors were determined.

Ye, Peng

143

Population divergence in the wheat leaf rust fungus Puccinia triticina is correlated with wheat evolution.  

PubMed

Co-evolution of fungal pathogens with their host species during the domestication of modern crop varieties has likely affected the current genetic divergence of pathogen populations. The objective of this study was to determine if the evolutionary history of the obligate rust pathogen on wheat, Puccinia triticina, is correlated with adaptation to hosts with different ploidy levels. Sequence data from 15 loci with different levels of polymorphism were generated. Phylogenetic analyses (parsimony, Bayesian, maximum likelihood) showed the clear initial divergence of P. triticina isolates collected from Aegilops speltoides (the likely B genome donor of modern wheat) in Israel from the other isolates that were collected from tetraploid (AB genomes) durum wheat and hexaploid (ABD genomes) common wheat. Coalescence-based genealogy samplers also indicated that P. triticina on A. speltoides, diverged initially, followed by P. triticina isolates from durum wheat in Ethiopia and then by isolates from common wheat. Isolates of P. triticina found worldwide on cultivated durum wheat were the most recently coalesced and formed a clade nested within the isolates from common wheat. By a relative time scale, the divergence of P. triticinia as delimited by host specificity appears very recent. Significant reciprocal gene flow between isolates from common wheat and isolates from durum wheat that are found worldwide was detected, in addition to gene flow from isolates on common wheat to isolates on durum wheat in Ethiopia. PMID:24301080

Liu, M; Rodrigue, N; Kolmer, J

2014-04-01

144

Impact of United States international wheat policy  

E-print Network

, an accord, along the lines of an international wheat agreement, appears possible. Poorer importing countries stress that such an agreement should be This thesis is consistent in format and style with Reutlinger, S. A Simulation Eodel for Evaluating..., for instance, is currently offering new incentives to its wheat producers and has raised stockholding objectives. One factor underlying stalemated efforts at achieving a successful new international wheat agreement is the fundamental deaand...

Richards, Dean

2012-06-07

145

Segmentation and tracking of neural progenitor cells in  

E-print Network

Segmentation and tracking of neural progenitor cells in microscopic image sequences John Christian and Mathematical Modelling Building 321, DK-2800 Kongens Lyngby, Denmark Phone +45 45253351, Fax +45 45882673

146

Transcriptome Analysis Identifies Regulators of Hematopoietic Stem and Progenitor Cells  

E-print Network

Hematopoietic stem cells (HSCs) maintain blood homeostasis and are the functional units of bone marrow transplantation. To improve the molecular understanding of HSCs and their proximal progenitors, we performed transcriptome ...

Gazit, Roi

147

Formation and evolution of hypernova progenitors in massive binary systems  

E-print Network

The massive stellar progenitor of a hypernova explosion and an associated gamma-ray burst must satisfy two primary constraints: (1) the outer layers of the stellar core must possess sufficient angular momentum to form a ...

Becker, John Alex, 1964-

2004-01-01

148

Neurobiology of Disease Oligodendroglial Progenitor Cell Therapy Limits  

E-print Network

, 20133 Milano, Italy This work describes the first successful oligodendrocyte-based cell therapy (MLD). We found that oligodendrocyte progenitors (OLPs) engrafted and survived into adulthood when, and survived as proteolipid protein- and MBP-positive postmitotic myelinating oligodendrocytes (OLs

Bongarzone, Ernesto R.

149

The Adventitia: A Progenitor Cell Niche for the Vessel Wall  

PubMed Central

Recent observations suggest that the adventitial layer of blood vessels exhibits properties resembling a stem/progenitor cell niche. Progenitor cells have been isolated from the adventitia of both murine and human blood vessels with the potential to form endothelial cells, mural cells, osteogenic cells, and adipocytes. These progenitors appear to cluster at or near the border zone between the outer media and inner adventitia. In the mouse, this border zone region corresponds to a localized site of sonic hedgehog signaling in the artery wall. This brief review will discuss the emerging evidence that the tunica adventitia may provide a niche-like signaling environment for resident progenitor cells and will address the role of the adventitia in growth, remodeling, and repair of the artery wall. PMID:22005572

Majesky, Mark W.; Dong, Xiu Rong; Hoglund, Virginia; Daum, Gunter; Mahoney, William M.

2011-01-01

150

Myogenic differentiation of embryonic derived mesoderm progenitor cells  

E-print Network

al. “Mesenchymal Stem Cells: Emerging therapy for DuchenneStem and progenitor cells in skeletal muscle development, maintenance, and therapy.stem cells to differentiate into any cell type provides a potential therapy

Gadde, Manasa

2011-01-01

151

Implanted adipose progenitor cells as physicochemical regulators of breast cancer  

E-print Network

Implanted adipose progenitor cells as physicochemical regulators of breast cancer Emily M for review January 2, 2012) Multipotent adipose-derived stem cells (ASCs) are increasingly used that soluble factors from breast cancer cells inhibit adipogenic differentiation while increasing proliferation

Cohen, Itai

152

Achieving yield gains in wheat.  

PubMed

Wheat provides 20% of calories and protein consumed by humans. Recent genetic gains are <1% per annum (p.a.), insufficient to meet future demand. The Wheat Yield Consortium brings expertise in photosynthesis, crop adaptation and genetics to a common breeding platform. Theory suggest radiation use efficiency (RUE) of wheat could be increased ~50%; strategies include modifying specificity, catalytic rate and regulation of Rubisco, up-regulating Calvin cycle enzymes, introducing chloroplast CO(2) concentrating mechanisms, optimizing light and N distribution of canopies while minimizing photoinhibition, and increasing spike photosynthesis. Maximum yield expression will also require dynamic optimization of source: sink so that dry matter partitioning to reproductive structures is not at the cost of the roots, stems and leaves needed to maintain physiological and structural integrity. Crop development should favour spike fertility to maximize harvest index so phenology must be tailored to different photoperiods, and sensitivity to unpredictable weather must be modulated to reduce conservative responses that reduce harvest index. Strategic crossing of complementary physiological traits will be augmented with wide crossing, while genome-wide selection and high throughput phenotyping and genotyping will increase efficiency of progeny screening. To ensure investment in breeding achieves agronomic impact, sustainable crop management must also be promoted through crop improvement networks. PMID:22860982

Reynolds, Matthew; Foulkes, John; Furbank, Robert; Griffiths, Simon; King, Julie; Murchie, Erik; Parry, Martin; Slafer, Gustavo

2012-10-01

153

Chromosome pairing of individual genomes in tall fescue (Festuca arundinacea Schreb.), its progenitors, and hybrids with Italian ryegrass (Lolium multiflorum Lam.).  

PubMed

A diploid-like pairing system prevents meiotic irregularities and improves the efficiency of gamete production in allopolyploid species. While the nature of the system is known in some polyploid crops including wheat, little is known about the control of chromosome pairing in polyploid fescues (Festuca spp.). In this work we studied chromosome pairing in allohexaploid F. arundinacea, its progenitors F. pratensis and F. glaucescens, and two intergeneric hybrids Lolium multiflorum (2x) x F. arundinacea (6x) and L. multiflorum (4x) x F. glaucescens (4x). The use of genomic in situ hybridization (GISH) permitted the analysis of homoeologous chromosome pairing and recombination of different genomes involved. We detected a diploid-like pairing system in polyploid fescues F. arundinacea and F. glaucescens, the latter being one of the progenitors of F. arundinacea. The pairing control system was absent in the second progenitor F. pratensis. Detailed analysis of intergeneric hybrids confirmed the presumed haploinsufficiency of the fescue system, which resulted in homoeologous pairing between all component genomes. This indicates that introgression of any specific chromosome segment from one genome to another is possible in all genome combinations. Our results not only contribute to the quest to discover the nature of the system controlling chromosome pairing in polyploid fescues, but may also have serious implications for design of hybrid breeding schemes in forage grasses. PMID:19420930

Kopecký, D; Bartos, J; Zwierzykowski, Z; Dolezel, J

2009-01-01

154

A comprehensive methylome map of lineage commitment from hematopoietic progenitors  

PubMed Central

Epigenetic modifications must underlie lineage-specific differentiation as terminally differentiated cells express tissue-specific genes, but their DNA sequence is unchanged. Hematopoiesis provides a well-defined model to study epigenetic modifications during cell-fate decisions, as multipotent progenitors (MPPs) differentiate into progressively restricted myeloid or lymphoid progenitors. While DNA methylation is critical for myeloid versus lymphoid differentiation, as demonstrated by the myeloerythroid bias in Dnmt1 hypomorphs1, a comprehensive DNA methylation map of hematopoietic progenitors, or of any multipotent/oligopotent lineage, does not exist. Here we examined 4.6 million CpG sites throughout the genome for MPPs, common lymphoid progenitors (CLPs), common myeloid progenitors (CMPs), granulocyte/macrophage progenitors (GMPs), and thymocyte progenitors (DN1, DN2, DN3). Dramatic epigenetic plasticity accompanied both lymphoid and myeloid restriction. Myeloid commitment involved less global DNA methylation than lymphoid commitment, supported functionally by myeloid skewing of progenitors following treatment with a DNA methyltransferase inhibitor. Differential DNA methylation correlated with gene expression more strongly at CpG island shores than CpG islands. Many examples of genes and pathways not previously known to be involved in choice between lymphoid/myeloid differentiation have been identified, such as Arl4c and Jdp2. Several transcription factors, including Meis1, were methylated and silenced during differentiation, suggesting a role in maintaining an undifferentiated state. Additionally, epigenetic modification of modifiers of the epigenome appears to be important in hematopoietic differentiation. Our results directly demonstrate that modulation of DNA methylation occurs during lineage-specific differentiation and defines a comprehensive map of the methylation and transcriptional changes that accompany myeloid versus lymphoid fate decisions. PMID:20720541

Ji, Hong; Ehrlich, Lauren I. R.; Seita, Jun; Murakami, Peter; Doi, Akiko; Lindau, Paul; Lee, Hwajin; Aryee, Martin J.; Irizarry, Rafael A.; Kim, Kitai; Rossi, Derrick J; Inlay, Matthew A.; Serwold, Thomas; Karsunky, Holger; Ho, Lena; Daley, George Q.; Weissman, Irving L.; Feinberg, Andrew P.

2010-01-01

155

The Role of Progenitor Cells in Lung Disease Prognosis  

Microsoft Academic Search

\\u000a The number of investigations related to the role of stem and progenitor cells in lung repair has grown exponentially in recent\\u000a years. Bone-marrow-derived cells, including stem cells and progenitors, have emerged as candidate markers to prognosticate\\u000a outcomes during pulmonary disease. The relationship of these cells to prognosis has provided clues regarding the pathophysiologic\\u000a characteristics of pulmonary disease, and direction for

Ellen L. Burnham; Susan Majka; Marc Moss

156

Reprogramming diabetic stem or progenitor cells for treating diabetic complications  

Cancer.gov

Bone marrow-derived stem or progenitor cells such as mesenchymal stem cells (MSCs) or endothelial progenitor cells (EPCs) have been shown to be effective for repairing cardiovascular disease. However, recent studies have shown that autologous cells derived from diabetic patients are not as effective as those from non-diabetic or healthy volunteers. As many cardiovascular disease patients who are candidate for cell therapy have diabetes as co-morbid condition, new measures are required to reverse their dysfunction.

157

Cyclin D2 controls B cell progenitor numbers  

Microsoft Academic Search

Cyclin D2 affects B cell proliferation and differentiation in vivo. It is rate-limiting for B cell receptor (BCR)-dependent proliferation of B cells, and cyclin D2\\/ mice lack CD5(B1) B lymphocytes. We show here that the bone marrow (BM) of cyclin D2\\/ mice contains half the num- bers of Sca1B220 B cell progenitors but nor- mal levels of Sca1 progenitor cells

Azim Mohamedali; Ines Soeiro; Nicholas C. Lea; Janet Glassford; Lolita Banerji; Ghulam J. Mufti; Eric W.-F. Lam; N. Shaun; B. Thomas

2003-01-01

158

SOX2 Functions to Maintain Neural Progenitor Identity  

Microsoft Academic Search

Neural progenitors of the vertebrate CNS are defined by generic cellular characteristics, including their pseudoepithelial morphology and their ability to divide and differentiate. SOXB1 transcription factors, including the three closely related genes Sox1, Sox2, and Sox3, universally mark neural progenitor and stem cells throughout the vertebrate CNS. We show here that constitutive expression of SOX2 inhibits neuronal differentiation and results

Victoria Graham; Jane Khudyakov; Pamela Ellis; Larysa Pevny

2003-01-01

159

Comprehensive methylome map of lineage commitment from haematopoietic progenitors  

Microsoft Academic Search

Epigenetic modifications must underlie lineage-specific differentiation as terminally differentiated cells express tissue-specific genes, but their DNA sequence is unchanged. Haematopoiesis provides a well-defined model to study epigenetic modifications during cell-fate decisions, as multipotent progenitors (MPPs) differentiate into progressively restricted myeloid or lymphoid progenitors. Although DNA methylation is critical for myeloid versus lymphoid differentiation, as demonstrated by the myeloerythroid bias in

Hong Ji; Lauren I. R. Ehrlich; Jun Seita; Peter Murakami; Akiko Doi; Paul Lindau; Hwajin Lee; Martin J. Aryee; Rafael A. Irizarry; Kitai Kim; Derrick J. Rossi; Matthew A. Inlay; Thomas Serwold; Holger Karsunky; Lena Ho; George Q. Daley; Irving L. Weissman; Andrew P. Feinberg

2010-01-01

160

Isolation of Human Oral Keratinocyte Progenitor\\/Stem Cells  

Microsoft Academic Search

Progenitor\\/stem cell populations of epithelium are known to reside in the small-sized cell population. Our objective was to physically isolate and characterize an oral keratinocyte-enriched population of small-sized progenitor\\/stem cells. Primary human oral mucosal keratinocytes cultured in a chemically defined serum-free culture system, devoid of animal-derived feeder cells, were sorted by relative cell size and characterized by immunolabeling for ?1

K. Izumi; T. Tobita; S. E. Feinberg

2007-01-01

161

MiR-223 deficiency increases eosinophil progenitor proliferation  

PubMed Central

Recently, microRNAs (miRNAs) have been shown to be involved in hematopoietic cell development but their role in eosinophilopoeisis has not yet been described. Here we show that miR-223 is up-regulated during eosinophil differentiation in an ex vivo bone marrow derived eosinophil culture system. Targeted ablation of miR-223 leads to an increased proliferation of eosinophil progenitors. We found up-regulation of a miR-223 target gene – IGF1R in the eosinophil progenitor cultures derived from miR-223-/- mice compared to miR-223+/+ littermate controls. The increased proliferation of miR-223-/- eosinophil progenitors was reversed by treatment with the IGF1R inhibitor (picropodophyllin). Whole genome microarray analysis of differentially regulated genes between miR-223+/+ and miR-223-/- eosinophil progenitor cultures identified a specific enrichment in genes that regulate hematologic cell development. Indeed, miR-223-/- eosinophil progenitors had a delay in differentiation. Our results demonstrate that miRNAs regulate the development of eosinophils by influencing eosinophil progenitor growth and differentiation and identify a contributory role for miR-223 in this process. PMID:23325891

Lu, Thomas X.; Lim, Eun-Jin; Besse, John A.; Itskovich, Svetlana; Plassard, Andrew J.; Fulkerson, Patricia C.; Aronow, Bruce J.; Rothenberg, Marc E.

2012-01-01

162

Constraining fast radio burst progenitors with gravitational lensing  

NASA Astrophysics Data System (ADS)

Fast Radio Bursts (FRBs) are new transient radio sources discovered recently. Because of the angular resolution restriction in radio surveys, no optical counter part has been identified yet so it is hard to determine the progenitor of FRBs. In this paper we propose to use radio lensing survey to constrain FRB progenitors. We show that, different types of progenitors lead to different probabilities for a FRB to be gravitationally lensed by dark matter halos in foreground galaxies, since different type progenitors result in different redshift distributions of FRBs. For example, the redshift distribution of FRBs arising from double stars shifts toward lower redshift than of the FRBs arising from single stars, because double stars and single stars have different evolution timescales. With detailed calculations, we predict that the FRB sample size for producing one lensing event varies significantly for different FRB progenitor models. We argue that this fact can be used to distinguish different FRB models and also discuss the practical possibility of using lensing observation in radio surveys to constrain FRB progenitors.

Li, ChunYu; Li, LiXin

2014-05-01

163

Viral disruption of olfactory progenitors is exacerbated in allergic mice.  

PubMed

Upper airway viral infection in patients with airway allergy often exacerbates olfactory dysfunction, but the mechanism for this exacerbation remains unclear. Here, we examined the effects of respiratory syncytial virus (RSV) infection, in the presence or absence of airway allergy, on olfactory receptor neurons (ORNs) and their progenitors in mice. Immunohistological analyses revealed that cockroach allergen (CRA)-induced airway allergy alone did not affect the number of OMP(+) mature ORNs and SOX2(+) ORN progenitors. Intranasal RSV line 19 infection in allergy-free mice resulted in a transient decrease in SOX2(+) ORN progenitors without affecting OMP(+) ORNs. In contrast, the RSV-induced decrease in SOX2(+) ORN progenitors was exacerbated and prolonged in allergic mice, which resulted in eventual loss of OMP(+) ORNs. In the allergic mice, reduction of RSV in the olfactory epithelium was delayed as compared with allergy-free mice. These results suggest that ORN progenitors were impaired by RSV infection and that airway allergy exacerbated damage to ORN progenitors by reducing viral clearance. PMID:24998164

Ueha, R; Mukherjee, S; Ueha, S; de Almeida Nagata, D E; Sakamoto, T; Kondo, K; Yamasoba, T; Lukacs, N W; Kunkel, S L

2014-09-01

164

Threshing efficiency as an incentive for rapid domestication of emmer wheat  

PubMed Central

Background and Aims The harvesting method of wild and cultivated cereals has long been recognized as an important factor in the emergence of domesticated non-shattering ear genotypes. This study aimed to quantify the effects of spike brittleness and threshability on threshing time and efficiency in emmer wheat, and to evaluate the implications of post-harvest processes on domestication of cereals in the Near East. Methods A diverse collection of tetraploid wheat genotypes, consisting of Triticum turgidum ssp. dicoccoides – the wild progenitor of domesticated wheat – traditional landraces, modern cultivars (T. turgidum ssp. durum) and 150 recombinant (wild × modern) inbred lines, was used in replicated controlled threshing experiments to quantify the effects of spike brittleness and threshability on threshing time and efficiency. Key Results The transition from a brittle hulled wild phenotype to non-brittle hulled phenotype (landraces) was associated with an approx. 30 % reduction in threshing time, whereas the transition from the latter to non-brittle free-threshing cultivars was associated with an approx. 85 % reduction in threshing time. Similar trends were obtained with groups of recombinant inbred lines showing extreme phenotypes of brittleness and threshability. Conclusions In tetraploid wheat, both non-brittle spike and free-threshing are labour-saving traits that increase the efficiency of post-harvest processing, which could have been an incentive for rapid domestication of the Near Eastern cereals, thus refuting the recently proposed hypothesis regarding extra labour associated with the domesticated phenotype (non-brittle spike) and its presumed role in extending the domestication episode time frame. PMID:23884398

Tzarfati, Raanan; Saranga, Yehoshua; Barak, Vered; Gopher, Avi; Korol, Abraham B.; Abbo, Shahal

2013-01-01

165

Human adult white matter progenitor cells are multipotent neuroprogenitors similar to adult hippocampal progenitors.  

PubMed

Adult neural progenitor cells (aNPC) are a potential autologous cell source for cell replacement in neurologic diseases or for cell-based gene therapy of neurometabolic diseases. Easy accessibility, long-term expandability, and detailed characterization of neural progenitor cell (NPC) properties are important requisites for their future translational/clinical applications. aNPC can be isolated from different regions of the adult human brain, including the accessible subcortical white matter (aNPCWM), but systematic studies comparing long-term expanded aNPCWM with aNPC from neurogenic brain regions are not available. Freshly isolated cells from subcortical white matter and hippocampus expressed oligodendrocyte progenitor cell markers such as A2B5, neuron-glial antigen 2 (NG2), and oligodendrocyte transcription factor 2 (OLIG2) in ?20% of cells but no neural stem cell (NSC) markers such as CD133 (Prominin1), Nestin, SOX2, or PAX6. The epidermal growth factor receptor protein was expressed in 18% of aNPCWM and 7% of hippocampal aNPC (aNPCHIP), but only a small fraction of cells, 1 of 694 cells from white matter and 1 of 1,331 hippocampal cells, was able to generate neurospheres. Studies comparing subcortical aNPCWM with their hippocampal counterparts showed that both NPC types expressed mainly markers of glial origin such as NG2, A2B5, and OLIG2, and the NSC/NPC marker Nestin, but no pericyte markers. Both NPC types were able to produce neurons, astrocytes, and oligodendrocytes in amounts comparable to fetal NSC. Whole transcriptome analyses confirmed the strong similarity of aNPCWM to aNPCHIP. Our data show that aNPCWM are multipotent NPC with long-term expandability similar to NPC from hippocampus, making them a more easily accessible source for possible autologous NPC-based treatment strategies. PMID:24558163

Lojewski, Xenia; Hermann, Andreas; Wegner, Florian; Araúzo-Bravo, Marcos J; Hallmeyer-Elgner, Susanne; Kirsch, Matthias; Schwarz, Johannes; Schöler, Hans R; Storch, Alexander

2014-04-01

166

Function and transcript analysis of gibberellin-biosynthetic enzymes in wheat.  

PubMed

The enzymes gibberellin (GA) 20-oxidase and 3-oxidase are major sites of regulation in GA biosynthesis. We have characterised one member of each of the gene families encoding these enzymes that are highly expressed in elongating stems and in developing and germinating grains of wheat and are therefore likely to have prominent developmental roles in these tissues. We mapped the three homoeologues of the GA 20-oxidase gene TaGA20ox1 to chromosomes 5BL, 5DL and 4AL. TaGA20ox1 is expressed mainly in the nodes and ears of the elongating stem, and also in developing and germinating embryos. Expression in the nodes, ears and germinating embryos is predominantly from the A and D genomes. Each homoeologous cDNA encodes a functional enzyme that catalyses the multi-step conversions of GA12-GA9, and GA53-GA20. Time course and enzyme kinetic studies indicate that the initial oxidation steps from GA12 and GA53 to the free alcohol forms of GA15 and GA44, respectively, occur rapidly but that subsequent steps occur more slowly. The intermediate GA19 has an especially low affinity for the enzyme, consistent with its accumulation in wheat tissues. The three homoeologous cDNAs for the 3-oxidase gene TaGA3ox2 encode functional enzymes, one of which was shown to possess low levels of 2beta-hydroxylase, 2,3-desaturase, 2,3-epoxidase and even 13-hydroxylase activities in addition to 3beta-hydroxylase activity. In contrast to TaGA20ox1, TaGA3ox2 is expressed in internodes, as well as nodes and the ear of the elongating stem. It is also highly expressed in developing and germinated embryos. PMID:16160850

Appleford, Nigel E J; Evans, Daniel J; Lenton, John R; Gaskin, Paul; Croker, Stephen J; Devos, Katrien M; Phillips, Andrew L; Hedden, Peter

2006-02-01

167

LMC Planetary Nebulae with Binary Progenitors  

NASA Astrophysics Data System (ADS)

Modern, high-resolution images of planetary nebulae (PNe) and pre- PNe, along with the most recent magneto-hydrodynamical models, have revealed a number of paradoxes in attempting to understand the mechanisms that govern the late stages of stellar evolution. New appeals to close binary interactions to shape axisymmetric PNe and govern their subsequent evolution must be reconciled with predictions of chemical yields of such systems, which show that common-envelope evolution will suppress the observed nitrogen super-enhancement in bipolar PNe. This program is a step along the path to determining the fraction of PNe with binary nuclei by leveraging two extensive, wide- area time domain surveys of the Large Magellanic Cloud (LMC): MACHO and SuperMACHO, from which we have already identified photometric variability in dozens of targets-a number in excess of all known Galactic PNe with binary central stars. Combined with a recent, 25 deg^2 discovery survey in H(alpha) for LMC PNe, which is complete at least 7 mag below the brightest in the PN luminosity function, we have a unique opportunity make a direct measurement of the binary fraction of PN progenitors, and thus to address one of the most pressing scientific questions in stellar evolution research.

Shaw, Richard A.; Hillwig, Todd; Rest, Armin

2008-08-01

168

TWEAK induces liver progenitor cell proliferation  

PubMed Central

Progenitor (“oval”) cell expansion accompanies many forms of liver injury, including alcohol toxicity and submassive parenchymal necrosis as well as experimental injury models featuring blocked hepatocyte replication. Oval cells can potentially become either hepatocytes or biliary epithelial cells and may be critical to liver regeneration, particularly when hepatocyte replication is impaired. The regulation of oval cell proliferation is incompletely understood. Herein we present evidence that a TNF family member called TWEAK (TNF-like weak inducer of apoptosis) stimulates oval cell proliferation in mouse liver through its receptor Fn14. TWEAK has no effect on mature hepatocytes and thus appears to be selective for oval cells. Transgenic mice overexpressing TWEAK in hepatocytes exhibit periportal oval cell hyperplasia. A similar phenotype was obtained in adult wild-type mice, but not Fn14-null mice, by administering TWEAK-expressing adenovirus. Oval cell expansion induced by 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) was significantly reduced in Fn14-null mice as well as in adult wild-type mice with a blocking anti-TWEAK mAb. Importantly, TWEAK stimulated the proliferation of an oval cell culture model. Finally, we show increased Fn14 expression in chronic hepatitis C and other human liver diseases relative to its expression in normal liver, which suggests a role for the TWEAK/Fn14 pathway in human liver injury. We conclude that TWEAK has a selective mitogenic effect for liver oval cells that distinguishes it from other previously described growth factors. PMID:16110324

Jakubowski, Aniela; Ambrose, Christine; Parr, Michael; Lincecum, John M.; Wang, Monica Z.; Zheng, Timothy S.; Browning, Beth; Michaelson, Jennifer S.; Baestcher, Manfred; Wang, Bruce; Bissell, D. Montgomery; Burkly, Linda C.

2005-01-01

169

Economic Effects of Standardizing Wheat Protein Reporting,  

National Technical Information Service (NTIS)

Wheat protein content has traditionally been reported on an 'as-is' moisture basis by the U.S. wheat trade. In an effort to provide inspection results which are easier to evaluate and compare, the Federal Grain Inspection Service (FGIS) began reporting pr...

L. A. Hoffman, J. L. Harwood, M. N. Leath

1988-01-01

170

Sequencing of Chloroplast Genomes from Wheat, Barley, Rye and Their Relatives Provides a Detailed Insight into the Evolution of the Triticeae Tribe  

PubMed Central

Using Roche/454 technology, we sequenced the chloroplast genomes of 12 Triticeae species, including bread wheat, barley and rye, as well as the diploid progenitors and relatives of bread wheat Triticum urartu, Aegilops speltoides and Ae. tauschii. Two wild tetraploid taxa, Ae. cylindrica and Ae. geniculata, were also included. Additionally, we incorporated wild Einkorn wheat Triticum boeoticum and its domesticated form T. monococcum and two Hordeum spontaneum (wild barley) genotypes. Chloroplast genomes were used for overall sequence comparison, phylogenetic analysis and dating of divergence times. We estimate that barley diverged from rye and wheat approximately 8–9 million years ago (MYA). The genome donors of hexaploid wheat diverged between 2.1–2.9 MYA, while rye diverged from Triticum aestivum approximately 3–4 MYA, more recently than previously estimated. Interestingly, the A genome taxa T. boeoticum and T. urartu were estimated to have diverged approximately 570,000 years ago. As these two have a reproductive barrier, the divergence time estimate also provides an upper limit for the time required for the formation of a species boundary between the two. Furthermore, we conclusively show that the chloroplast genome of hexaploid wheat was contributed by the B genome donor and that this unknown species diverged from Ae. speltoides about 980,000 years ago. Additionally, sequence alignments identified a translocation of a chloroplast segment to the nuclear genome which is specific to the rye/wheat lineage. We propose the presented phylogeny and divergence time estimates as a reference framework for future studies on Triticeae. PMID:24614886

Middleton, Christopher P.; Senerchia, Natacha; Stein, Nils; Akhunov, Eduard D.; Keller, Beat

2014-01-01

171

Sequencing of chloroplast genomes from wheat, barley, rye and their relatives provides a detailed insight into the evolution of the Triticeae tribe.  

PubMed

Using Roche/454 technology, we sequenced the chloroplast genomes of 12 Triticeae species, including bread wheat, barley and rye, as well as the diploid progenitors and relatives of bread wheat Triticum urartu, Aegilops speltoides and Ae. tauschii. Two wild tetraploid taxa, Ae. cylindrica and Ae. geniculata, were also included. Additionally, we incorporated wild Einkorn wheat Triticum boeoticum and its domesticated form T. monococcum and two Hordeum spontaneum (wild barley) genotypes. Chloroplast genomes were used for overall sequence comparison, phylogenetic analysis and dating of divergence times. We estimate that barley diverged from rye and wheat approximately 8-9 million years ago (MYA). The genome donors of hexaploid wheat diverged between 2.1-2.9 MYA, while rye diverged from Triticum aestivum approximately 3-4 MYA, more recently than previously estimated. Interestingly, the A genome taxa T. boeoticum and T. urartu were estimated to have diverged approximately 570,000 years ago. As these two have a reproductive barrier, the divergence time estimate also provides an upper limit for the time required for the formation of a species boundary between the two. Furthermore, we conclusively show that the chloroplast genome of hexaploid wheat was contributed by the B genome donor and that this unknown species diverged from Ae. speltoides about 980,000 years ago. Additionally, sequence alignments identified a translocation of a chloroplast segment to the nuclear genome which is specific to the rye/wheat lineage. We propose the presented phylogeny and divergence time estimates as a reference framework for future studies on Triticeae. PMID:24614886

Middleton, Christopher P; Senerchia, Natacha; Stein, Nils; Akhunov, Eduard D; Keller, Beat; Wicker, Thomas; Kilian, Benjamin

2014-01-01

172

The Progenitors of Dwarf Spheroidal Galaxies  

E-print Network

Dwarf spheroidal (dSph) galaxies present an evolutionary puzzle that we explore in 40 early- and late-type dwarfs in the Local Group and nearby field. Although dSphs formed stars over extended periods, today all but one are free of detectable interstellar matter (ISM), even in the Fornax dSph, where stars still formed 100 Myr ago. Combining metallicities for red giants with HI data from the literature, we show that the well-known offset in luminosity-metallicity (L-Z) relations for dSphs and dwarf irregular (dIrr) galaxies exists also when comparing only their old stellar populations: dSphs have higher mean stellar metallicities for a fixed luminosity. Evidently younger dSphs experienced more efficient enrichment than young dIrrs. Dwarf galaxies, whose locus in the L-Z diagram is consistent with that of dSphs even for baryonic luminosities, are the ``transition-type dwarfs'' Phoenix, DDO210, LGS3, Antlia, and KKR25. They have mixed dIrr/dSph morphologies, low stellar masses, low angular momentum, and HI contents of less than a few 10^6 solar masses. Unlike dIrrs, many transition-type dwarfs would closely resemble dSphs if their gas were removed; they are likely dSph progenitors. As gas removal is key, we consider the empirical evidence for various gas removal processes. We suggest that internal gas removal mechanisms are inadequate and favor ram pressure stripping to make dSphs. A combination of initial conditions and environment seems to support the formation of dSphs, which appear to form from small galaxies with active early star formation, whose evolution halts due to externally induced gas loss. Transition-type dwarfs then are dSphs that kept their ISM, and therefore should replace dSphs in isolated locations where stripping is ineffective. (Abridged)

Eva K. Grebel; John S. Gallagher; Daniel Harbeck

2003-01-02

173

Endothelial progenitor cells in acute ischemic stroke  

PubMed Central

Objectives The levels of circulating endothelial progenitor cells (EPCs) in ischemic stroke have not been studied extensively and reported results are inconsistent. We aimed to investigate the time course, the prognostic relevance, and the variables associated with EPC counts in patients with ischemic stroke at different time points. Material and methods We studied prospectively 146 consecutive patients with ischemic stroke within the first 48 h from the onset of symptoms (baseline). We evaluated demographic data, classical vascular risk factors, treatment with thrombolysis and statins, stroke etiology, National Institute of Health and Stroke Scale score and outcome (favorable when Rankin scale score 0–2). Blood samples were collected at baseline, at day 7 after stroke (n = 121) and at 3 months (n = 92). The EPC were measured by flow cytometry. Results We included 146 patients with a mean age of 70.8 ± 12.2 years. The circulating EPC levels were higher on day 7 than at baseline or at 3 months (P = 0.045). Pretreatment with statins (odds ratio [OR] 3.11, P = 0.008) and stroke etiology (P = 0.032) were predictive of EPC counts in the baseline sample. EPC counts were not associated with stroke severity or functional outcome in all the patients. However, using multivariate analyses, a better functional outcome was found in patients with higher EPC counts in large-artery atherosclerosis and small-vessel disease etiologic subtypes. Conclusions After acute ischemic stroke, circulating EPC counts peaked at day 7. Pretreatment with statins increased the levels of EPC. In patients with large-artery atherosclerosis and small-vessel disease subtypes, higher counts were related to better outcome at 3 months. PMID:24363968

Martí-Fàbregas, Joan; Crespo, Javier; Delgado-Mederos, Raquel; Martínez-Ramírez, Sergi; Peña, Esther; Marín, Rebeca; Dinia, Lavinia; Jiménez-Xarrié, Elena; Fernández-Arcos, Ana; Pérez-Pérez, Jesús; Querol, Luis; Suárez-Calvet, Marc; Badimon, Lina

2013-01-01

174

Endothelial progenitor cells in diabetic retinopathy.  

PubMed

Diabetic retinopathy (DR) is a leading cause of visual impairment worldwide. Patients with DR may irreversibly lose sight as a result of the development of diabetic macular edema (DME) and/or proliferative diabetic retinopathy (PDR); retinal blood vessel dysfunction and degeneration plays an essential role in their pathogenesis. Although new treatments have been recently introduced for DME, including intravitreal vascular endothelial growth factor inhibitors (anti-VEGFs) and steroids, a high proportion of patients (~40-50%) do not respond to these therapies. Furthermore, for people with PDR, laser photocoagulation remains a mainstay therapy despite this being an inherently destructive procedure. Endothelial progenitor cells (EPCs) are a low-frequency population of circulating cells known to be recruited to sites of vessel damage and tissue ischemia where they promote vascular healing and re-perfusion. A growing body of evidence suggests that the number and function of EPCs are altered in patients with varying degrees of diabetes duration, metabolic control, and in the presence or absence of DR. Although there are no clear-cut outcomes from these clinical studies, there is mounting evidence that some EPC sub-types may be involved in the pathogenesis of DR and may also serve as biomarkers for disease progression and stratification. Moreover, some EPC sub-types have considerable potential as therapeutic modalities for DME and PDR in the context of cell therapy. This study presents basic clinical concepts of DR and combines this with a general insight on EPCs and their relation to future directions in understanding and treating this important diabetic complication. PMID:24782825

Lois, Noemi; McCarter, Rachel V; O'Neill, Christina; Medina, Reinhold J; Stitt, Alan W

2014-01-01

175

Influence of aFusarium culmorum inoculation of wheat onin sacco dry matter degradation of wheat straw and wheat chaff.  

PubMed

The aim of this study was to investigate the effect of aFusarium culmorum inoculation of wheat on thein sacco dry matter degradation (DG) of wheat straw and wheat chaff in dairy cows. The ruminal disappearance of dry matter was measured with thein situ nylon bag technique. Samples of wheat straw and wheat chaff from non-inoculated andFusarium-inoculated wheat were used to examine the ruminal dry matter degradability. Samples were subjected to ruminal incubation in two dairy cous fitted with a permanent rumen fistula and incubated for 4, 8, 16, 24, 48, 72, 96 and 120 h. To describe the degradation kinetics, the equation by Ørskov and McDonald (1979) was used. DG rates obtained for contaminates straw and chaff were higher compared to the corresponding rates of the non-contaminated samples, which is assumed to be due to the activity of fungal enzymes. It can be concluded that an infection of wheat withF. culmorum may have an influence on the dry matter degradation of straw and chaff. PMID:23605214

Brinkmeyer, U; Dänicke, S; Lehmann, M; Lebzien, P; Valenta, H; Flachowsky, G

2005-03-01

176

SUPERNOVA 2008bk AND ITS RED SUPERGIANT PROGENITOR  

SciTech Connect

We have obtained limited photometric and spectroscopic data for supernova (SN) 2008bk in NGC 7793, primarily at {approx}> 150 days after explosion. We find that it is a Type II-Plateau (II-P) SN that most closely resembles the low-luminosity SN 1999br in NGC 4900. Given the overall similarity between the observed light curves and colors of SNe 2008bk and 1999br, we infer that the total visual extinction to SN 2008bk (A{sub V} = 0.065 mag) must be almost entirely due to the Galactic foreground, similar to what has been assumed for SN 1999br. We confirm the identification of the putative red supergiant (RSG) progenitor star of the SN in high-quality g'r'i' images we had obtained in 2007 at the Gemini-South 8 m telescope. Little ambiguity exists in this progenitor identification, qualifying it as the best example to date, next to the identification of the star Sk -69 Degree-Sign 202 as the progenitor of SN 1987A. From a combination of photometry of the Gemini images with that of archival, pre-SN, Very Large Telescope JHK{sub s} images, we derive an accurate observed spectral energy distribution (SED) for the progenitor. We find from nebular strong-intensity emission-line indices for several H II regions near the SN that the metallicity in the environment is likely subsolar (Z Almost-Equal-To 0.6 Z{sub Sun }). The observed SED of the star agrees quite well with synthetic SEDs obtained from model RSG atmospheres with effective temperature T{sub eff} = 3600 {+-} 50 K. We find, therefore, that the star had a bolometric luminosity with respect to the Sun of log (L{sub bol}/L{sub Sun} ) = 4.57 {+-} 0.06 and radius R{sub *} = 496 {+-} 34 R{sub Sun} at {approx}6 months prior to explosion. Comparing the progenitor's properties with theoretical massive-star evolutionary models, we conclude that the RSG progenitor had an initial mass in the range of 8-8.5 M{sub Sun }. This mass is consistent with, albeit at the low end of, the inferred range of initial masses for SN II-P progenitors. It is also consistent with the estimated upper limit on the initial mass of the progenitor of SN 1999br, and it agrees with the low initial masses found for the RSG progenitors of other low-luminosity SNe II-P.

Van Dyk, Schuyler D.; Elias-Rosa, Nancy [Spitzer Science Center/Caltech, Mailcode 220-6, Pasadena, CA 91125 (United States); Davidge, Tim J., E-mail: vandyk@ipac.caltech.edu, E-mail: tim.davidge@nrc.ca [Herzberg Institute of Astrophysics, National Research Council of Canada, Victoria, B.C., V9E 2E7 (Canada); and others

2012-01-15

177

Genes encoding 4-Cys antimicrobial peptides in wheat Triticum kiharae Dorof. et Migush.: multimodular structural organization, instraspecific variability, distribution and role in defence.  

PubMed

A novel family of antifungal peptides was discovered in the wheat Triticum kiharae Dorof. et Migusch. Two members of the family, designated Tk-AMP-X1 and Tk-AMP-X2, were completely sequenced and shown to belong to the ?-hairpinin structural family of plant peptides with a characteristic C1XXXC2-X(n)-C3XXXC4 motif. The peptides inhibit the spore germination of several fungal pathogens in vitro. cDNA and gene cloning disclosed unique structure of genes encoding Tk-AMP-X peptides. They code for precursor proteins of unusual multimodular structure, consisting of a signal peptide, several ?-hairpinin (4-Cys) peptide domains with a characteristic cysteine pattern separated by linkers and a C-terminal prodomain. Three types of precursor proteins, with five, six or seven 4-Cys peptide modules, were found in wheat. Among the predicted family members, several peptides previously isolated from T. kiharae seeds were identified. Genes encoding Tk-AMP-X precursors have no introns in the protein-coding regions and are upregulated by fungal pathogens and abiotic stress, providing conclusive evidence for their role in stress response. A combined PCR-based and bioinformatics approach was used to search for related genes in the plant kingdom. Homologous genes differing in the number of peptide modules were discovered in phylogenetically-related Triticum and Aegilops species, including polyploid wheat genome donors. Association of the Tk-AMP-X genes with A, B/G or D genomes of hexaploid wheat was demonstrated. Furthermore, Tk-AMP-X-related sequences were shown to be widespread in the Poaceae family among economically important crops, such as barley, rice and maize. PMID:23702306

Utkina, Lyubov L; Andreev, Yaroslav A; Rogozhin, Eugene A; Korostyleva, Tatyana V; Slavokhotova, Anna A; Oparin, Peter B; Vassilevski, Alexander A; Grishin, Eugene V; Egorov, Tsezi A; Odintsova, Tatyana I

2013-08-01

178

Resistance to soil-borne wheat mosaic virus (SBWMV) in durum wheat. H Lapierre 1, HH Lapierre H  

E-print Network

in the 2 resis- tant durum wheat cvs 17 d after seed germination at 15°C in infected soil. At the same dateResistance to soil-borne wheat mosaic virus (SBWMV) in durum wheat. H Lapierre 1, HH Lapierre H cedex; 2 Coopérative de la Franciade, F-41021 Blois, France) Two durum wheat cvs (Seti and Prodigal

Paris-Sud XI, Université de

179

NFIX regulates neural progenitor cell differentiation during hippocampal morphogenesis.  

PubMed

Neural progenitor cells have the ability to give rise to neurons and glia in the embryonic, postnatal and adult brain. During development, the program regulating whether these cells divide and self-renew or exit the cell cycle and differentiate is tightly controlled, and imbalances to the normal trajectory of this process can lead to severe functional consequences. However, our understanding of the molecular regulation of these fundamental events remains limited. Moreover, processes underpinning development of the postnatal neurogenic niches within the cortex remain poorly defined. Here, we demonstrate that Nuclear factor one X (NFIX) is expressed by neural progenitor cells within the embryonic hippocampus, and that progenitor cell differentiation is delayed within Nfix(-/-) mice. Moreover, we reveal that the morphology of the dentate gyrus in postnatal Nfix(-/-) mice is abnormal, with fewer subgranular zone neural progenitor cells being generated in the absence of this transcription factor. Mechanistically, we demonstrate that the progenitor cell maintenance factor Sry-related HMG box 9 (SOX9) is upregulated in the hippocampus of Nfix(-/-) mice and demonstrate that NFIX can repress Sox9 promoter-driven transcription. Collectively, our findings demonstrate that NFIX plays a central role in hippocampal morphogenesis, regulating the formation of neuronal and glial populations within this structure. PMID:23042739

Heng, Yee Hsieh Evelyn; McLeay, Robert C; Harvey, Tracey J; Smith, Aaron G; Barry, Guy; Cato, Kathleen; Plachez, Céline; Little, Erica; Mason, Sharon; Dixon, Chantelle; Gronostajski, Richard M; Bailey, Timothy L; Richards, Linda J; Piper, Michael

2014-01-01

180

The Progenitor Mass of the Magnetar SGR1900+14  

NASA Astrophysics Data System (ADS)

Magnetars are young neutron stars with extreme magnetic fields (B gsim 1014-1015 G). How these fields relate to the properties of their progenitor stars is not yet clearly established. However, from the few objects associated with young clusters it has been possible to estimate the initial masses of the progenitors, with results indicating that a very massive progenitor star (M prog> 40 M _{?}) is required to produce a magnetar. Here, we present adaptive-optics assisted Keck/NIRC2 imaging and Keck/NIRSPEC spectroscopy of the cluster associated with the magnetar SGR 1900+14, and report that the initial progenitor star mass of the magnetar was a factor of 2 lower than this limit, M prog = 17 ± 2 M_{?}. Our result presents a strong challenge to the concept that magnetars can only result from very massive progenitors. Instead, we favor a mechanism which is dependent on more than just initial stellar mass for the production of these extreme magnetic fields, such as the "fossil-field" model or a process involving close binary evolution.

Davies, Ben; Figer, Don F.; Kudritzki, Rolf-Peter; Trombley, Christine; Kouveliotou, Chryssa; Wachter, Stefanie

2009-12-01

181

Observational Clues to the Progenitors of Type Ia Supernovae  

NASA Astrophysics Data System (ADS)

Type Ia supernovae (SNe Ia) are important distance indicators, element factories, cosmic-ray accelerators, kinetic-energy sources in galaxy evolution, and end points of stellar binary evolution. It has long been clear that a SN Ia must be the runaway thermonuclear explosion of a degenerate carbon-oxygen stellar core, most likely a white dwarf (WD). However, the specific progenitor systems of SNe Ia, and the processes that lead to their ignition, have not been identified. Two broad classes of progenitor binary systems have long been considered: single-degenerate (SD), in which a WD gains mass from a nondegenerate star; and double-degenerate (DD), involving the merger of two WDs. New theoretical work has enriched these possibilities with some interesting updates and variants. We review the significant recent observational progress in addressing the progenitor problem. We consider clues that have emerged from the observed properties of the various proposed progenitor populations, from studies of SN Ia sites—pre- and postexplosion—from analysis of the explosions themselves and from the measurement of event rates. The recent nearby and well-studied event, SN 2011fe, has been particularly revealing. The observational results are not yet conclusive and sometimes prone to competing theoretical interpretations. Nevertheless, it appears that DD progenitors, long considered the underdog option, could be behind some, if not all, SNe Ia. We point to some directions that may lead to future progress.

Maoz, Dan; Mannucci, Filippo; Nelemans, Gijs

2014-08-01

182

THE TYPE IIb SUPERNOVA 2011dh FROM A SUPERGIANT PROGENITOR  

SciTech Connect

A set of hydrodynamical models based on stellar evolutionary progenitors is used to study the nature of SN 2011dh. Our modeling suggests that a large progenitor star-with R {approx} 200 R{sub Sun }-is needed to reproduce the early light curve (LC) of SN 2011dh. This is consistent with the suggestion that the yellow super-giant star detected at the location of the supernova (SN) in deep pre-explosion images is the progenitor star. From the main peak of the bolometric LC and expansion velocities, we constrain the mass of the ejecta to be Almost-Equal-To 2 M{sub Sun }, the explosion energy to be E = (6-10) Multiplication-Sign 10{sup 50} erg, and the {sup 56}Ni mass to be approximately 0.06 M{sub Sun }. The progenitor star was composed of a helium core of 3-4 M{sub Sun} and a thin hydrogen-rich envelope of Almost-Equal-To 0.1M{sub Sun} with a main-sequence mass estimated to be in the range of 12-15 M{sub Sun }. Our models rule out progenitors with helium-core masses larger than 8 M{sub Sun }, which correspond to M{sub ZAMS} {approx}> 25M{sub Sun }. This suggests that a single star evolutionary scenario for SN 2011dh is unlikely.

Bersten, Melina C.; Nomoto, Ken'ichi; Folatelli, Gaston; Maeda, Keiichi [Kavli Institute for the Physics and Mathematics of the Universe, Todai Institutes for Advanced Study, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Benvenuto, Omar G. [Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, Paseo del Bosque S/N, B1900FWA La Plata (Argentina); Ergon, Mattias; Sollerman, Jesper [The Oskar Klein Centre, Department of Astronomy, AlbaNova, SE-106 91 Stockholm (Sweden); Benetti, Stefano; Ochner, Paolo; Tomasella, Lina [INAF-Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, I-35122 Padova (Italy); Botticella, Maria Teresa [INAF-Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, I-80131 Napoli (Italy); Fraser, Morgan; Kotak, Rubina, E-mail: melina.bersten@ipmu.jp [Astrophysics Research Centre, School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN (United Kingdom)

2012-09-20

183

Transcriptome analysis of neural progenitor cells by a genetic dual reporter strategy.  

PubMed

Global analysis of stem/progenitor cells promises new insight into mechanisms that govern self-renewal and cellular potential, an unresolved question of stem/progenitor cell biology. Despite rapid advance of genome-wide profiling methods, the difficulty in cell purification remains a major challenge for global analysis of somatic stem/progenitor cells. Genetic tagging with a reporter provides a powerful tool for identification and isolation of a specific mature cell type; however, for stem/progenitor cells, reporter retention by progeny may be a concern for impurity. Here, we describe a genetic system combining a progenitor cell specific label with a second tag for marking differentiation. We present evidence that differential labeling of neural progenitor cells and their progeny enables prospective purification of these two cell types, whereas isolation based on a single marker compromises the purity of the intended progenitor population. Comparative expression profiling between the purified progenitors and progeny documents a neural progenitor cell transcriptome and uncovers an important role of Tyro3/Axl/Mer receptor tyrosine kinases in the maintenance of neural progenitor cells. This study establishes a general strategy for isolation of somatic stem/progenitor cells and provides a transcriptome database of neural progenitor cells useful for identification of causal factors of neural progenitor cell state, global dissection of epigenetic control of cellular potential, as well as for developing biomarkers or targets of brain cancer stem/initiating cells for therapeutic interventions. PMID:21805534

Wang, Jun; Zhang, Heying; Young, Amanda G; Qiu, Runxiang; Argalian, Siranush; Li, Xuejun; Wu, Xiwei; Lemke, Greg; Lu, Qiang

2011-10-01

184

Ultrafiltration to fractionate wheat polypeptides.  

PubMed

An ultrafiltration process allowing the fractionation of two kinds of polypeptides issued from limited chymotryptic hydrolysis of wheat gliadins was applied to wheat gluten hydrolysates. Hydrophilic and poorly charged polypeptides were well transmitted through an inorganic ZrO2-based membrane at acidic pH, whereas hydrophobic and positively charged polypeptides were highly retained. By combining reversed-phase and cation-exchange chromatography (CEC), it was proved that the fractionation of the polypeptides was based on electrostatic repulsion of the charged polypeptides by the positively charged membrane. After a continuous diafiltration process, retentates containing 75 to 88% of hydrophobic polypeptide and permeates containing 84 to 90% of hydrophilic polypeptides were recovered, depending on the size of membrane used. Even if the ultrafiltration fractions were less purified than fractions issued from CEC, it was shown that they exhibited very different foaming properties: permeate did not produce nor stabilize foams, whereas retentate was more efficient than the whole hydrolysates and BSA. PMID:11302444

Berot, S; Popineau, Y; Compoint, J P; Blassel, C; Chaufer, B

2001-03-25

185

Wheat production in controlled environments  

NASA Technical Reports Server (NTRS)

Conditions are optimized for maximum yield and quality of wheat to be used in a controlled environment life support system (CELSS) in a Lunar or Martian base or a spacecraft. With yields of 23 to 57 g/sq m/d of edible biomass, a minimum size for a CELSS would be between 12 and 30 sq m per person, utilizing about 600 W/sq m of electrical energy for artificial light. Temperature, irradiance, photoperiod, carbon dioxide levels, humidity, and wind velocity are controlled in growth chambers. Nutrient solutions (adjusted for wheat) are supplied to the roots via a recirculating system that controls pH by adding HNO3 and controlling the NO3/NH4 ratio in solution. A rock-wool plant support allows direct seeding and densities up to 10,000 plants sq m. Densities up to 2000 plants/sq m appear to increase seed yield. Biomass production increases almost linearily with increasing irradiance from 400 to 1700 micromol/sq m/s of photosynthetic photon flux, but the efficiency of light utilization decreases over this range. Photoperiod and temperature both have a profound influence on floral initiation, spikelet formation, stem elongation, and fertilization.

Salisbury, Frank B.; Bugbee, Bruce; Bubenheim, David

1987-01-01

186

Micromilling enhances iron bioaccessibility from wholegrain wheat.  

PubMed

Cereals constitute important sources of iron in human diet; however, much of the iron in wheat is lost during processing for the production of white flour. This study employed novel food processing techniques to increase the bioaccessibility of naturally occurring iron in wheat. Iron was localized in wheat by Perl's Prussian blue staining. Soluble iron from digested wheat flour was measured by a ferrozine spectrophotometric assay. Iron bioaccessibility was determined using an in vitro simulated peptic-pancreatic digestion, followed by measurement of ferritin (a surrogate marker for iron absorption) in Caco-2 cells. Light microscopy revealed that iron in wheat was encapsulated in cells of the aleurone layer and remained intact after in vivo digestion and passage through the gastrointestinal tract. The solubility of iron in wholegrain wheat and in purified wheat aleurone increased significantly after enzymatic digestion with Driselase, and following mechanical disruption using micromilling. Furthermore, following in vitro simulated peptic-pancreatic digestion, iron bioaccessibility, measured as ferritin formation in Caco-2 cells, from micromilled aleurone flour was significantly higher (52%) than from whole aleurone flour. Taken together our data show that disruption of aleurone cell walls could increase iron bioaccessibility. Micromilled aleurone could provide an alternative strategy for iron fortification of cereal products. PMID:25380143

Latunde-Dada, G O; Li, X; Parodi, A; Edwards, C H; Ellis, P R; Sharp, P A

2014-11-19

187

Separability study of wheat and small grains  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. Barley showed significant separability from spring wheat, both multitemporally and on a single date chosen near the turning time for barley. Oats showed occasional multitemporal separability from barley and spring wheat; however, the cause of this separability was not well understood. Oats showed no significant separability from spring wheat on any single date during the growing season. By pooling data from segments having an acquisition near the turning time for barley, a fixed unitemporal projection for aiding in the labeling of barley versus spring wheat and oats was constructed. This projection has about the same separability of barley from spring wheat and oats as the unitemporal greeness versus brightness plot. The new fixed projection has the advantage that barley occurs consistently in the same general location on the plot with respect to spring wheat and oats. Attempts to construct a fixed multitemporal or a segment-dependent multitemporal projection for aiding in the labeling of spring wheat versus other small grains were unsuccessful due to segment availability and the fact that each segment has a unique acquisition history.

Lennington, R. K.; Marquina, N. E. (principal investigators)

1978-01-01

188

Hematopoietic Stem and Progenitor Cells in Inflammation and Allergy  

PubMed Central

Hematopoietic stem and progenitor cells contribute to allergic inflammation. Pro-inflammatory cytokines that are generated following allergen challenge can impact the differentiation of hematopoietic progenitor cells leading to increased production of effector cells such as eosinophils and basophils, which are key cells involved in the pathogenesis of allergic airway inflammation. Homing of stem cells to the lungs is associated with inflammatory and remodeling changes in asthmatics. Factors that modulate the differentiation and increased migration of stem cells to the site of inflammation in asthma remain to be defined. Stem cells can mature at the site of inflammation in response to inflammatory mediators and other components in the milieu. While the available data suggest that hematopoietic cells traffic to target tissues, the molecular factors underlying in situ differentiation have yet to be specified. Here, we critically evaluate the potential role of hematopoietic progenitors in contributing to the increased immune cell infiltrate in allergic asthma and the factors that drive their differentiation. PMID:24363657

Fischer, Kimberly D.; Agrawal, Devendra K.

2013-01-01

189

Transcriptome Analysis Identifies Regulators of Hematopoietic Stem and Progenitor Cells  

PubMed Central

Summary Hematopoietic stem cells (HSCs) maintain blood homeostasis and are the functional units of bone marrow transplantation. To improve the molecular understanding of HSCs and their proximal progenitors, we performed transcriptome analysis within the context of the ImmGen Consortium data set. Gene sets that define steady-state and mobilized HSCs, as well as hematopoietic stem and progenitor cells (HSPCs), were determined. Genes involved in transcriptional regulation, including a group of putative transcriptional repressors, were identified in multipotent progenitors and HSCs. Proximal promoter analyses combined with ImmGen module analysis identified candidate regulators of HSCs. Enforced expression of one predicted regulator, Hlf, in diverse HSPC subsets led to extensive self-renewal activity ex vivo. These analyses reveal unique insights into the mechanisms that control the core properties of HSPCs. PMID:24319662

Gazit, Roi; Garrison, Brian S.; Rao, Tata Nageswara; Shay, Tal; Costello, James; Ericson, Jeff; Kim, Francis; Collins, James J.; Regev, Aviv; Wagers, Amy J.; Rossi, Derrick J.

2013-01-01

190

Wharton's jelly mesenchymal stem cells differentiate into retinal progenitor cells  

PubMed Central

Human Wharton's jelly mesenchymal stem cells were isolated from fetal umbilical cord. Cells were cultured in serum-free neural stem cell-conditioned medium or neural stem cell-conditioned medium supplemented with Dkk-1, a Wnt/? catenin pathway antagonist, and LeftyA, a Nodal signaling pathway antagonist to induce differentiation into retinal progenitor cells. Inverted microscopy showed that after induction, the spindle-shaped or fibroblast-like Wharton's jelly mesenchymal stem cells changed into bulbous cells with numerous processes. Immunofluorescent cytochemical ing and reverse-transcription PCR showed positive expression of retinal progenitor cell markers, Pax6 and Rx, as well as weakly down-regulated nestin expression. These results demonstrate that Wharton's jelly mesenchymal stem cells are capable of differentiating into retinal progenitor cells in vitro.

Hu, Ying; Liang, Jun; Cui, Hongping; Wang, Xinmei; Rong, Hua; Shao, Bin; Cui, Hao

2013-01-01

191

Obstructive sleep apnea and endothelial progenitor cells  

PubMed Central

Background Obstructive sleep apnea (OSA) occurs in 4% of middle-aged men and 2% of middle-aged women in the general population, and the prevalence is even higher in specific patient groups. OSA is an independent risk factor for a variety of cardiovascular diseases. Endothelial injury could be the pivotal determinant in the development of cardiovascular pathology in OSA. Endothelial damage ultimately represents a dynamic balance between the magnitude of injury and the capacity for repair. Bone marrow–derived endothelial progenitor cells (EPCs) within adult peripheral blood present a possible means of vascular maintenance that could home to sites of injury and restore endothelial integrity and normal function. Methods We summarized pathogenetic mechanisms of OSA and searched for available studies on numbers and functions of EPCs in patients with OSA to explore the potential links between the numbers and functions of EPCs and OSA. In particular, we tried to elucidate the molecular mechanisms of the effects of OSA on EPCs. Conclusion Intermittent hypoxia cycles and sleep fragmentation are major pathophysiologic characters of OSA. Intermittent hypoxia acts as a trigger of oxidative stress, systemic inflammation, and sympathetic activation. Sleep fragmentation is associated with a burst of sympathetic activation and systemic inflammation. In most studies, a reduction in circulating EPCs has emerged. The possible mechanisms underlying the decrease in the number or function of EPCs include prolonged inflammation response, oxidative stress, increased sympathetic activation, physiological adaptive responses of tissue to hypoxia, reduced EPC mobilization, EPC apoptosis, and functional impairment in untreated OSA. Continuous positive airway pressure (CPAP) therapy for OSA affects the mobilization, apoptosis, and function of EPCs through preventing intermittent hypoxia episodes, improving sleep quality, and reducing systemic inflammation, oxidative stress levels, and sympathetic overactivation. To improve CPAP adherence, the medical staff should pay attention to making the titration trial a comfortable first CPAP experience for the patients; for example, using the most appropriate ventilators or proper humidification. It is also important to give the patients education and support about CPAP use in the follow-up, especially in the early stage of the treatment. PMID:24204127

Wang, Qing; Wu, Qi; Feng, Jing; Sun, Xin

2013-01-01

192

Rates and progenitors of type Ia supernovae  

SciTech Connect

The remarkable uniformity of Type Ia supernovae has allowed astronomers to use them as distance indicators to measure the properties and expansion history of the Universe. However, Type Ia supernovae exhibit intrinsic variation in both their spectra and observed brightness. The brightness variations have been approximately corrected by various methods, but there remain intrinsic variations that limit the statistical power of current and future observations of distant supernovae for cosmological purposes. There may be systematic effects in this residual variation that evolve with redshift and thus limit the cosmological power of SN Ia luminosity-distance experiments. To reduce these systematic uncertainties, we need a deeper understanding of the observed variations in Type Ia supernovae. Toward this end, the Nearby Supernova Factory has been designed to discover hundreds of Type Ia supernovae in a systematic and automated fashion and study them in detail. This project will observe these supernovae spectrophotometrically to provide the homogeneous high-quality data set necessary to improve the understanding and calibration of these vital cosmological yardsticks. From 1998 to 2003, in collaboration with the Near-Earth Asteroid Tracking group at the Jet Propulsion Laboratory, a systematic and automated searching program was conceived and executed using the computing facilities at Lawrence Berkeley National Laboratory and the National Energy Research Supercomputing Center. An automated search had never been attempted on this scale. A number of planned future large supernovae projects are predicated on the ability to find supernovae quickly, reliably, and efficiently in large datasets. A prototype run of the SNfactory search pipeline conducted from 2002 to 2003 discovered 83 SNe at a final rate of 12 SNe/month. A large, homogeneous search of this scale offers an excellent opportunity to measure the rate of Type Ia supernovae. This thesis presents a new method for analyzing the true sensitivity of a multi-epoch supernova search and finds a Type Ia supernova rate from z {approx} 0.01-0.1 of r{sub V} = 4.26{sub -1.93 -0.10}{sup +1.39 +0.10} h{sup 3} x 10{sup -4} SNe Ia/yr/Mpc{sup 3} from a preliminary analysis of a subsample of the SNfactory prototype search. Several unusual supernovae were found in the course of the SNfactory prototype search. One in particular, SN 2002ic, was the first SN Ia to exhibit convincing evidence for a circumstellar medium and offers valuable insight into the progenitors of Type Ia supernovae.

Wood-Vasey, William Michael

2004-08-16

193

Hematopoietic stem cell and progenitor cell mechanisms in myelodysplastic syndromes.  

PubMed

Myelodysplastic syndromes (MDS) are a group of disorders characterized by variable cytopenias and ineffective hematopoiesis. Hematopoietic stem cells (HSCs) and myeloid progenitors in MDS have not been extensively characterized. We transplanted purified human HSCs from MDS samples into immunodeficient mice and show that HSCs are the disease-initiating cells in MDS. We identify a recurrent loss of granulocyte-macrophage progenitors (GMPs) in the bone marrow of low risk MDS patients that can distinguish low risk MDS from clinical mimics, thus providing a simple diagnostic tool. The loss of GMPs is likely due to increased apoptosis and increased phagocytosis, the latter due to the up-regulation of cell surface calreticulin, a prophagocytic marker. Blocking calreticulin on low risk MDS myeloid progenitors rescues them from phagocytosis in vitro. However, in the high-risk refractory anemia with excess blasts (RAEB) stages of MDS, the GMP population is increased in frequency compared with normal, and myeloid progenitors evade phagocytosis due to up-regulation of CD47, an antiphagocytic marker. Blocking CD47 leads to the selective phagocytosis of this population. We propose that MDS HSCs compete with normal HSCs in the patients by increasing their frequency at the expense of normal hematopoiesis, that the loss of MDS myeloid progenitors by programmed cell death and programmed cell removal are, in part, responsible for the cytopenias, and that up-regulation of the "don't eat me" signal CD47 on MDS myeloid progenitors is an important transition step leading from low risk MDS to high risk MDS and, possibly, to acute myeloid leukemia. PMID:23388639

Pang, Wendy W; Pluvinage, John V; Price, Elizabeth A; Sridhar, Kunju; Arber, Daniel A; Greenberg, Peter L; Schrier, Stanley L; Park, Christopher Y; Weissman, Irving L

2013-02-19

194

Durum wheat and allelopathy: toward wheat breeding for natural weed management  

PubMed Central

Wheat-derived foodstuffs represent about one-fifth of the calories consumed by humans worldwide. Bread wheat (Triticum aestivum L.) is one of the most important crops throughout the world, and it has been extensively studied for its allelopathic potential. In contrast, for allelopathy in durum wheat (Triticum turgidum ssp. durum), our knowledge is partial and fragmentary. Through highlighting recent advances in using allelopathy as a crop-breeding tool, we provide an overview of allelopathy in Triticum spp., to stimulate further coordinated breeding-oriented studies, to favor allelopathy exploitation for the sustainable cultivation of wheat, and in particular, to achieve improved biological weed control. PMID:24065979

Fragasso, Mariagiovanna; Iannucci, Anna; Papa, Roberto

2013-01-01

195

Durum wheat and allelopathy: toward wheat breeding for natural weed management.  

PubMed

Wheat-derived foodstuffs represent about one-fifth of the calories consumed by humans worldwide. Bread wheat (Triticum aestivum L.) is one of the most important crops throughout the world, and it has been extensively studied for its allelopathic potential. In contrast, for allelopathy in durum wheat (Triticum turgidum ssp. durum), our knowledge is partial and fragmentary. Through highlighting recent advances in using allelopathy as a crop-breeding tool, we provide an overview of allelopathy in Triticum spp., to stimulate further coordinated breeding-oriented studies, to favor allelopathy exploitation for the sustainable cultivation of wheat, and in particular, to achieve improved biological weed control. PMID:24065979

Fragasso, Mariagiovanna; Iannucci, Anna; Papa, Roberto

2013-01-01

196

Selective uptake of boronophenylalanine by glioma stem/progenitor cells.  

PubMed

The success of boron neutron capture therapy (BNCT) depends on the amount of boron in cells and the tumor/blood and tumor/(normal tissue) boron concentration ratios. For the first time, measurements of boron uptake in both stem/progenitor and differentiated glioma cells were performed along with measurements of boron biodistribution in suitable animal models. In glioma stem/progenitor cells, the selective accumulation of boronophenylalanine (BPA) was lower, and retention of boron after BPA removal was longer than in differentiated glioma cells in vitro. However, boron biodistribution was not statistically significantly different in mice with xenografts. PMID:22728842

Sun, Ting; Zhou, Youxin; Xie, Xueshun; Chen, Guilin; Li, Bin; Wei, Yongxin; Chen, Jinming; Huang, Qiang; Du, Ziwei

2012-08-01

197

Possible Progenitor of Special Supernova Type Detected  

NASA Astrophysics Data System (ADS)

Using data from NASA's Chandra X-ray Observatory, scientists have reported the possible detection of a binary star system that was later destroyed in a supernova explosion. The new method they used provides great future promise for finding the detailed origin of these important cosmic events. In an article appearing in the February 14th issue of the journal Nature, Rasmus Voss of the Max Planck Institute for Extraterrestrial Physics in Germany and Gijs Nelemans of Radboud University in the Netherlands searched Chandra images for evidence of a much sought after, but as yet unobserved binary system - one that was about to go supernova. Near the position of a recently detected supernova, they discovered an object in Chandra images taken more than four years before the explosion. Optical image of SN 2007on Optical image of SN 2007on The supernova, known as SN 2007on, was identified as a Type Ia supernova. Astronomers generally agree that Type Ia supernovas are produced by the explosion of a white dwarf star in a binary star system. However, the exact configuration and trigger for the explosion is unclear. Is the explosion caused by a collision between two white dwarfs, or because a white dwarf became unstable by pulling too much material off a companion star? Answering such questions is a high priority because Type Ia supernovas are major sources of iron in the Universe. Also, because of their nearly uniform intrinsic brightness, Type Ia supernova are used as important tools by scientists to study the nature of dark energy and other cosmological issues. People Who Read This Also Read... Oldest Known Objects Are Surprisingly Immature Black Holes Have Simple Feeding Habits Discovery of Most Recent Supernova in Our Galaxy Geriatric Pulsar Still Kicking "Right now these supernovas are used as black boxes to measure distances and derive the rate of expansion of the universe," said Nelemans. "What we're trying to do is look inside the box." If the supernova explosion is caused by material being pulled off a companion star onto the white dwarf, fusion of this material on the surface of the star should heat the star and produce a strong source of X-radiation prior to the explosion. Once the supernova explosion occurs, the white dwarf is expected to be completely destroyed and then would be undetectable in X-rays. In the merger scenario, the intensity of X-ray emission prior to the explosion is expected to be much weaker. Based on the detection of a fairly strong X-ray source at approximately the position of SN 2007on 4 years before the explosion, Voss and Nelemans conclude that the data support the scenario where matter is pulled off a companion star. The small number of X-ray sources in the field implies that there is only a small chance of an unrelated source being so close by coincidence. Also, the X-ray source has similar properties to those expected for fusion on a white dwarf, unlike most X-ray sources in the sky. However, in follow-up studies, Voss, Nelemans and colleagues Gijs Roelofs (Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass.) and Cees Bassa (McGill University, Canada) used higher-quality optical images to better determine the supernova's position. This work, which is not yet published, shows a small, but significant difference in the measured positions of the supernova and the X-ray source, suggesting the source may not be the progenitor. Follow-up Chandra observations hint that the X-ray object has disappeared, but further observations are needed to finally decide whether the source was the progenitor or not. The team is also applying this new method to other supernovas and has high hopes that they will eventually succeed in identifying the elusive cause of at least some of these explosions. "We're very excited about opening up a new way of studying supernovas, even though we're not sure that we've seen this particular stellar bomb before it exploded," said Gijs Roelofs. "We're very confident that we'll learn a lot more about these important supernovas in the future.&

2008-04-01

198

Gene loss, silencing and activation in a newly synthesized wheat allotetraploid.  

PubMed Central

We analyzed the events that affect gene structure and expression in the early stages of allopolyploidy in wheat. The transcriptome response was studied by analyzing 3072 transcripts in the first generation of a synthetic allotetraploid (genome S(l)S(l)A(m)A(m)), which resembles tetraploid wheat (genome BBAA), and in its two diploid progenitors Aegilops sharonensis (S(l)S(l)) and Triticum monococcum ssp. aegilopoides (A(m)A(m)). The expression of 60 out of 3072 transcripts was reproducibly altered in the allotetraploid: 48 transcripts disappeared and 12 were activated. Transcript disappearance was caused by gene silencing or by gene loss. Gene silencing affected one or both homeologous loci and was associated in part with cytosine methylation. Gene loss or methylation had occurred already in the F(1) intergeneric hybrid or in the allotetraploid, depending on the locus. The silenced/lost genes included rRNA genes and genes involved in metabolism, disease resistance, and cell cycle regulation. The activated genes with a known function were all retroelements. These findings show that wide hybridization and chromosome doubling affect gene expression via genetic and epigenetic alterations immediately upon allopolyploid formation. These events contribute to the genetic diploidization of newly formed allopolyploids. PMID:11973318

Kashkush, Khalil; Feldman, Moshe; Levy, Avraham A

2002-01-01

199

Wheat Flour Tortilla: Quality Prediction and Study of Physical and Textural Changes during Storage  

E-print Network

and tortillas were compared using five wheat samples. Refined flour doughs were more extensible and softer than whole wheat flour doughs. Whole wheat flour tortillas were larger, thinner and less opaque than refined flour tortillas. Refined wheat flour had much...

Ribeiro De Barros, Frederico

2010-07-14

200

Chromosome arm-specific BAC end sequences permit comparative analysis of homoeologous chromosomes and genomes of polyploid wheat  

PubMed Central

Background Bread wheat, one of the world’s staple food crops, has the largest, highly repetitive and polyploid genome among the cereal crops. The wheat genome holds the key to crop genetic improvement against challenges such as climate change, environmental degradation, and water scarcity. To unravel the complex wheat genome, the International Wheat Genome Sequencing Consortium (IWGSC) is pursuing a chromosome- and chromosome arm-based approach to physical mapping and sequencing. Here we report on the use of a BAC library made from flow-sorted telosomic chromosome 3A short arm (t3AS) for marker development and analysis of sequence composition and comparative evolution of homoeologous genomes of hexaploid wheat. Results The end-sequencing of 9,984 random BACs from a chromosome arm 3AS-specific library (TaaCsp3AShA) generated 11,014,359?bp of high quality sequence from 17,591 BAC-ends with an average length of 626?bp. The sequence represents 3.2% of t3AS with an average DNA sequence read every 19?kb. Overall, 79% of the sequence consisted of repetitive elements, 1.38% as coding regions (estimated 2,850 genes) and another 19% of unknown origin. Comparative sequence analysis suggested that 70-77% of the genes present in both 3A and 3B were syntenic with model species. Among the transposable elements, gypsy/sabrina (12.4%) was the most abundant repeat and was significantly more frequent in 3A compared to homoeologous chromosome 3B. Twenty novel repetitive sequences were also identified using de novo repeat identification. BESs were screened to identify simple sequence repeats (SSR) and transposable element junctions. A total of 1,057 SSRs were identified with a density of one per 10.4?kb, and 7,928 junctions between transposable elements (TE) and other sequences were identified with a density of one per 1.39?kb. With the objective of enhancing the marker density of chromosome 3AS, oligonucleotide primers were successfully designed from 758 SSRs and 695 Insertion Site Based Polymorphisms (ISBPs). Of the 96 ISBP primer pairs tested, 28 (29%) were 3A-specific and compared to 17 (18%) for 96 SSRs. Conclusion This work reports on the use of wheat chromosome arm 3AS-specific BAC library for the targeted generation of sequence data from a particular region of the huge genome of wheat. A large quantity of sequences were generated from the A genome of hexaploid wheat for comparative genome analysis with homoeologous B and D genomes and other model grass genomes. Hundreds of molecular markers were developed from the 3AS arm-specific sequences; these and other sequences will be useful in gene discovery and physical mapping. PMID:22559868

2012-01-01

201

Detection of irradiated wheat by germination  

NASA Astrophysics Data System (ADS)

A 5—day germination test was used to identify irradiated wheat. Wheat was irradiated and then germinated in dishes at 25-28°C for 5 days. Germination was inhibited with the dose of 3.3 kGy. Almost all grains did not germinate at 10 kGy. The growth of shoots and roots was retarded at 0.33 kGy and seriously inhibited at 0.5 kGy or over. The average lentgh of shoots at 0.5 kGy was about 20 mm and the shoots failed to grow. This effect was irreversible during postirradiation storage. It is a good index for identification of irradiated wheat. The effects of wheat varieties and old seed on germination were studied.

Zhu, S.; Kume, T.; Ishigaki, I.

1993-07-01

202

Two phase sampling for wheat acreage estimation  

NASA Technical Reports Server (NTRS)

A two-phase Landsat-based sample allocation and wheat proportion estimation method was developed. The technique employs manual, Landsat full frame-based wheat or cultivated land proportion estimates from a large number of segments comprising a first sample phase to optimally allocate a small phase-two sample of computer or manually processed segments. Proportion estimates from each phase are then linked by regression or probability proportional to estimated size estimators to provide wheat proportion estimates and standard errors by reporting unit. Application to the Kansas Southwest CRD (Crop Reporting District) for 1974 produced a wheat acreage estimate for that CRD within 2.42% of the USDA SRS-based estimate using a lower CRD inventory budget than for a simulated reference LACIE (Large Area Crop Inventory Experiment) system.

Thomas, R. W.; Hay, C. M.

1977-01-01

203

Wheat domestication: lessons for the future.  

PubMed

Wheat was one of the first crops to be domesticated more than 10,000 years ago in the Middle East. Molecular genetics and archaeological data have allowed the reconstruction of plausible domestication scenarios leading to modern cultivars. For diploid einkorn and tetraploid durum wheat, a single domestication event has likely occurred in the Karacadag Mountains, Turkey. Following a cross between tetraploid durum and diploid T. tauschii, the resultant hexaploid bread wheat was domesticated and disseminated around the Caucasian region. These polyploidisation events facilitated wheat domestication and created genetic bottlenecks, which excluded potentially adaptive alleles. With the urgent need to accelerate genetic progress to confront the challenges of climate change and sustainable agriculture, wild ancestors and old landraces represent a reservoir of underexploited genetic diversity that may be utilized through modern breeding methods. Understanding domestication processes may thus help identifying new strategies. PMID:21377616

Charmet, Gilles

2011-03-01

204

Determinants of Wheat Import Demand: Pakistan.  

National Technical Information Service (NTIS)

Pakistan is one of Asia's major producers and consumers of wheat. Recent trends indicate significant growth in future imports under current policies. The United States has historically dominated the Pakistani market because government purchase procedures ...

M. Ash, R. Landes

1993-01-01

205

Regeneration of Hippocampal Pyramidal Neurons after Ischemic Brain Injury by Recruitment of Endogenous Neural Progenitors  

Microsoft Academic Search

The adult brain is extremely vulnerable to various insults. The recent discovery of neural progenitors in adult mammals, however, raises the possibility of repairing damaged tissue by recruiting their latent regenerative potential. Here we show that activation of endogenous progenitors leads to massive regeneration of hippocampal pyramidal neurons after ischemic brain injury. Endogenous progenitors proliferate in response to ischemia and

Hirofumi Nakatomi; Toshihiko Kuriu; Shigeo Okabe; Shin-ichi Yamamoto; Osamu Hatano; Nobutaka Kawahara; Akira Tamura; Takaaki Kirino; Masato Nakafuku

2002-01-01

206

CULTIVAR DESCRIPTION CDC Clair winter wheat  

E-print Network

of the Canada Western Red Winter Wheat class. Key words: Triticum aestivum L., cultivar description, wheat est un blé d'automne (Triticum aestivum L.) demi-nain à rendement élevé et à paille forte, doté d de l'ouest canadien (BAROC). Mots clés: Triticum aestivum L., description de cultivar, blé (d

Saskatchewan, University of

207

Analysis of the wheat endosperm transcriptome  

Microsoft Academic Search

Among the cereals, wheat is the most widely grown geographically and is part of the staple diet in much of the world. Understanding\\u000a how the cereal endosperm develops and functions will help generate better tools to manipulate grain qualities important to\\u000a end-users. We used a genomics approach to identify and characterize genes that are expressed in the wheat endosperm. We

Debbie L. Laudencia-Chingcuanco; Boryana S. Stamova; Gerard R. Lazo; Xiangqin Cui; Olin D. Anderson

2006-01-01

208

Wheat Production in the Panhandle of Texas.  

E-print Network

seedlings usually will provide more grazing for livestock and produce a better cover for protection against blowing, but there are sev- eral disadvantages to early seeding. Early-seeded wheat may deplete the soil of most of the available moisture during... seedlings usually will provide more grazing for livestock and produce a better cover for protection against blowing, but there are sev- eral disadvantages to early seeding. Early-seeded wheat may deplete the soil of most of the available moisture during...

Whitfield, Charles J. (Charles James); Atkins, Irvin Milburn; Porter, Kenneth B.

1952-01-01

209

Wheat yield forecasts using Landsat data  

NASA Technical Reports Server (NTRS)

Leaf area index and percentage of vegetative cover, two indices of crop yield developed from Landsat multispectral scanning data, are discussed. Studies demonstrate that the Landsat indicators may be as highly correlated with winter wheat yield as estimates based on traditional field sampling methods; in addition, the Landsat indicators may account for variations in individual field yield which are not explainable by meteorological data. A simple technique employing early-season Landsat data to make wheat yield predictions is also considered.

Colwell, J. E.; Rice, D. P.; Nalepka, R. F.

1977-01-01

210

Rustproofing wheat for a changing climate  

Microsoft Academic Search

This paper offers projections of potential effects of climate change on rusts of wheat and how we should factor in a changing\\u000a climate when planning for the future management of these diseases. Even though the rusts of wheat have been extensively studied\\u000a internationally, there is a paucity of information on the likely effects of a changing climate on the rusts

Sukumar Chakraborty; Jo Luck; Grant Hollaway; Glenn Fitzgerald; Neil White

2011-01-01

211

The Impact of the CIMMYT Wheat Breeding Program on Wheat Yields in Mexico's Yaqui Valley, 1990-2002: Implications for the Future of Public Wheat Breeding  

Microsoft Academic Search

CIMMYT has invested a large and significant amount of public expenditures in wheat breeding research each year for several decades. Estimates of the impact of the wheat breeding program on wheat yield increases provides information to scientists, administrators, and policy makers regarding the efficacy and the rate of return to these investments, providing important information for future funding decisions. Using

Lawton Lanier Nalley; Andrew P. Barkley

2007-01-01

212

Isolation of Distinct Progenitor Stem Cell Populations from Dental Pulp  

Microsoft Academic Search

The present study compared the cellular characteristics of progenitor stem cell populations present in adult dental pulp, isolated by different methods utilizing 2 different features of stem cell biology. One population expressing high levels of ?1 integrin was isolated by preferential selection of adherent cells to fibronectin over 20 min. In an alternative approach, cells expressing the embryonic neural crest

Rachel J. Waddington; Sarah J. Youde; Chi P. Lee; Alastair J. Sloan

2009-01-01

213

[Research and clinical applications regarding endothelial progenitor cell transplantation].  

PubMed

Endothelial injury or dysfunction leads to multiple cardiovascular diseases, such as atherosclerosis, myocardial infarction, stroke, hypertension and peripheral vascular disease. Endothelial progenitor cells (EPCs) are precursor cells of endothelial cells, including the early endothelial progenitor cells and the late endothelial progenitor cells. Th ese two EPC types have diff erent function and surface markers. EPC in this article mainly means late endothelial progenitors which could grow into endothelial cloning and form vessels in vivo. Late EPCs can express CD133, CD31, KDR, CD144, CD34 etc, take in low density lipoprotein, bind with ulex europaeus lectin 1 and form blood vessels in vitro and in vivo. EPCs not only participate in new blood vessels formation, but also are closely related to the repair of damaged endothelium. Many studies confi rm that the transplanted EPCs are able to be mobilized to vascular injury location and repair the damaged endothelial cells thus promote new blood vessel formation, which provides a promising strategy for the treatment of cardiovascular diseases and ischemic diseases. PMID:25432379

Tan, Kefang; Sun, Xuan

2014-11-01

214

In vitro pancreas organogenesis from dispersed mouse embryonic progenitors.  

PubMed

The pancreas is an essential organ that regulates glucose homeostasis and secretes digestive enzymes. Research on pancreas embryogenesis has led to the development of protocols to produce pancreatic cells from stem cells (1). The whole embryonic organ can be cultured at multiple stages of development (2-4). These culture methods have been useful to test drugs and to image developmental processes. However the expansion of the organ is very limited and morphogenesis is not faithfully recapitulated since the organ flattens. We propose three-dimensional (3D) culture conditions that enable the efficient expansion of dissociated mouse embryonic pancreatic progenitors. By manipulating the composition of the culture medium it is possible to generate either hollow spheres, mainly composed of pancreatic progenitors expanding in their initial state, or, complex organoids which progress to more mature expanding progenitors and differentiate into endocrine, acinar and ductal cells and which spontaneously self-organize to resemble the embryonic pancreas. We show here that the in vitro process recapitulates many aspects of natural pancreas development. This culture system is suitable to investigate how cells cooperate to form an organ by reducing its initial complexity to few progenitors. It is a model that reproduces the 3D architecture of the pancreas and that is therefore useful to study morphogenesis, including polarization of epithelial structures and branching. It is also appropriate to assess the response to mechanical cues of the niche such as stiffness and the effects on cell´s tensegrity. PMID:25079453

Greggio, Chiara; De Franceschi, Filippo; Figueiredo-Larsen, Manuel; Grapin-Botton, Anne

2014-01-01

215

Bovine Mammary Progenitor Cells: Current Concepts and Future Directions  

Microsoft Academic Search

Although cell number is positively correlated with milk production, much remains to be learned about the bovine mammary stem cell and progenitor cells. Bovine mammary development is driven by many of the same classic mammogenic hormones studied in murine models, yet histologic features of bovine mammary development differ from that of rodent models. Most notably, terminal end buds, as they

A. V. Capuco; S. Ellis

2005-01-01

216

Precancerous Stem Cells Can Serve As Tumor Vasculogenic Progenitors  

Microsoft Academic Search

Tumor neo-vascularization is critical for tumor growth, invasion and metastasis, which has been considered to be mediated by a mechanism of angiogenesis. However, histopathological studies have suggested that tumor cells might be the progenitor for tumor vasculature. Recently, we have reported that the precancerous stem cells (pCSCs) representing the early stage of developing cancer stem cells (CSCs), have the potential

Rulong Shen; Yin Ye; Li Chen; Qingtao Yan; Sanford H. Barsky; Jian-Xin Gao

2008-01-01

217

Material-based deployment enhances efficacy of endothelial progenitor cells  

PubMed Central

Cell-based therapies are attractive for revascularizing and regenerating tissues and organs, but clinical trials of endothelial progenitor cell transplantation have not resulted in consistent benefit. We propose a different approach in which a material delivery system is used to create a depot of vascular progenitor cells in vivo that exit over time to repopulate the damaged tissue and participate in regeneration of a vascular network. Microenvironmental conditions sufficient to maintain the viability and outward migration of outgrowth endothelial cells (OECs) have been delineated, and a material incorporating these signals improved engraftment of transplanted cells in ischemic murine hindlimb musculature, and increased blood vessel densities from 260 to 670 vessels per mm2, compared with direct cell injection. Further, material deployment dramatically improved the efficacy of these cells in salvaging ischemic murine limbs, whereas bolus OEC delivery was ineffective in preventing toe necrosis and foot loss. Finally, material deployment of a combination of OECs with another cell population commonly isolated from peripheral or cord blood, endothelial progenitor cells (EPCs) returned perfusion to normal levels in 40 days, and prevented toe and foot necrosis. Direct injection of an EPC/OEC combination was minimally effective in improving limb perfusion, and untreated limbs underwent autoamputation in 3 days. These results demonstrate that vascular progenitor cell utility is highly dependent on the mode of delivery, and suggest that one can create new vascular beds for a variety of applications with this material-controlled deployment of cells. PMID:18794520

Silva, Eduardo A.; Kim, Eun-Suk; Kong, Hyun Joon; Mooney, David J.

2008-01-01

218

Type IIb Supernovae with Compact and Extended Progenitors  

NASA Astrophysics Data System (ADS)

The classic example of a Type IIb supernova is SN 1993J, which had a cool extended progenitor surrounded by a dense wind. There is evidence for another category of Type IIb supernova that has a more compact progenitor with a lower density, probably fast, wind. Distinguishing features of the compact category are weak optical emission from the shock heated envelope at early times, nonexistent or very weak H emission in the late nebular phase, rapidly evolving radio emission, rapid expansion of the radio shell, and expected nonthermal as opposed to thermal X-ray emission. Type IIb supernovae that have one or more of these features include SNe 1996cb, 2001ig, 2003bg, 2008ax, and 2008bo. All of these with sufficient radio data (the last four) show evidence for presupernova wind variability. We estimate a progenitor envelope radius ~1 × 1011 cm for SN 2008ax, a value consistent with a compact Wolf-Rayet progenitor. Supernovae in the SN 1993J extended category include SN 2001gd and probably the Cas A supernova. We suggest that the compact Type IIb events be designated Type cIIb and the extended ones Type eIIb. The H envelope mass dividing these categories is ~0.1 M sun.

Chevalier, Roger A.; Soderberg, Alicia M.

2010-03-01

219

Type IIb Supernovae with Compact and Extended Progenitors  

NASA Astrophysics Data System (ADS)

The classic example of a Type IIb supernova is SN 1993J, which had a cool extended progenitor surrounded by a dense wind. There is evidence for another category of Type IIb supernova which has a more compact progenitor with a lower density, probably fast, wind. Distinguishing features of the compact category are: weak optical emission from the shock heated envelope at early times; nonexistent or very weak H emission in the late nebular phase; rapidly evolving radio emission; rapid expansion of the radio shell; and expected nonthermal as opposed to thermal X-ray emission. Type IIb supernovae that have one or more of these features include SNe 1996cb, 2001ig, 2003bg, 2008ax, and 2008bo. All of these with sufficient radio data (the last four) show evidence for presupernova wind variability. We estimate a progenitor envelope radius 1e11 cm for SN 2008ax, a value consistent with a compact Wolf-Rayet progenitor. Supernovae in the SN 1993J extended category include SN 2001gd and probably the Cas A supernova. We suggest that the compact Type IIb events be designated Type cIIb and the extended ones Type eIIb. We acknowledge support from the NSF (RAC) and a Hubble Fellowship (AMS).

Chevalier, Roger; Soderberg, A.

2010-02-01

220

?4 Integrin signaling induces expansion of prostate tumor progenitors  

PubMed Central

The contextual signals that regulate the expansion of prostate tumor progenitor cells are poorly defined. We found that a significant fraction of advanced human prostate cancers and castration-resistant metastases express high levels of the ?4 integrin, which binds to laminin-5. Targeted deletion of the signaling domain of ?4 inhibited prostate tumor growth and progression in response to loss of p53 and Rb function in a mouse model of prostate cancer (PB-TAg mice). Additionally, it suppressed Pten loss-driven prostate tumorigenesis in tissue recombination experiments. We traced this defect back to an inability of signaling-defective ?4 to sustain self-renewal of putative cancer stem cells in vitro and proliferation of transit-amplifying cells in vivo. Mechanistic studies indicated that mutant ?4 fails to promote transactivation of ErbB2 and c-Met in prostate tumor progenitor cells and human cancer cell lines. Pharmacological inhibition of ErbB2 and c-Met reduced the ability of prostate tumor progenitor cells to undergo self-renewal in vitro. Finally, we found that ?4 is often coexpressed with c-Met and ErbB2 in human prostate cancers and that combined pharmacological inhibition of these receptor tyrosine kinases exerts antitumor activity in a mouse xenograft model. These findings indicate that the ?4 integrin promotes prostate tumorigenesis by amplifying ErbB2 and c-Met signaling in tumor progenitor cells. PMID:23348745

Yoshioka, Toshiaki; Otero, Javier; Chen, Yu; Kim, Young-Mi; Koutcher, Jason A.; Satagopan, Jaya; Reuter, Victor; Carver, Brett; de Stanchina, Elisa; Enomoto, Katsuhiko; Greenberg, Norman M.; Scardino, Peter T.; Scher, Howard I.; Sawyers, Charles L.; Giancotti, Filippo G.

2013-01-01

221

Behavioral heterogeneity of adult mouse lung epithelial progenitor cells.  

PubMed

The existence and identity of multipotent stem cells in the adult lung is currently highly debated. At present, it remains unclear whether candidate stem/progenitor cells are located in the airways, alveoli, or throughout the epithelial lining of the lung. Here, we introduce a method of airway microdissection, which enabled us to study the progenitor behavior of pulmonary epithelial cells in region-specific contexts. The progenitor characteristics of epithelial cells isolated from the trachea, proximal and distal airways, and lung parenchyme were evaluated in vitro and in vivo. We identified a population of airway-derived basal-like epithelial cells with the potential to self-renew and differentiate into airway and alveolar lineages in culture and in vivo after subcutaneous transplantation. The multipotent candidate progenitors originated from a minor fraction of the airway epithelial cell population characterized by high expression of ?6 integrin. Results of the current study provide new insights into the regenerative potential of region-specific integrin ?6-positive pulmonary epithelial cells. PMID:24950291

Chernaya, Olga; Shinin, Vasily; Liu, Yuru; Minshall, Richard D

2014-11-15

222

Translation Initiation Factor 4E Inhibits Differentiation of Erythroid Progenitors  

PubMed Central

Stem cell factor (SCF) delays differentiation and enhances the expansion of erythroid progenitors. Previously, we performed expression-profiling experiments to link signaling pathways to target genes using polysome-bound mRNA. SCF-induced phosphoinositide-3-kinase (PI3K) appeared to control polysome recruitment of specific mRNAs associated with neoplastic transformation. To evaluate the role of mRNA translation in the regulation of expansion versus differentiation of erythroid progenitors, we examined the function of the eukaryote initiation factor 4E (eIF4E) in these cells. SCF induced a rapid and complete phosphorylation of eIF4E-binding protein (4E-BP). Overexpression of eIF4E did not induce factor-independent growth but specifically impaired differentiation into mature erythrocytes. Overexpression of eIF4E rendered polysome recruitment of mRNAs with structured 5? untranslated regions largely independent of growth factor and resistant to the PI3K inhibitor LY294002. In addition, overexpression of eIF4E rendered progenitors insensitive to the differentiation-inducing effect of LY294002, indicating that control of mRNA translation is a major pathway downstream of PI3K in the regulation of progenitor expansion. PMID:16166632

Blazquez-Domingo, Montserrat; Grech, Godfrey; von Lindern, Marieke

2005-01-01

223

Neutrophil survival and c-kit+ progenitor proliferation  

E-print Network

1 Neutrophil survival and c-kit+ progenitor proliferation in Staphylococcus aureus infected skin during the evolution of an abscess are not well defined. Using a mouse model of Staphylococcus aureus for wound resolution and bacterial clearance1,2 . This is especially the case during Staphylococcus aureus

Simon, Scott I.

224

Mesenchymal progenitor cells in the human umbilical cord  

Microsoft Academic Search

Mesenchymal progenitor or stem cells (MPCs) isolated from fetal blood, liver, and bone marrow are a population of multipotential cells that can proliferate and differentiate into multiple mesodermal tissues including bone, cartilage, muscle, ligament, tendon, fat, and stroma. The objective of this study was to isolate and characterize MPCs in the human umbilical cord. The suspensions of endothelial and subendothelial

J. W. Kim; S. Y. Kim; S. Y. Park; Y. M. Kim; J. M. Kim; M. H. Lee; H. M. Ryu

2004-01-01

225

ADAR1 promotes malignant progenitor reprogramming in chronic myeloid leukemia  

PubMed Central

The molecular etiology of human progenitor reprogramming into self-renewing leukemia stem cells (LSC) has remained elusive. Although DNA sequencing has uncovered spliceosome gene mutations that promote alternative splicing and portend leukemic transformation, isoform diversity also may be generated by RNA editing mediated by adenosine deaminase acting on RNA (ADAR) enzymes that regulate stem cell maintenance. In this study, whole-transcriptome sequencing of normal, chronic phase, and serially transplantable blast crisis chronic myeloid leukemia (CML) progenitors revealed increased IFN-? pathway gene expression in concert with BCR-ABL amplification, enhanced expression of the IFN-responsive ADAR1 p150 isoform, and a propensity for increased adenosine-to-inosine RNA editing during CML progression. Lentiviral overexpression experiments demonstrate that ADAR1 p150 promotes expression of the myeloid transcription factor PU.1 and induces malignant reprogramming of myeloid progenitors. Moreover, enforced ADAR1 p150 expression was associated with production of a misspliced form of GSK3? implicated in LSC self-renewal. Finally, functional serial transplantation and shRNA studies demonstrate that ADAR1 knockdown impaired in vivo self-renewal capacity of blast crisis CML progenitors. Together these data provide a compelling rationale for developing ADAR1-based LSC detection and eradication strategies. PMID:23275297

Jiang, Qingfei; Crews, Leslie A.; Barrett, Christian L.; Chun, Hye-Jung; Court, Angela C.; Isquith, Jane M.; Zipeto, Maria A.; Goff, Daniel J.; Minden, Mark; Sadarangani, Anil; Rusert, Jessica M.; Dao, Kim-Hien T.; Morris, Sheldon R.; Goldstein, Lawrence S. B.; Marra, Marco A.; Frazer, Kelly A.; Jamieson, Catriona H. M.

2013-01-01

226

Evaluation of a High-Speed Color Sorter for Segregation of Red and White Wheat  

Microsoft Academic Search

A high-speed color sorter has the potential to help wheat breeders purify their white wheat breeding lines and white wheat exporters to meet purity requirements of end users. For this reason, a commercial color sorter was evaluated for sorting mixed red and white wheat. Ten wheat blends containing 95% white and 5% red wheat by mass were produced by mixing

Melchor C. Pasikatan; Floyd E. Dowell

227

Effects on performance of ground wheat with or without insoluble fiber or whole wheat in sequential feeding for laying hens.  

PubMed

Sequential feeding (SF) is an innovative system for laying hens consisting of nutrients separating energy, protein, and calcium supplies to fulfill nutrient requirements at the relevant time of day. In previous studies, hens received whole wheat in the morning and a balancer diet (rich in protein and calcium) in the afternoon. To improve SF utilization, the aim was to substitute whole wheat in the morning by an alternative energy supply: ground wheat and ground corn, with or without a proportion of whole wheat and insoluble fiber. The goal was to obtain the advantages observed in previous experiments with whole wheat [bigger gizzard, thinner hens, reduced feed conversion ratio (FCR)]. Four hundred thirty-two ISA Brown hens were housed in collective cages from 20 to 35 wk of age divided into 8 different treatments: a continuous control diet, a sequential diet with whole wheat in the morning, 3 wheat-based diets (ground wheat, ground wheat and 20% whole wheat, and ground wheat with 5% insoluble fiber) and 3 ground corn-based (ground corn, ground corn and 20% whole wheat, and ground corn with 5% insoluble fiber) provided in the morning. All sequential regimens received the same balancer diet rich in protein and calcium in the afternoon. Whole wheat SF gave the best results with an improved FCR compared with continuous control and all other SF diets. Wheat- and corn-based diets showed intermediate results between whole wheat SF and continuous feeding. Gizzard weight was higher and hens were lighter than with conventional continuous feeding, leading to an average FCR improvement of 3.2% compared with a continuous control. Thus, it is possible in SF diets to substitute, at least partially, whole wheat by ground wheat or ground corn with added insoluble fiber or some whole wheat, allowing more flexibility and economic optimization. PMID:23960132

Traineau, M; Bouvarel, I; Mulsant, C; Roffidal, L; Launay, C; Lescoat, P

2013-09-01

228

Population Density and Distribution of Wheat Bugs Infesting Durum Wheat in Sardinia, Italy  

PubMed Central

Wheat is a very important crop in Italy, and is infested by wheat bugs belonging to the genera Eurygaster (Hemiptera: Scutellaridae) and Aelia (Hemiptera: Pentatomidae). Many wheat bug infestations have been reported in the north, south, and center of Italy, both in the past as well as recently. The present study was carried out in Sardinia, Italy, during two years (2007 and 2008). The objective of this study was to determine the species and distribution of wheat bugs in durum wheat fields in Sardinia, and to estimate their population density in order to know the incidence of the pest on the island. Sampling took place twice a year (May and June) in three zones, representative of durum wheat cropping in the island. Four species of wheat bugs were found; the predominant species was Eurygaster austriaca (Schrank), followed by Aelia germari (Kuster), Eurygaster maura L., and Aelia acuminata L. The average density of wheat bugs was low (1.1 individuals/m2), but in certain areas it was above the damage threshold (4 individuals/m2). For this reason, the conclusion of the study is that this pest should be monitored in order to control outbreaks and prevent their further spread. PMID:23906035

Salis, Luigi; Goula, Marta; Izquierdo, Jordi; Gordun, Elena

2013-01-01

229

Fas transduces dual apoptotic and trophic signals in hematopoietic progenitors.  

PubMed

Stem cells and progenitors are often required to realize their differentiation potential in hostile microenvironments. The Fas/Fas ligand (FasL) interaction is a major effector pathway of apoptosis, which negatively regulates the expansion of differentiated hematopoietic cells. The involvement of this molecular interaction in the function of hematopoietic stem and progenitor cells is not well understood. In the murine syngeneic transplant setting, both Fas and FasL are acutely upregulated in bone marrow-homed donor cells; however, the Fas(+) cells are largely insensitive to FasL-induced apoptosis. In heterogeneous populations of lineage-negative (lin(-)) bone marrow cells and progenitors isolated by counterflow centrifugal elutriation, trimerization of the Fas receptor enhanced the clonogenic activity. Inhibition of caspases 3 and 8 did not affect the trophic signals mediated by Fas, yet it efficiently blocked the apoptotic pathways. Fas-mediated tropism appears to be of physiological significance, as pre-exposure of donor cells to FasL improved the radioprotective qualities of hematopoietic progenitors, resulting in superior survival of myeloablated hosts. Under these conditions, the activity of long-term reconstituting cells was not affected, as determined in sequential secondary and tertiary transplants. Dual caspase-independent tropic and caspase-dependent apoptotic signaling place the Fas receptor at an important junction of activation and death. This regulatory mechanism of hematopoietic homeostasis activates progenitors to promote the recovery from aplasia and converts into a negative regulator in distal stages of cell differentiation. Disclosure of potential conflicts of interest is found at the end of this article. PMID:17872500

Pearl-Yafe, Michal; Stein, Jerry; Yolcu, Esma S; Farkas, Daniel L; Shirwan, Haval; Yaniv, Isaac; Askenasy, Nadir

2007-12-01

230

UPDATE ON THE CETUS POLAR STREAM AND ITS PROGENITOR  

SciTech Connect

We trace the Cetus Polar Stream (CPS) with blue horizontal branch and red giant stars from Data Release 8 of the Sloan Digital Sky Survey. Using a larger data set than was available previously, we are able to refine the measured distance and velocity to this tidal debris star stream in the south Galactic cap. Assuming that the tidal debris traces the progenitor's orbit, we fit an orbit to the CPS and find that the stream is confined between ?24 and 36 kpc on a rather polar orbit inclined 87° to the Galactic plane. The eccentricity of the orbit is 0.20, and the period is ?700 Myr. If we instead matched N-body simulations to the observed tidal debris, these orbital parameters would change by 10% or less. The CPS stars travel in the opposite direction to those from the Sagittarius tidal stream in the same region of the sky. Through N-body models of satellites on the best-fitting orbit, and assuming that mass follows light, we show that the stream width, line-of-sight depth, and velocity dispersion imply a progenitor of ?> 10{sup 8} M{sub ?}. However, the density of stars along the stream requires either a disruption time on the order of one orbit or a stellar population that is more centrally concentrated than the dark matter. We suggest that an ultrafaint dwarf galaxy progenitor could reproduce a large stream width and velocity dispersion without requiring a very recent deflection of the progenitor into its current orbit. We find that most Cetus stars have metallicities of –2.5 < [Fe/H] <–2.0, similar to the observed metallicities of the ultrafaint dwarfs. Our simulations suggest that the parameters of the dwarf galaxy progenitors, including their dark matter content, could be constrained by observations of their tidal tails through comparison of the debris with N-body simulations.

Yam, William; Carlin, Jeffrey L.; Newberg, Heidi Jo; Dumas, Julie; O'Malley, Erin; Newby, Matthew; Martin, Charles, E-mail: carlij@rpi.edu [Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)

2013-10-20

231

Tendon proper- and peritenon-derived progenitor cells have unique tenogenic properties  

PubMed Central

Introduction Multipotent progenitor populations exist within the tendon proper and peritenon of the Achilles tendon. Progenitor populations derived from the tendon proper and peritenon are enriched with distinct cell types that are distinguished by expression of markers of tendon and vascular or pericyte origins, respectively. The objective of this study was to discern the unique tenogenic properties of tendon proper- and peritenon-derived progenitors within an in vitro model. We hypothesized that progenitors from each region contribute differently to tendon formation; thus, when incorporated into a regenerative model, progenitors from each region will respond uniquely. Moreover, we hypothesized that cell populations like progenitors were capable of stimulating tenogenic differentiation, so we generated conditioned media from these cell types to analyze their stimulatory potentials. Methods Isolated progenitors were seeded within fibrinogen/thrombin gel-based constructs with or without supplementation with recombinant growth/differentiation factor-5 (GDF5). Early and late in culture, gene expression of differentiation markers and matrix assembly genes was analyzed. Tendon construct ultrastructure was also compared after 45 days. Moreover, conditioned media from tendon proper-derived progenitors, peritenon-derived progenitors, or tenocytes was applied to each of the three cell types to determine paracrine stimulatory effects of the factors secreted from each of the respective cell types. Results The cell orientation, extracellular domain and fibril organization of constructs were comparable to embryonic tendon. The tendon proper-derived progenitors produced a more tendon-like construct than the peritenon-derived progenitors. Seeded tendon proper-derived progenitors expressed greater levels of tenogenic markers and matrix assembly genes, relative to peritenon-derived progenitors. However, GDF5 supplementation improved expression of matrix assembly genes in peritenon progenitors and structurally led to increased mean fibril diameters. It also was found that peritenon-derived progenitors secrete factor(s) stimulatory to tenocytes and tendon proper progenitors. Conclusions Data demonstrate that, relative to peritenon-derived progenitors, tendon proper progenitors have greater potential for forming functional tendon-like tissue. Furthermore, factors secreted by peritenon-derived progenitors suggest a trophic role for this cell type as well. Thus, these findings highlight the synergistic potential of including these progenitor populations in restorative tendon engineering strategies. PMID:25005797

2014-01-01

232

Testing and validating the CERES-wheat (Crop Estimation through Resource and Environment Synthesis-wheat) model in diverse environments  

NASA Technical Reports Server (NTRS)

CERES-Wheat is a computer simulation model of the growth, development, and yield of spring and winter wheat. It was designed to be used in any location throughout the world where wheat can be grown. The model is written in Fortran 77, operates on a daily time stop, and runs on a range of computer systems from microcomputers to mainframes. Two versions of the model were developed: one, CERES-Wheat, assumes nitrogen to be nonlimiting; in the other, CERES-Wheat-N, the effects of nitrogen deficiency are simulated. The report provides the comparisons of simulations and measurements of about 350 wheat data sets collected from throughout the world.

Otter-Nacke, S.; Godwin, D. C.; Ritchie, J. T.

1986-01-01

233

Stem cell biology is population biology: differentiation of hematopoietic multipotent progenitors to common lymphoid and myeloid progenitors  

PubMed Central

The hematopoietic stem cell (HSC) system is a demand control system, with the demand coming from the organism, since the products of the common myeloid and lymphoid progenitor (CMP, CLP respectively) cells are essential for activity and defense against disease. We show how ideas from population biology (combining population dynamics and evolutionary considerations) can illuminate the feedback control of the HSC system by the fully differentiated products, which has recently been verified experimentally. We develop models for the penultimate differentiation of HSC Multipotent Progenitors (MPPs) into CLP and CMP and introduce two concepts from population biology into stem cell biology. The first concept is the Multipotent Progenitor Commitment Response (MPCR) which is the probability that a multipotent progenitor cell follows a CLP route rather than a CMP route. The second concept is the link between the MPCR and a measure of Darwinian fitness associated with organismal performance and the levels of differentiated lymphoid and myeloid cells. We show that many MPCRs are consistent with homeostasis, but that they will lead to different dynamics of cells and signals following a wound or injury and thus have different consequences for Darwinian fitness. We show how coupling considerations of life history to dynamics of the HSC system and its products allows one to compute the selective pressures on cellular processes. We discuss ways that this framework can be used and extended. PMID:23327512

2013-01-01

234

New Types of Wheat Chromosomal Structural Variations in Derivatives of Wheat-Rye Hybrids  

PubMed Central

Background Chromosomal rearrangements induced by wheat-rye hybridization is a very well investigated research topic. However, the structural alterations of wheat chromosomes in wheat-rye hybrids are seldom reported. Methodology/Principal Findings Octoploid triticale lines were derived from common wheat Triticum. aestivum L. ‘Mianyang11’×rye Secale cereale L. ‘Kustro’. Some progeny were obtained by the controlled backcrossing of triticale with ‘Mianyang11’ and common wheat T. aestivum L. ‘Chuannong27’ followed by self-fertilization. Fluorescence in situ hybridization (FISH) and genomic in situ hybridization (GISH) using Oligo-pSc119.2-1, Oligo-pTa535-1 and rye genomic DNA as probes were used to analyze the mitotic chromosomes of these progeny. Alterations of wheat chromosomes including 5A, 6A, 1B, 2B, 6B, 7B, 1D, 3D and 7D were observed. 5AL arm carrying intercalary Oligo-pSc119.2-1, Oligo-pTa535-1 or both Oligo-pSc119.2-1 and Oligo-pTa535-1 signals, 6AS, 1BS and 1DL arms containing terminal Oligo-pSc119.2-1 signal, 6BS and 3DS arms without terminal Oligo-pSc119.2-1 signal, 7BS without subtelomeric Oligo-pSc119.2-1 signal and 7DL with intercalary Oligo-pSc119.2-1 signal have been observed. However, these changed wheat chromosomes have not been detected in ‘Mianyang11’ and Chuannong 27. The altered 5A, 6A, 7B and 7D chromosomes in this study have not been reported and represent several new karyotype structures of common wheat chromosomes. Conclusions/Significance These rearranged wheat chromosomes in the present study afford some new genetic variations for wheat breeding program and are valuable materials for studying the biological function of tandem repetitive DNA sequences. PMID:25302962

Chen, Lei; Wang, Yangyang; Ren, Zhenglong; Fu, Shulan

2014-01-01

235

Early lineage restriction in temporally distinct populations of Mesp1 progenitors during mammalian heart development.  

PubMed

Cardiac development arises from two sources of mesoderm progenitors, the first heart field (FHF) and the second (SHF). Mesp1 has been proposed to mark the most primitive multipotent cardiac progenitors common for both heart fields. Here, using clonal analysis of the earliest prospective cardiovascular progenitors in a temporally controlled manner during early gastrulation, we found that Mesp1 progenitors consist of two temporally distinct pools of progenitors restricted to either the FHF or the SHF. FHF progenitors were unipotent, whereas SHF progenitors were either unipotent or bipotent. Microarray and single-cell PCR with reverse transcription analysis of Mesp1 progenitors revealed the existence of molecularly distinct populations of Mesp1 progenitors, consistent with their lineage and regional contribution. Together, these results provide evidence that heart development arises from distinct populations of unipotent and bipotent cardiac progenitors that independently express Mesp1 at different time points during their specification, revealing that the regional segregation and lineage restriction of cardiac progenitors occur very early during gastrulation. PMID:25150979

Lescroart, Fabienne; Chabab, Samira; Lin, Xionghui; Rulands, Steffen; Paulissen, Catherine; Rodolosse, Annie; Auer, Herbert; Achouri, Younes; Dubois, Christine; Bondue, Antoine; Simons, Benjamin D; Blanpain, Cédric

2014-09-01

236

miR-203 regulates progenitor cell proliferation during adult zebrafish retina regeneration.  

PubMed

Damage of the zebrafish retina triggers a spontaneous regeneration response that is initiated by Müller Glia (MG) dedifferentiation and asymmetric cell division to produce multipotent progenitor cells. Subsequent expansion of the progenitor pool by proliferation is critical for retina regeneration. Pax6b expression in the progenitor cells is necessary for their proliferation, but exact regulation of its expression is unclear. Here, we show that miR-203 is downregulated during regeneration in proliferating progenitor cells. Elevated miR-203 levels inhibit progenitor cell expansion without affecting MG dedifferentiation or progenitor cell generation. Using GFP-reporter assays and gain and loss of function experiments in the retina, we show that miR-203 expression must be suppressed to allow pax6b expression and subsequent progenitor cell proliferation. PMID:24858486

Rajaram, Kamya; Harding, Rachel L; Hyde, David R; Patton, James G

2014-08-15

237

agronomie: agriculture and environment A new disease of wheat caused  

E-print Network

1996) Summary — Late maturity wheat plants (Triticum aestivum L) culivars Trigomax and Buck. Alternaria leaf blight / wheat / Triticum aestivum / Alternaria triticimaculans Résumen — Une nueva enfermedad del trigo causada por Alternaria triticimaculans en Argentina. Plantas de trigo (Triticum aestivum

Paris-Sud XI, Université de

238

21 CFR 137.200 - Whole wheat flour.  

Code of Federal Regulations, 2011 CFR

...unaltered. To compensate for any natural deficiency of enzymes, malted wheat, malted wheat flour, malted barley...Fungal alpha -amylase,” “Fungal ?-amylase”, “Enzyme”, or “Enzyme added for improved baking”. When any optional...

2011-04-01

239

21 CFR 137.200 - Whole wheat flour.  

Code of Federal Regulations, 2012 CFR

...unaltered. To compensate for any natural deficiency of enzymes, malted wheat, malted wheat flour, malted barley...Fungal alpha -amylase,” “Fungal ?-amylase”, “Enzyme”, or “Enzyme added for improved baking”. When any optional...

2012-04-01

240

21 CFR 137.200 - Whole wheat flour.  

Code of Federal Regulations, 2013 CFR

...unaltered. To compensate for any natural deficiency of enzymes, malted wheat, malted wheat flour, malted barley...Fungal alpha -amylase,” “Fungal ?-amylase”, “Enzyme”, or “Enzyme added for improved baking”. When any optional...

2013-04-01

241

21 CFR 137.200 - Whole wheat flour.  

...unaltered. To compensate for any natural deficiency of enzymes, malted wheat, malted wheat flour, malted barley...Fungal alpha -amylase,” “Fungal ?-amylase”, “Enzyme”, or “Enzyme added for improved baking”. When any optional...

2014-04-01

242

21 CFR 137.200 - Whole wheat flour.  

Code of Federal Regulations, 2010 CFR

...unaltered. To compensate for any natural deficiency of enzymes, malted wheat, malted wheat flour, malted barley...Fungal alpha -amylase,” “Fungal ?-amylase”, “Enzyme”, or “Enzyme added for improved baking”. When any optional...

2010-04-01

243

21 CFR 139.180 - Wheat and soy noodle products.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Wheat and soy noodle products. 139.180 Section 139.180 ...HUMAN CONSUMPTION MACARONI AND NOODLE PRODUCTS Requirements for Specific Standardized Macaroni and Noodle Products § 139.180 Wheat and soy...

2010-04-01

244

Original article Competitive ability of wheat cultivars with wild oats  

E-print Network

Original article Competitive ability of wheat cultivars with wild oats depending on nitrogen ­ In a field experiment, wheat (Triticum aestivum L.) grew with the infesting weed wild oat (Avena sterilis ssp

Paris-Sud XI, Université de

245

Search for Type Ia supernova progenitors in open star clusters  

NASA Astrophysics Data System (ADS)

Though Type Ia supernovae (henceforth SNae) are a primary tool in refining our understanding of cosmology and dark energy, controversies still abound regarding what the progenitors of these SNae are. The two main classes of possible Type Ia SN progenitors are: (1) the single-degenerate model, where a white dwarf (the remnant of a Sun-like star that has completed its life cycle) gravitationally accretes material from a close companion star, and (2) the double-degenerate model, involving the merger of two white dwarfs. In either case, the resulting SN explosion looks the same superficially. But some of the details of the SNae, perhaps including details critical to understanding dark energy, may depend sensitively on what the progenitors are. The goal of this thesis was to search for radial velocity variations in two candidate double degenerate systems. Firstly, I determined if either of these systems were bona fide double degenerates. I used the well-tested method of searching for radial velocity variations due to orbital motion as determined by changing Doppler shifts in their optical spectra. These data were obtained from time-series spectra of both candidate systems over several hours at the world's largest ground based optical telescope, the Keck Observatory in Hawaii. Secondly, I tested whether each confirmed binary system is of sufficient mass and sufficiently short orbital period to be progenitors of a future Type Ia SN. Binary white dwarfs that will merge to form Type IaSNae over a Hubble time have orbital periods less than six hours, which are easily detectable with these data. Type Ia SN progenitors must also have a mass near or above the Chandrasekhar limit of ~1.44 solar masses; the total mass of these systems can also be determined from our data. If one or both of these candidate systems had met both these criteria, the white dwarfs would have been the first definitive examples of the double degenerate class of Type Ia progenitors. This result, which we refer to as a positive result, would have been extremely important and highly impactful in astronomical research.

Chakraborty, Subho

246

Plant Growth Inhibitory Compounds from Aqueous Leachate of Wheat Straw  

Microsoft Academic Search

When seedlings of lettuce, cress, rice and wheat were incubated with the leachate of wheat straw, the roots growth of lettuce\\u000a and garden cress were particularly inhibited. The leachate of wheat straw (100 g eq.\\/l) showed 80.5 and 79.4% inhibition for\\u000a lettuce and cress roots, respectively. The inhibitory activity was stronger as the concentration of wheat straw leachate was\\u000a greater. This

Hiroshi Nakano; Satoshi Morita; Hideyuki Shigemori; Koji Hasegawa

2006-01-01

247

Isolation, promoter analysis and expression profile of Dreb2 in response to drought stress in wheat ancestors.  

PubMed

Drought is one of the most important abiotic stresses, constraining crop production seriously. The dehydration responsive element binding proteins (DREBs) are important plant-specific transcription factors that respond to various abiotic stresses and consequently induce abiotic stress-related genes that impart stress endurance in plants. Wild species are naturally exposed to various abiotic stresses and potentially harbor suitable alleles through natural selection. In this study we isolated and characterized Dreb2 from Triticum urartu (GenBank: KF731664), Aegilops speltoides (GenBank: KF731665) and Aegilops tauschii (GenBank: KF731663), the A, B and D genome ancestors of bread wheat, respectively. Analysis of over 1.3 kb upstream region of the gene revealed the presence of several conserved cis-acting regulatory elements including ABA-responsive elements, low temperature responsive elements, and several light and environmental signaling related motifs potentially vindicate Dreb2 responses to environmental signals. Moreover, the gene exhibited an alternative splicing, conserved among orthologous genes in grasses, and produced a non-functional isoform due to splicing in an exon resulted frame-shift creating an early stop codon before the functional domain. The expression analysis of Dreb2 under normal and different levels of dehydration stress conditions indicated that the two active spliced isoforms are upregulated when the plant exposed to drought stress whereas the non-functional isoform is downregulated in severe drought. PMID:25017054

Tavakol, Elahe; Sardaro, Maria Luisa Savo; Shariati, J Vahid; Rossini, Laura; Porceddu, Enrico

2014-10-01

248

Isolation of a wheat (Triticum aestivum L.) mutant in ABA 8?-hydroxylase gene: effect of reduced ABA catabolism on germination inhibition under field condition  

PubMed Central

Pre-harvest sprouting, the germination of mature seeds on the mother plant under moist condition, is a serious problem in cereals. To investigate the effect of reduced abscisic acid (ABA) catabolism on germination in hexaploid wheat (Triticum aestivum L.), we cloned the wheat ABA 8?-hydroxyase gene which was highly expressed during seed development (TaABA8?OH1) and screened for mutations that lead to reduced ABA catabolism. In a screen for natural variation, one insertion mutation in exon 5 of TaABA8?OH1 on the D genome (TaABA8?OH1-D) was identified in Japanese cultivars including ‘Tamaizumi’. However, a single mutation in TaABA8?OH1-D had no clear effect on germination inhibition in double haploid lines. In a screen for a mutation, one deletion mutant lacking the entire TaABA8?OH1 on the A genome (TaABA8?OH1-A), TM1833, was identified from gamma-ray irradiation lines of ‘Tamaizumi’. TM1833 (a double mutant in TaABA8?OH1-A and TaABA8?OH1-D) showed lower TaABA8?OH1 expression, higher ABA content in embryos during seed development under field condition and lower germination than those in ‘Tamaizumi’ (a single mutant in TaABA8?OH1-D). These results indicate that reduced ABA catabolism through mutations in TaABA8?OH1 may be effective in germination inhibition in field-grown wheat. PMID:23641187

Chono, Makiko; Matsunaka, Hitoshi; Seki, Masako; Fujita, Masaya; Kiribuchi-Otobe, Chikako; Oda, Shunsuke; Kojima, Hisayo; Kobayashi, Daisuke; Kawakami, Naoto

2013-01-01

249

Isolation of a wheat (Triticum aestivum L.) mutant in ABA 8'-hydroxylase gene: effect of reduced ABA catabolism on germination inhibition under field condition.  

PubMed

Pre-harvest sprouting, the germination of mature seeds on the mother plant under moist condition, is a serious problem in cereals. To investigate the effect of reduced abscisic acid (ABA) catabolism on germination in hexaploid wheat (Triticum aestivum L.), we cloned the wheat ABA 8'-hydroxyase gene which was highly expressed during seed development (TaABA8'OH1) and screened for mutations that lead to reduced ABA catabolism. In a screen for natural variation, one insertion mutation in exon 5 of TaABA8'OH1 on the D genome (TaABA8'OH1-D) was identified in Japanese cultivars including 'Tamaizumi'. However, a single mutation in TaABA8'OH1-D had no clear effect on germination inhibition in double haploid lines. In a screen for a mutation, one deletion mutant lacking the entire TaABA8'OH1 on the A genome (TaABA8'OH1-A), TM1833, was identified from gamma-ray irradiation lines of 'Tamaizumi'. TM1833 (a double mutant in TaABA8'OH1-A and TaABA8'OH1-D) showed lower TaABA8'OH1 expression, higher ABA content in embryos during seed development under field condition and lower germination than those in 'Tamaizumi' (a single mutant in TaABA8'OH1-D). These results indicate that reduced ABA catabolism through mutations in TaABA8'OH1 may be effective in germination inhibition in field-grown wheat. PMID:23641187

Chono, Makiko; Matsunaka, Hitoshi; Seki, Masako; Fujita, Masaya; Kiribuchi-Otobe, Chikako; Oda, Shunsuke; Kojima, Hisayo; Kobayashi, Daisuke; Kawakami, Naoto

2013-03-01

250

21 CFR 139.138 - Whole wheat macaroni products.  

...macaroni products by § 139.110(a), (f)(2), (f)(3), and (g), except that: (1) Whole wheat flour or whole durum wheat flour or both are used as the sole wheat ingredient; and (2) None of the optional ingredients permitted...

2014-04-01

251

21 CFR 139.138 - Whole wheat macaroni products.  

Code of Federal Regulations, 2011 CFR

...macaroni products by § 139.110(a), (f)(2), (f)(3), and (g), except that: (1) Whole wheat flour or whole durum wheat flour or both are used as the sole wheat ingredient; and (2) None of the optional ingredients permitted...

2011-04-01

252

Haplotype diversity at fusarium head blight resistance QTLs in wheat  

Microsoft Academic Search

Fusarium head blight (FHB) reduces grain yield and quality in common and durum wheat. Host FHB resistance is an effective control measure that is achieved by stacking multiple resistance genes into a wheat line. Therefore, breeders would benefit from knowing which resistance sources carry different resistance genes. A diverse collection of FHB-resistant and -susceptible wheat lines was characterized with microsatellite

C. A. McCartney; D. J. Somers; G. Fedak; W. Cao

2004-01-01

253

Anisotropic Characteristics Analysis of Red Edge Parameters for Winter Wheat  

Microsoft Academic Search

Based on canopy hyperspectral bidirectional reflectance data and their ancillary parameters, bidirectional reflectance properties of winter wheat were analyzed in the visible and near infrared (VNIR) regions. The results show that winter wheat exhibit strong anisotropic characteristics in the solar principal plane. In addition, the bidirectional reflectance properties of winter wheat change in intensity and trend, because the canopy structural

Xuehong Zhang; Yansong Bao

254

Progenitors of type Ia supernovae in elliptical galaxies  

SciTech Connect

Although there is a nearly universal agreement that type Ia supernovae are associated with the thermonuclear disruption of a CO white dwarf, the exact nature of their progenitors is still unknown. The single degenerate scenario envisages a white dwarf accreting matter from a non-degenerate companion in a binary system. Nuclear energy of the accreted matter is released in the form of electromagnetic radiation or gives rise to numerous classical nova explosions prior to the supernova event. We show that combined X-ray output of supernova progenitors and statistics of classical novae predicted in the single degenerate scenario are inconsistent with X-ray and optical observations of nearby early type galaxies and galaxy bulges. White dwarfs accreting from a donor star in a binary system and detonating at the Chandrasekhar mass limit can account for no more than {approx}5% of type Ia supernovae observed in old stellar populations.

Gilfanov, M.; Bogdan, A.

2011-09-21

255

THE POPULATION OF HELIUM-MERGER PROGENITORS: OBSERVATIONAL PREDICTIONS  

SciTech Connect

The helium-merger gamma-ray burst (GRB) progenitor is produced by the rapid accretion onto a compact remnant (neutron star or black hole) when it undergoes a common envelope inspiral with its companion's helium core. This merger phase produces a very distinct environment around these outbursts and recent observations suggest that, in some cases, we are detecting the signatures of the past merger in the GRB afterglow. These observations allow us, for the first time, to study the specific features of the helium-merger progenitor. In this paper, we couple population synthesis calculations to our current understanding of GRB engines and common envelope evolution to make observational predictions for the helium-merger GRB population. Many mergers do not produce GRB outbursts and we discuss the implications of these mergers with the broader population of astrophysical transients.

Fryer, Chris L. [CCS Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)] [CCS Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Belczynski, Krzysztof; Bulik, Tomasz [Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warsaw (Poland)] [Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warsaw (Poland); Berger, Edo [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)] [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Thoene, Christina [IAA-CSIC, Glorieta de la Astronomia s/n, E-18008 Granada (Spain)] [IAA-CSIC, Glorieta de la Astronomia s/n, E-18008 Granada (Spain); Ellinger, Carola [Department of Physics, University of Texas at Arlington, 502 Yates Street, Box 19059, Arlington, TX 76019 (United States)] [Department of Physics, University of Texas at Arlington, 502 Yates Street, Box 19059, Arlington, TX 76019 (United States)

2013-02-20

256

Is Black-Hole Ringdown a Memory of Its Progenitor?  

NASA Astrophysics Data System (ADS)

We perform an extensive numerical study of coalescing black-hole binaries to understand the gravitational-wave spectrum of quasinormal modes excited in the merged black hole. Remarkably, we find that the masses and spins of the progenitor are clearly encoded in the mode spectrum of the ringdown signal. Some of the mode amplitudes carry the signature of the binary’s mass ratio, while others depend critically on the spins. Simulations of precessing binaries suggest that our results carry over to generic systems. Using Bayesian inference, we demonstrate that it is possible to accurately measure the mass ratio and a proper combination of spins even when the binary is itself invisible to a detector. Using a mapping of the binary masses and spins to the final black-hole spin allows us to further extract the spin components of the progenitor. Our results could have tremendous implications for gravitational astronomy by facilitating novel tests of general relativity using merging black holes.

Kamaretsos, Ioannis; Hannam, Mark; Sathyaprakash, B. S.

2012-10-01

257

The Mammary Gland Microenvironment Directs Progenitor Cell Fate In Vivo  

PubMed Central

The mammary gland is a unique organ that continually undergoes postnatal developmental changes. In mice, the mammary gland is formed via signals from terminal end buds, which direct ductal growth and elongation. Intriguingly, it is likely that the entire cellular repertoire of the mammary gland is formed from a single antecedent cell. Furthermore, in order to produce progeny of varied lineages (e.g., luminal and myoepithelial cells), signals from the local tissue microenvironment influence mammary stem/progenitor cell fate. Data have shown that cells from the mammary gland microenvironment reprogram adult somatic cells from other organs (testes, nerve) into cells that produce milk and express mammary epithelial cell proteins. Similar results were found for human tumorigenic epithelial carcinoma cells. Presently, it is unclear how the deterministic power of the mammary gland microenvironment controls epithelial cell fate. Regardless, signals generated by the microenvironment have a profound influence on progenitor cell differentiation in vivo. PMID:21647291

Bussard, Karen M.; Smith, Gilbert H.

2011-01-01

258

EVLA Constraints on the Progenitors of Supernovae Type Ia  

NASA Astrophysics Data System (ADS)

While Type Ia supernovae are used increasingly as cosmological probes to trace the expansion history of the Universe, the nature of their progenitors remains enshrouded in mystery. In the favored model for these explosions, a white dwarf accretes material from a hydrogen-rich donor star (e.g. red giant). A necessary implication of this model is the production of weak radio emission as the SN blastwave plows through the wind of the donor star. Previous radio searches for this signal have been unsuccessful, largely attributed to the fact that the expected emission lay just beyond the VLA sensitivity. Here we present recent results from our EVLA program, which utilizes the increased sensitivity to search for the expected signal from SNe Ia. The non-detection of radio emission with the EVLA would indicate double-degenerate progenitor systems (binary white dwarf) or require serious modifications to the single-degenerate model.

Chomiuk, Laura; Soderberg, A. M.; Chevalier, R.; Badenes, C.; Fransson, C.

2011-01-01

259

Transcriptional diversity during lineage commitment of human blood progenitors.  

PubMed

Blood cells derive from hematopoietic stem cells through stepwise fating events. To characterize gene expression programs driving lineage choice, we sequenced RNA from eight primary human hematopoietic progenitor populations representing the major myeloid commitment stages and the main lymphoid stage. We identified extensive cell type-specific expression changes: 6711 genes and 10,724 transcripts, enriched in non-protein-coding elements at early stages of differentiation. In addition, we found 7881 novel splice junctions and 2301 differentially used alternative splicing events, enriched in genes involved in regulatory processes. We demonstrated experimentally cell-specific isoform usage, identifying nuclear factor I/B (NFIB) as a regulator of megakaryocyte maturation-the platelet precursor. Our data highlight the complexity of fating events in closely related progenitor populations, the understanding of which is essential for the advancement of transplantation and regenerative medicine. PMID:25258084

Chen, Lu; Kostadima, Myrto; Martens, Joost H A; Canu, Giovanni; Garcia, Sara P; Turro, Ernest; Downes, Kate; Macaulay, Iain C; Bielczyk-Maczynska, Ewa; Coe, Sophia; Farrow, Samantha; Poudel, Pawan; Burden, Frances; Jansen, Sjoert B G; Astle, William J; Attwood, Antony; Bariana, Tadbir; de Bono, Bernard; Breschi, Alessandra; Chambers, John C; Choudry, Fizzah A; Clarke, Laura; Coupland, Paul; van der Ent, Martijn; Erber, Wendy N; Jansen, Joop H; Favier, Rémi; Fenech, Matthew E; Foad, Nicola; Freson, Kathleen; van Geet, Chris; Gomez, Keith; Guigo, Roderic; Hampshire, Daniel; Kelly, Anne M; Kerstens, Hindrik H D; Kooner, Jaspal S; Laffan, Michael; Lentaigne, Claire; Labalette, Charlotte; Martin, Tiphaine; Meacham, Stuart; Mumford, Andrew; Nürnberg, Sylvia; Palumbo, Emilio; van der Reijden, Bert A; Richardson, David; Sammut, Stephen J; Slodkowicz, Greg; Tamuri, Asif U; Vasquez, Louella; Voss, Katrin; Watt, Stephen; Westbury, Sarah; Flicek, Paul; Loos, Remco; Goldman, Nick; Bertone, Paul; Read, Randy J; Richardson, Sylvia; Cvejic, Ana; Soranzo, Nicole; Ouwehand, Willem H; Stunnenberg, Hendrik G; Frontini, Mattia; Rendon, Augusto

2014-09-26

260

Single luminal epithelial progenitors can generate prostate organoids in culture.  

PubMed

The intrinsic ability to exhibit self-organizing morphogenetic properties in ex vivo culture may represent a general property of tissue stem cells. Here we show that single luminal stem/progenitor cells can generate prostate organoids in a three-dimensional culture system in the absence of stroma. Organoids generated from CARNs (castration-resistant Nkx3.1-expressing cells) or normal prostate epithelia exhibit tissue architecture containing luminal and basal cells, undergo long-term expansion in culture and exhibit functional androgen receptor signalling. Lineage-tracing demonstrates that luminal cells are favoured for organoid formation and generate basal cells in culture. Furthermore, tumour organoids can initiate from CARNs after oncogenic transformation and from mouse models of prostate cancer, and can facilitate analyses of drug response. Finally, we provide evidence supporting the feasibility of organoid studies of human prostate tissue. Our studies underscore the progenitor properties of luminal cells, and identify in vitro approaches for studying prostate biology. PMID:25241035

Chua, Chee Wai; Shibata, Maho; Lei, Ming; Toivanen, Roxanne; Barlow, LaMont J; Bergren, Sarah K; Badani, Ketan K; McKiernan, James M; Benson, Mitchell C; Hibshoosh, Hanina; Shen, Michael M

2014-10-01

261

The Adventitia: A Dynamic Interface Containing Resident Progenitor Cells  

PubMed Central

Conventional views of the tunica adventitia as a poorly organized layer of vessel wall composed of fibroblasts, connective tissue and perivascular nerves are undergoing revision. Recent studies suggest that the adventitia has properties of a stem/progenitor cell niche in the artery wall that may be poised to respond to arterial injury. It is also a major site of immune surveillance and inflammatory cell trafficking, and harbors a dynamic microvasculature, the vasa vasorum, that maintains the medial layer and provides an important gateway for macrophage and leukocyte migration into the intima. In addition, the adventitia is in contact with tissue that surrounds the vessel and may actively participate in exchange of signals and cells between the vessel wall and the tissue in which it resides. This brief review highlights recent advances in our understanding of the adventitia and its resident progenitor cells and discusses progress toward an integrated view of adventitial function in vascular development, repair and disease. PMID:21677296

Majesky, Mark W.; Dong, Xiu Rong; Hoglund, Virginia; Mahoney, William M.; Daum, Guenter

2011-01-01

262

Is black-hole ringdown a memory of its progenitor?  

PubMed

We perform an extensive numerical study of coalescing black-hole binaries to understand the gravitational-wave spectrum of quasinormal modes excited in the merged black hole. Remarkably, we find that the masses and spins of the progenitor are clearly encoded in the mode spectrum of the ringdown signal. Some of the mode amplitudes carry the signature of the binary's mass ratio, while others depend critically on the spins. Simulations of precessing binaries suggest that our results carry over to generic systems. Using Bayesian inference, we demonstrate that it is possible to accurately measure the mass ratio and a proper combination of spins even when the binary is itself invisible to a detector. Using a mapping of the binary masses and spins to the final black-hole spin allows us to further extract the spin components of the progenitor. Our results could have tremendous implications for gravitational astronomy by facilitating novel tests of general relativity using merging black holes. PMID:23083233

Kamaretsos, Ioannis; Hannam, Mark; Sathyaprakash, B S

2012-10-01

263

Fate mapping by piggyBac transposase reveals that neocortical GLAST+ progenitors generate more astrocytes than Nestin+ progenitors in rat neocortex.  

PubMed

Progenitors within the neocortical ventricular zone (VZ) first generate pyramidal neurons and then astrocytes. We applied novel piggyBac transposase lineage tracking methods to fate-map progenitor populations positive for Nestin or glutamate and aspartate transpoter (GLAST) promoter activities in the rat neocortex. GLAST+ and Nestin+ progenitors at embryonic day 13 (E13) produce lineages containing similar rations of neurons and astrocytes. By E15, the GLAST+ progenitor population diverges significantly to produce lineages with 5-10-fold more astrocytes relative to neurons than generated by the Nestin+ population. To determine when birth-dated progeny within GLAST+ and Nestin+ populations diverge, we used a Cre/loxP fate-mapping system in which plasmids are lost after a cell division. By E18, birth-dated progeny of GLAST+ progenitors give rise to 2-3-fold more neocortical astrocytes than do Nestin+ progenitors. Finally, we used a multicolor clonal labeling method to show that the GLAST+ population labeled at E15 generates astrocyte progenitors that produce larger, spatially restricted, clonal clusters than the Nestin+ population. This study provides in vivo evidence that by mid-corticogenesis (E15), VZ progenitor populations have significantly diversified in terms of their potential to generate astrocytes and neurons. PMID:23118195

Siddiqi, Faez; Chen, Fuyi; Aron, Abraham W; Fiondella, Christopher G; Patel, Komal; LoTurco, Joseph J

2014-02-01

264

Stem and progenitor cell-mediated tumor selective gene therapy  

Microsoft Academic Search

The poor prognosis for patients with aggressive or metastatic tumors and the toxic side effects of currently available treatments necessitate the development of more effective tumor-selective therapies. Stem\\/progenitor cells display inherent tumor-tropic properties that can be exploited for targeted delivery of anticancer genes to invasive and metastatic tumors. Therapeutic genes that have been inserted into stem cells and delivered to

K S Aboody; J Najbauer; M K Danks

2008-01-01

265

Contribution of Endothelial Progenitor Cells to the Angiogenic Process  

Microsoft Academic Search

Among the molecular and cellular processes that orchestrate construction of new blood vessels, the distinct contribution of\\u000a circulating cells has recently become appreciated. The endothelial progenitor cell (EPC) was one of the first identified circulating\\u000a cell types found to directly contribute to neo-vessels walls. Subsequently, a complex network of signals between EPCs and\\u000a other circulating bone marrow-derived cell types has

Marco Seandel; Andrea T. Hooper; Shahin Rafii

266

High glucose downregulates endothelial progenitor cell number via SIRT1  

Microsoft Academic Search

Increasing evidence indicates that mammalian SIRT1 mediates calorie restriction and influences lifespan regulating a number of biological molecules such as FoxO1. SIRT1 controls the angiogenic activity of endothelial cells via deacetylation of FoxO1. Endothelial dysfunction and reduced new blood vessel growth in diabetes involve a decreased bioactivity of endothelial progenitor cells (EPCs) via repression of FoxO1 transcriptional activity. The relative

Maria Luisa Balestrieri; Monica Rienzo; Francesca Felice; Raffaele Rossiello; Vincenzo Grimaldi; Lara Milone; Amelia Casamassimi; Luigi Servillo; Bartolomeo Farzati; Alfonso Giovane; Claudio Napoli

2008-01-01

267

What are the progenitors of Galactic Bulge Planetary Nebulae?  

NASA Astrophysics Data System (ADS)

CLOUDY photoionization models of galactic bulge planetary nebulae are computed with the goal of simultaneously determing the luminosity and temperature of the planetary nebulae central stars and the abundances of He, C, N, O, Ne, S, Cl, and Ar in the nebulae. A synthetic stellarevolution model is employed to determine the zero age main sequence mass and composition of the planetary nebulae progenitor. The implications for stellar populations and the chemical evolution of the bulge are discussed.

Buell, James F.

2014-06-01

268

Mobilization of Stem Cells\\/Progenitor Cells by Physical Activity  

Microsoft Academic Search

\\u000a A number of publications have provided evidence that exercise and physical activity are linked to the activation, mobilization,\\u000a and differentiation of various types of stem cells. Exercise may improve organ regeneration and function. This review characterizes\\u000a different stem and progenitor cells and their sources and summarizes mechanisms by which exercise contributes to stem-cell-induced\\u000a regeneration and adaptation in different tissues. The

Patrick Wahl; Wilhelm Bloch

269

Identification of Clonogenic Common Lymphoid Progenitors in Mouse Bone Marrow  

Microsoft Academic Search

The existence of a common lymphoid progenitor that can only give rise to T cells, B cells, and natural killer (NK) cells remains controversial and constitutes an important gap in the hematopoietic lineage maps. Here, we report that the Lin?IL-7R+Thy-1?Sca-1loc-Kitlo population from adult mouse bone marrow possessed a rapid lymphoid-restricted (T, B, and NK) reconstitution capacity in vivo but completely

Motonari Kondo; Irving L. Weissman; Koichi Akashi

1997-01-01

270

Effect of Reishi polysaccharides on human stem\\/progenitor cells  

Microsoft Academic Search

The polysaccharide fraction of Ganoderma lucidum (F3) was found to benefit our health in many ways by influencing the activity of tissue stem\\/progenitor cells. In this study, F3 was found to promote the adipose tissue MSCs’ aggregation and chondrosphere formation, with the increase of CAM (N-CAM, I-CAM) expressions and autokine (BMP-2, IL-11, and aggrecan) secretions, in an in vitro chondrogenesis

Wan-Yu Chen; Wen-Bin Yang; Chi-Huey Wong; Daniel Tzu-Bi Shih

2010-01-01

271

Ginsenoside Rg1 promotes endothelial progenitor cell migration and proliferation  

Microsoft Academic Search

Aim:To investigate the effect of ginsenoside Rg1 on the migration, adhesion, proliferation, and VEGF expression of endothelial progenitor cells (EPCs).Methods:EPCs were isolated from human peripheral blood and incubated with different concentrations of ginsenoside Rg1 (0.1, 0.5, 1.0, and 5.0 ?mol\\/L) and vehicle controls. EPC migration was detected with a modified Boyden chamber assay. EPC adhesion was determined by counting adherent

Ai-wu Shi; Xiao-bin Wang; Feng-xiang Lu; Min-min Zhu; Xiang-qing Kong; Ke-jiang Cao

2009-01-01

272

Stem and progenitor cells in human umbilical cord blood  

Microsoft Academic Search

Both stem cells and progenitor cells are present in umbilical cord blood (UCB) at a high frequency, making these cells a major\\u000a target population for experimental and clinical studies. As the use of autologous or allogeneic hematopoietic stem cell transplantation\\u000a in the treatment of various diseases has grown rapidly in recent years, the concept of UCB banking for future use

Myoung Woo Lee; In Keun Jang; Keon Hee Yoo; Ki Woong Sung; Hong Hoe Koo

2010-01-01

273

Characterization of Wheat GlutenCharacterization of Wheat Gluten Proteins by HPLC and MALDIProteins by HPLC and MALDI  

E-print Network

Characterization of Wheat GlutenCharacterization of Wheat Gluten Proteins by HPLC and MALDIProteins/or classification of commercial wheat samples. 2. The procedure characterizes gluten proteins of Teal and Durum sequencing with MS/MS. 3. Among gluten proteins that have been identified are glutenin high molecular weight

Ens, Werner

274

Tolerance to Imidazolinone Herbicides in Wheat  

PubMed Central

An imidazolinone-tolerant wheat (Triticum aestivum L. em Thell) mutant in the winter wheat cultivar Fidel has been identified and characterized. The mutant was isolated from a population derived through seed mutagenesis of the variety with an aqueous solution containing sodium azide. Imidazolinone-tolerant wheat seedlings were selected from the M2 generation of the population in the presence of imazethapyr herbicide and identified as herbicide-insensitive individuals. The trait is inherited as a single semidominant gene and confers high levels of tolerance to imazethapyr. Acetohydroxyacid synthase activity in extracts from imidazolinonetolerant plants was less inhibited by imazethapyr than the enzyme from the wild type. The herbicide-tolerant plants have a completely normal phenotype and display no negative effects on growth and yield in either the absence or presence of imazethapyr. PMID:16653071

Newhouse, Keith E.; Smith, Wendy A.; Starrett, Mark A.; Schaefer, Thomas J.; Singh, Bijay K.

1992-01-01

275

Wheat productivity estimates using LANDSAT data  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. Objective measurements of percent green wheat cover on May 21 were significantly correlated with yield, as were measurements of green LAI and LANDSAT data. Three data sets from the Finney test site were analyzed from LANDSAT passes on 22 November 1974, 15 April 1975, and 21 May 1975. After mean signal values in each band were computed for each sufficiently large wheat field, the mean values were correlated with the farmer estimates of wheat grain yield in order to assess relative information content. It is clear that the single best spectral temporal band for predicting yield is the 15 April red band (0.6-0.7 microns, band 5), with the 15 April green band (0.5-0.6 microns, band 4) a close second.

Nalepka, R. F.; Colwell, J. (principal investigators); Rice, D. P.

1976-01-01

276

A novel mastrevirus infecting wheat in India.  

PubMed

A new mastrevirus (family Geminivridae) infecting wheat in India was detected by rolling-circle amplification (RCA). The complete nucleotide sequence of the virus was determined to be 2783 bp long. Analysis of the nucleotide sequence revealed identity and a genome organisation typical of a mastrevirus. An identical virus was detected in the candidate insect vector (leafhopper) collected from the field. Agroinoculation of young wheat plants with an infectious clone of the virus resulted in dwarfing of plants, identical to what was observed in the field, confirming that this novel virus was the causative agent of the disease. Considering the low degree of sequence identity to any known mastrevirus, the virus described here is suggested to be a member of a new species. Based on symptoms, we propose the name "wheat dwarf India virus". PMID:22752839

Kumar, Jitendra; Singh, Sudhir P; Kumar, Jitesh; Tuli, Rakesh

2012-10-01

277

Improvement of megakaryocytic progenitor culture for toxicological investigations.  

PubMed

The aim of this work was to obtain an in vitro test for the evaluation of xenobiotic toxicity on the proliferation and on the differentiation of megakaryocyte progenitors. The rapid rate of blood cell renewal makes the hematopoietic system a susceptible target for xenobiotic toxicity. Hematotoxic molecules can affect one or more hematopoietic lineages leading to blood disorders. Megakaryocytopoiesis in vitro models applied to toxicological investigations needs to be accurate, precise, reproducible, sensitive and specific. Human hematopoietic progenitors from umbilical cord blood were seeded in a collagen medium. Three solvents have been selected (ethanol, methanol, acetone), and one (dimethyl sulfoxide; DMSO) has been eliminated due to its cytotoxicity at tested concentrations. Cryopreservation did not affect the sensitivity of CFU-MK to xenobiotics. An overnight incubation of cell suspensions as cell suspension enrichment before plating gave better cloning efficiency than CD34(+) cells negative selection. Comparison between different parameters allowed us to propose a protocol suitable for an in vitro megakaryocytopoiesis model in toxicological investigations. The effects of three toxins were studied on CFU-MK development in order to verify the efficiency of this clonogenic assays for toxicity testing. The CFU-MK culture conditions defined revealed their usefulness for investigating drug cytoxicity towards megakaryocytic progenitors and disturbance of their proliferation. PMID:11698171

Froquet, R; Sibiril, Y; Parent-Massin, D

2001-12-01

278

Where do the progenitors of millisecond pulsars come from?  

NASA Astrophysics Data System (ADS)

Observations of a large population of millisecond pulsars (MSPs) show a wide divergence in the orbital periods (from approximately hours to a few months). In the standard view, low-mass X-ray binaries (LMXBs) are considered as progenitors for some MSPs during the recycling process. We present a systematic study that combines different types of compact objects in binaries such as cataclysmic variables (CVs), LMXBs, and MSPs. We plot them together in the so called Corbet diagram. Larger and different samples are needed to better constrain the result as a function of the environment and formations. A scale diagram showing the distribution of MSPs for different orbital periods and the aspects for their progenitors relying on accretion induced collapse (AIC) of white dwarfs in binaries. Thus massive CVs (M ? 1.1 M?) can play a vital role on binary evolution, as well as of the physical processes involved in the formation and evolution of neutron stars and their magnetic fields, and could turn into binary MSPs with different scales of orbital periods; this effect can be explained by the AIC process. This scenario also suggests that some fraction of isolated MSPs in the Galactic disk could be formed through the same channel, forming the contribution of some CVs to the single-degenerate progenitors of Type Ia supernova. Furthermore, we have refined the statistical distribution and evolution by using updated data. This implies that the significant studies of compact objects in binary systems can benefit from the Corbet diagram.

Taani, A.; Zhang, C. M.; Al-Wardat, M.; Zhao, Y. H.

2012-01-01

279

Defining skeletal muscle resident progenitors and their cell fate potentials.  

PubMed

The satellite cell is the major tissue-resident stem cell underlying muscle regeneration; however, multiple non-satellite myogenic progenitors as well as non-myogenic populations that support the muscle regenerative process have been identified. PW1 is expressed in satellite cells as well as in a subset of interstitial cells with myogenic potential termed PICs (PW1+ interstitial cells). Microarray profiling revealed that PICs express a broad range of genes common to mesenchymal stem cells, whereas satellite cells express genes consistent with a committed myogenic progenitor. Isolated PICs from both young and adult muscles can differentiate into smooth and skeletal muscle and fat whereas satellite cells are restricted to a skeletal muscle fate. We demonstrate that the adipogenic potential of PICs corresponds to a subpopulation that expresses platelet derived growth factor receptor alpha (PDGFR?) and overlaps with the recently described interstitial adipogenic progenitors. By contrast, PICs with myogenic potential do not express PDGFR?. Moreover, we observe a discrete and transient population of juvenile PICs based upon SCA1 expression that disappears by 3 weeks of postnatal development coincident with a switch in the cellular and genetic mechanisms underlying postnatal muscle growth. PMID:23739133

Pannérec, Alice; Formicola, Luigi; Besson, Vanessa; Marazzi, Giovanna; Sassoon, David A

2013-07-01

280

Regeneration of Glomerular Podocytes by Human Renal Progenitors  

PubMed Central

Depletion of podocytes, common to glomerular diseases in general, plays a role in the pathogenesis of glomerulosclerosis. Whether podocyte injury in adulthood can be repaired has not been established. Here, we demonstrate that in the adult human kidney, CD133+CD24+ cells consist of a hierarchical population of progenitors that are arranged in a precise sequence within Bowman's capsule and exhibit heterogeneous potential for differentiation and regeneration. Cells localized to the urinary pole that expressed CD133 and CD24, but not podocyte markers (CD133+CD24+PDX? cells), could regenerate both tubular cells and podocytes. In contrast, cells localized between the urinary pole and vascular pole that expressed both progenitor and podocytes markers (CD133+CD24+PDX+) could regenerate only podocytes. Finally, cells localized to the vascular pole did not exhibit progenitor markers, but displayed phenotypic features of differentiated podocytes (CD133?CD24?PDX+ cells). Injection of CD133+CD24+PDX? cells, but not CD133+CD24+PDX+ or CD133-CD24? cells, into mice with adriamycin-induced nephropathy reduced proteinuria and improved chronic glomerular damage, suggesting that CD133+CD24+PDX? cells could potentially treat glomerular disorders characterized by podocyte injury, proteinuria, and progressive glomerulosclerosis. PMID:19092120

Ronconi, Elisa; Sagrinati, Costanza; Angelotti, Maria Lucia; Lazzeri, Elena; Mazzinghi, Benedetta; Ballerini, Lara; Parente, Eliana; Becherucci, Francesca; Gacci, Mauro; Carini, Marco; Maggi, Enrico; Serio, Mario; Vannelli, Gabriella Barbara; Lasagni, Laura; Romagnani, Sergio; Romagnani, Paola

2009-01-01

281

Decoding the stellar fossils of the dusty Milky Way progenitors  

E-print Network

We investigate the metallicity distribution function (MDF) in the Galactic halo and the relative fraction of Carbon-normal and Carbon-rich stars. To this aim, we use an improved version of the semi-analytical code GAlaxy MErger Tree and Evolution (GAMETE), that reconstructs the hierarchical merger tree of the MW, following the star formation history and the metal and dust evolution in individual progenitors. The predicted scaling relations between the dust, metal and gas masses for MW progenitors show a good agreement with observational data of local galaxies and of Gamma Ray Burst (GRB) host galaxies at 0.1 140 M_{sun}, into the Pair-Instability SN progenitor mass range. The relative contribution of C-normal and C-enhanced stars to the MDF and its dependence on [Fe/H] points to a scenario where the Pop III/II transition is driven by dust-cooling and the first low-mass stars form when the dust-to-gas ratio in their parent clouds exceeds a critical value of D_crit = 4.4 x 10^{-9}.

de Bennassuti, Matteo; Valiante, Rosa; Salvadori, Stefania

2014-01-01

282

Identifying Supernova Progenitors and Constraining the Explosion Channels  

NASA Astrophysics Data System (ADS)

Connecting the endpoints of massive star evolution with the various types of core-collapse supernovae (SNe) is ultimately the fundamental puzzle to be explored and solved. We can assemble clues indirectly, e.g., from information about the environments in which stars explode and establish constraints on the evolutionary phases of these stars. However, this is best accomplished through direct identification of the actual star that has exploded in pre-supernova imaging, preferably in more than one photometric band, where color and luminosity for the star can be precisely measured. We can then interpret the star's properties in light of expectations from the latest massive stellar evolutionary models, to attempt to assign an initial mass to the progenitor. So far, this has been done most successfully for SNe II-P, for which we now know that red supergiants in a relatively limited initial mass range are responsible. More recently, we have limited examples of the progenitors of SNe II-L, IIn, and IIb. The progenitors of SNe Ib and Ic, however, have been elusive so far; I will discuss the current status of our knowledge of this particular channel.

Van Dyk, Schuyler D.

2012-09-01

283

Cartilage repair in vivo: the role of migratory progenitor cells.  

PubMed

The most common diseases of the joints and its tissues are osteoarthritis and rheumatoid arthritis, with osteoarthritis being anticipated to be the fourth leading cause of disability by the year 2020. To date, no truly causal therapies are available, and this has promoted tissue engineering attempts mainly involving mesenchymal stem cells. The goal of all tissue repairs would be to restore a fully functional tissue, here a hyaline articular cartilage. The hyaline cartilage is the most affected in osteoarthritis, where altered cell-matrix interactions gradually destroy tissue integrity. In rheumatoid arthritis, the inflammatory aspect is more important, and the cartilage tissue is destroyed by the invasion of tumor-like pannus tissue arising from the inflamed synovia. Furthermore, the fibrocartilage of the meniscus is clearly involved in the initiation of osteoarthritis, especially after trauma. Recent investigations have highlighted the role of migratory progenitor cells found in diseased tissues in situ. In osteoarthritis and rheumatoid arthritis, these chondrogenic progenitor cells are involved in regeneration efforts that are largely unsuccessful in diseased cartilage tissue. However, these progenitor cells are interesting targets for a cell-based regenerative therapy for joint diseases. PMID:25240685

Schminke, Boris; Miosge, Nicolai

2014-11-01

284

Possibility of mixed progenitor cells in sea star arm regeneration.  

PubMed

In contrast to most vertebrates, invertebrate deuterostome echinoderms, such as the sea star Asterias rubens, undergo regeneration of lost body parts. The current hypothesis suggests that differentiated cells are the main source for regenerating arm in sea stars, but there is little information regarding the origin and identity of these cells. Here, we show that several organs distant to the regenerating arm responded by proliferation, most significantly in the coelomic epithelium and larger cells of the pyloric caeca. Analyzing markers for proliferating cells and parameters indicating cell ageing, such as levels of DNA damage, pigment, and lipofuscin contents as well as telomere length and telomerase activity, we suggest that cells contributing to the new arm likely originate from progenitors rather than differentiated cells. This is the first study showing that cells of mixed origin may be recruited from more distant sources of stem/progenitor cells in a sea star, and the first described indication of a role for pyloric caeca in arm regeneration. Data on growth rate during arm regeneration further indicate that regeneration is at the expense of whole animal growth. We propose a new working hypothesis for arm regeneration in sea stars involving four phases: wound healing by coelomocytes, migration of distant progenitor cells of mixed origin including from pyloric caeca, proliferation in these organs to compensate for cell loss, and finally, local proliferation in the regenerating arm. PMID:20700890

Hernroth, Bodil; Farahani, Farhad; Brunborg, Gunnar; Dupont, Sam; Dejmek, Annika; Sköld, Helen Nilsson

2010-09-15

285

Response of wheat to sulfur fertilization  

SciTech Connect

Coker 747/sup 3/ wheat (Triticum aestivum L.) was grown on Keo silt loam (coarse-silty, mixed, thermic Dystric Fluventic Entrochrepts) with four S sources applied at various rates for two years. The innate S level of this soil was not adequate for optimum grain yield; therefore, additional S significantly increased grain yield and S concentration and decreased N/S ratios in wheat tissue. Minimum S concentration and N/S ratios in plant tissue for maximum yield ranged from 1.3 to 2.73 g S/kg and 9.5 to 19.2, respectively.

Mahler, R.J.; Maples, R.L.

1986-01-01

286

Wheat Versus Milo for Dairy Cows.  

E-print Network

BULLE -, -1' CAA~ AGRICULTURAL ciiPERIMER~5dTFl A. B. CONNOR, DIRECTOR COLLEGE STATION, BRAZOS COUNTY, TEXAS DIVISION OF DAIRY HUSBANDRY Wheat Versus Milo For Dairy Cows IT, 1933 4ND ME , 0. WAI ZAL COLLEGE 0 resident IF TEXA STATION...BULLE -, -1' CAA~ AGRICULTURAL ciiPERIMER~5dTFl A. B. CONNOR, DIRECTOR COLLEGE STATION, BRAZOS COUNTY, TEXAS DIVISION OF DAIRY HUSBANDRY Wheat Versus Milo For Dairy Cows IT, 1933 4ND ME , 0. WAI ZAL COLLEGE 0 resident IF TEXA STATION...

Copeland, O. C. (Orlin Cephas)

1933-01-01

287

Pre-Harvest Sprouting in Wheat  

E-print Network

E-336 1/05 Gaylon Morgan, State Extension Small Grains Specialist Texas A&M University, College Station, Texas P re-Harvest Wheat has a minimal seed-dormancy mecha- nism, which can lead to seed sprouting prior to har- vest (pre-harvest sprouting... conditions prior to harvest, (2) temperatures during such wet weather, (3) the growth stage of ripening grain, and (4) the inherent dormancy level attributable to a variety?s genetics. Germination begins as a wheat kernel absorbs moisture and swells...

Morgan, Gaylon

2005-01-26

288

Effects of herbicide applications in wheat fields  

PubMed Central

The present review encompasses the physiological and yield constraints of herbicide applications with special reference to wheat productivity. Post-independence lagging of Indian agriculture to feed its population led to haphazard use of chemical pesticides and weedicides which deteriorated the productivity pay-off particularly of wheat and rice. Past some decades witnessed the potential use of certain phytohormones in augmenting abiotic stress to get rid of yield gap and productivity constraints. We summed up with reviewing the potential role of these natural regulators in overcoming above mentioned drawbacks to substitute or to integrate these chemicals with the use of plant hormones. PMID:22516826

Varshney, Sugandha; Hayat, Shamshul; Alyemeni, Mohammed Nasser; Ahmad, Aqil

2012-01-01

289

The Ph1 Locus Suppresses Cdk2-Type Activity during Premeiosis and Meiosis in Wheat W OA  

E-print Network

of related (homoeologous) chromosomes, hexaploid wheat (Triticum aestivum) restricts pairing to just true in hexaploid wheat (Triticum aestivum) and tetraploid wheat (Triticum turgidum) is under the genetic control

Shaw, Peter

290

Mesenchymal stem/progenitor cell isolation from tooth extraction sockets.  

PubMed

Bone marrow-derived mesenchymal stem/progenitor cells (BMSCs) are commonly used in regeneration therapy. The current primary source of BMSCs is the iliac crest; however, the procedure is associated with various burdens on the patient, including the risk of pain and infection. Hence, the possibility to collect BMSCs from other, more accessible, sources would be an attractive approach. It is well known that stem cells migrate from surrounding tissues and play important roles in wound healing. We thus hypothesized that stem/progenitor cells could be isolated from granulation tissue in the dental socket, and we subsequently collected granulation tissue from dog dental socket 3 d after tooth extraction. After enzyme digestion of the collected tissue, the cells forming colonies constituted the dental socket-derived stem/progenitor cells (dDSCs). Next, dDSCs were compared with dog BMSCs (dBMSCs) for phenotype characterization. A flow cytometric analysis showed that dDSCs were positive for CD44, CD90, and CD271 but negative for CD34 and CD45, similar to dBMSCs. dDSCs also exhibited osteogenic, adipogenic, and chondrogenic differentiation ability, similar to dBMSCs, with a higher capacity for colony formation, proliferation, and motility than dBMSCs. In addition, an in vivo ectopic bone formation assay showed that dDSCs and dBMSCs both induced hard tissue formation, although only dDSCs formed a fibrous tissue-like structure connected to the newly formed bone. Finally, we tested the ability of dDSCs to regenerate periodontal tissue in a one-wall defect model. The defects in the dDSC-transplanted group (?-TCP/PGA/dDSCs) were regenerated with cementum-like and periodontal ligament-like tissues and alveolar bone, whereas only bony tissue was observed in the control group (?-TCP/PGA). In conclusion, we identified and characterized a population of stem/progenitor cells in granulation tissue obtained from the dental socket that exhibited several characteristics similar to those of BMSCs. Dental sockets could therefore be a novel source for isolating stem/progenitor cells from bone. PMID:25170030

Nakajima, R; Ono, M; Hara, E S; Oida, Y; Shinkawa, S; Pham, H T; Akiyama, K; Sonoyama, W; Maekawa, K; Kuboki, T

2014-11-01

291

New approach to the fungal decontamination of wheat used for wheat sprouts: effects of aminolevulinic acid.  

PubMed

Nowadays, there is a growing interest in natural, minimally processed, nutritional and healthy foods. Sprouted seeds can be offered as natural nutritive products. Regrettably, existing seed decontamination technologies are limited and have specific disadvantages. 5-aminolevulinic acid (5-ALA) as a novel and effective tool for wheat decontamination from microfungi is proposed in this work. Inhibition of wheat with 5-ALA revealed a drastically suppressed development of microfungi. Studies of wheat germination characteristics showed that 5-ALA stimulates the growth of wheat seedlings and roots without impairing the vigor of germination and the viability of seeds. 5-ALA also induces either marginal or significant activities of antioxidant enzymes which can be associated with enhanced cellular capacity to detoxify reactive oxygen species. The results indicate that 5-ALA application may be an effective, environmentally friendly and inexpensive technology to be used in producing sprouts for human consumption. PMID:17350127

Luksiene, Zivile; Danilcenko, Honorata; Taraseviciene, Zivile; Anusevicius, Zilvinas; Maroziene, Audrone; Nivinskas, Henrikas

2007-05-01

292

Natural variation in grain composition of wheat and related cereals.  

PubMed

The wheat grain comprises three groups of major components, starch, protein, and cell wall polysaccharides (dietary fiber), and a range of minor components that may confer benefits to human health. Detailed analyses of dietary fiber and other bioactive components were carried out under the EU FP6 HEALTHGRAIN program on 150 bread wheat lines grown on a single site, 50 lines of other wheat species and other cereals grown on the same site, and 23-26 bread wheat lines grown in six environments. Principal component analysis allowed the 150 bread wheat lines to be classified on the basis of differences in their contents of bioactive components and wheat species (bread, durum, spelt, emmer, and einkorn wheats) to be clearly separated from related cereals (barley, rye, and oats). Such multivariate analyses could be used to define substantial equivalence when novel (including transgenic) cereals are considered. PMID:23414336

Shewry, Peter R; Hawkesford, Malcolm J; Piironen, Vieno; Lampi, Ann-Maija; Gebruers, Kurt; Boros, Danuta; Andersson, Annica A M; Åman, Per; Rakszegi, Mariann; Bedo, Zoltan; Ward, Jane L

2013-09-01

293

Fetal hepatic progenitors support long-term expansion of hematopoietic stem cells  

PubMed Central

We have developed a coculture system that establishes DLK+ fetal hepatic progenitors as the authentic supportive cells for expansion of hematopoietic stem (HSCs) and progenitor cells. In 1-week cultures supplemented with serum and supportive cytokines, both cocultured DLK+ fetal hepatic progenitors and their conditioned medium supported rapid expansion of hematopoietic progenitors and a small increase in HSC numbers. In 2- and 3-week cultures DLK+ cells, but not their conditioned medium, continuously and significantly (>20-fold) expanded both hematopoietic stem and progenitor cells. Physical contact between HSCs and DLK+ cells was crucial to maintaining this long-term expansion. Similar HSC expansion (approximately sevenfold) was achieved in cocultures using a serum-free, low cytokine-containing medium. In contrast, DLK? cells are incapable of expanding hematopoietic cells, demonstrating that hepatic progenitors are the principle supportive cells for HSC expansion in the fetal liver. PMID:23415675

Chou, Song; Flygare, Johan; Lodish, Harvey F.

2013-01-01

294

Rai is a new regulator of neural progenitor migration and glioblastoma invasion.  

PubMed

The invasive nature of glioblastoma (GBM) is one important reason for treatment failure. GBM stem/progenitor cells retain the migratory ability of normal neural stem/progenitor cells and infiltrate the brain parenchyma. Here, we identify Rai (ShcC/N-Shc), a member of the family of Shc-like adaptor proteins, as a new regulator of migration of normal and cancer stem/progenitor cells. Rai is expressed in neurogenic areas of the brain and its knockdown impairs progenitor migration to the olfactory bulb. Its expression is retained in GBM stem/progenitor cells where it exerts the same promigratory activity. Rai silencing in cancer stem/progenitor cells isolated from different patients causes significant decrease in cell migration and invasion, both in vitro and in vivo, providing survival benefit. Rai depletion is associated with alteration of multiple-signaling pathways, yet it always leads to reduced expression of proinvasive genes. PMID:22311806

Ortensi, Barbara; Osti, Daniela; Pellegatta, Serena; Pisati, Federica; Brescia, Paola; Fornasari, Lorenzo; Levi, Daniel; Gaetani, Paolo; Colombo, Piergiuseppe; Ferri, Anna; Nicolis, Silvia; Finocchiaro, Gaetano; Pelicci, Giuliana

2012-05-01

295

Two waves of distinct hematopoietic progenitor cells colonize the fetal thymus.  

PubMed

The generation of T cells depends on the migration of hematopoietic progenitor cells to the thymus throughout life. The identity of the thymus-settling progenitor cells has been a matter of considerable debate. Here we found that thymopoiesis was initiated by a first wave of T cell lineage-restricted progenitor cells with limited capacity for population expansion but accelerated differentiation into mature T cells. They gave rise to ?? and ?? T cells that constituted V?3(+) dendritic epithelial T cells. Thymopoiesis was subsequently maintained by less-differentiated progenitor cells that retained the potential to develop into B cells and myeloid cells. In that second wave, which started before birth, progenitor cells had high proliferative capacity but delayed differentiation capacity and no longer gave rise to embryonic ?? T cells. Our work reconciles conflicting hypotheses on the nature of thymus-settling progenitor cells. PMID:24317038

Ramond, Cyrille; Berthault, Claire; Burlen-Defranoux, Odile; de Sousa, Ana Pereira; Guy-Grand, Delphine; Vieira, Paulo; Pereira, Pablo; Cumano, Ana

2014-01-01

296

Efficient production of haploid wheat ( Triticum aestivum ) through crosses between Japanese wheat and maize ( Zea mays )  

Microsoft Academic Search

Four Japanese wheat varieties, three crossable and one non-crossable with Hordeum bulbosum, were pollinated with maize pollen of 5 genotypes. By the application of 2,4-dichlorophenoxyacetic acid after pollination, embryos kept developing on wheat plants until 14 days after pollination. The frequency of embryo formation was significantly different among the maize genotypes, varying from 18.0% to 31.9%, but not among the

Kazuhiro Suenaga; Kousuke Nakajima

1989-01-01

297

[Disease index inversion of wheat stripe rust on different wheat varieties with hyperspectral remote sensing].  

PubMed

It is becoming more and more important to use mixed wheat varieties to control wheat stripe rust. Different wheat varieties were planted in field and stripe rust was caused by artificial inoculation. Disease index (DI) was assessed and the canopy reflection data of wheat canopy were obtained by ASD FieldSpec HandHeld FR(325-1 075 nm) made by ASD Company. The correlation analysis between DI and spectral data (reflectance and the first derivative) was conducted, and the estimation models between DI and reflection data (reflectance at 690 and 850 nm, SDr, NDVI and RVI) were built using linear regression method. The results showed that different combinations of wheat varieties had the similar variation at different disease index. DI has positive correlation with reflectance of wheat canopy in visible region, and has significant negative correlation in the near infrared region. DI has stable negative correlation with the first derivative in the region of 700-760 nm and with big fluctuation in other regions. The correlation was compared between DI and hyperspectral derivative index, and SDr has the best correlation with DI. DI estimation models were built based on the canopy reflectance at 690 and 850 nm, SDr, NDVI and RVI. The determinant coefficient of the models is between 0.588 and 0.855, 0.669 and 0.911, 0.534 and 0.773, and 0.587 and 0.751, respectively, and all the models were fit well. The results indicated that DI of wheat stripe rust could be inverted using hyperspectral remote sensing technique and that the inversion effect was hardly influenced by the different combinations of wheat varieties. PMID:20210168

Guo, Jie-Bin; Huang, Chong; Wang, Hai-Guang; Sun, Zhen-Yu; Ma, Zhan-Hong

2009-12-01

298

On-farm impacts of zero tillage wheat in South Asia's rice–wheat systems  

Microsoft Academic Search

The recent slow down in productivity growth in the irrigated areas of the Indo-Gangetic Plains of South Asia has led to a quest for resource-conserving technologies that can reduce production costs, save water and improve production. Findings from farm surveys are used to evaluate the on-farm impacts of zero tillage (ZT) wheat in the rice–wheat systems of India's Haryana state

Olaf Erenstein; Umar Farooq; R. K. Malik; Muhammad Sharif

2008-01-01

299

Composition and stability of anthocyanins in blue-grained wheat.  

PubMed

Wheat grain is recognized as a good source of potentially health-enhancing components such as dietary fiber, phenolics, tocopherols, and carotenoids. Anthocyanins, another group of bioactive compounds, are found in blue and purple wheat grains. In the present study, a blue aleurone spring wheat line "Purendo 38" with relatively high content of total anthocyanins was used to investigate the composition and stability of anthocyanins over three crop years. Commercial cultivars of purple (Konini) and red (Katepwa) wheats were included in the study. Separation of anthocyanins by high-performance liquid chromatography (HPLC) showed that each wheat had a distinct anthocyanin profile. Four major anthocyanins were separated from blue wheat extracts as compared to five anthocyanins in purple wheat. Cyanidin 3-glucoside was the predominant anthocyanin in purple wheat, whereas it was the second major anthocyanin in blue wheat. The predominant anthocyanin in blue wheat, making up approximately 41% of the total anthocyanin content, remains to be structurally unidentified. Blue wheat anthocyanins were thermally most stable at pH 1. Their degradation was slightly lower at pH 3 as compared to pH 5. Increasing the temperature from 65 to 95 degrees C increased degradation of blue wheat anthocyanins. Addition of SO(2) during heating of blue wheat had a stabilizing effect on anthocyanin pigments. The optimal SO(2) concentrations were 500-1000 ppm for whole meals and 1000-3000 ppm for isolated anthocyanins. Further studies are underway to identify and verify individual anthocyanins in blue wheat and their potential end uses. PMID:12670152

Abdel-Aal, El-Sayed M; Hucl, Pierre

2003-04-01

300

Cont. Rot. Rot. DC Cont. Rot. Rot. DC Cont. Rot. Rot. DC Corn Corn Beans Wheat Beans Corn Corn Beans Wheat Beans Corn Corn Beans Wheat Beans  

E-print Network

with a 90% germination rate. Double-crop soybeans are drilled with a seeding rate of 195,000 seeds per acreCont. Rot. Rot. DC Cont. Rot. Rot. DC Cont. Rot. Rot. DC Corn Corn Beans Wheat Beans Corn Corn Beans Wheat Beans Corn Corn Beans Wheat Beans Expected yield per acre2 118 126 39 62 23 149 158 49 70 29

Jackson, Scott A.

301

Isolation and characterization of porcine adult muscle-derived progenitor cells  

Microsoft Academic Search

Here, we report the isolation of progenitor cells from pig skeletal muscle tissue fragments. Muscle progenitor cells were stimulated to migrate from protease-digested tissue fragments and cultured in the presence of 5 ng\\/ml basic fibroblast growth factor. The cells showed a sustained long-term expansion capacity (>120 population doublings) while maintaining a normal karyotype. The proliferating progenitor cells expressed PAX3, DESMIN,

Karlijn J. Wilschut; Sridevi Jaksani; Juliette Van Den Dolder; Henk P. Haagsman; Bernard A. J. Roelen

2008-01-01

302

Improving yield and quality traits of durum wheat by introgressing chromosome segments from hexaploid wheat.  

PubMed

Durum wheat (Triticum turgidum durum; 2n = 4x = 28; genome AABB) has long been an important food resource for human diets. The projected increase of the world's population to 9.1 billion by 2050 has highlighted the importance and urgency for improving the yield and quality performance of durum wheat. A backcrossed population, which was derived from the durum wheat variety 'Bellaroi' (recurrent parent) and the hexaploid genotype 'CSCR6' (donor parent), was used to investigate the feasibility of improving yield- and quality-related traits of durum wheat by introgressing chromosome fragments from hexaploid wheat. The population means for grain protein content, gluten content, spike length, and spikelet number were improved compared with those of the recurrent parent 'Bellaroi'. A small proportion of the backcross population lines showed significant improvements in spike length and spikelet number compared with the recurrent parent 'Bellaroi'. Some loci with significant effects for plant height, spike length, spikelet number, and thousand-grain weight were identified. Several of these loci affected more than one trait. These results showed that the introgression of chromosome fragments from 'CSCR6' into the durum genetic background could be an effective method for improving yield and quality traits of durum wheat. In addition, the loci showing significant effects on desired traits in this study could be fine mapped using an F2 population obtained by backcrossing the lines that carry the positive allele(s) with the recurrent parent. PMID:24338405

Ma, J; Zhang, C Y; Yan, G J; Liu, C J

2013-01-01

303

Reproduction and development of Russian wheat aphid biotype 2 on crested wheatgrass, intermediate wheatgrass, and susceptible and resistant wheat.  

PubMed

The Russian wheat aphid, Diuraphis noxia (Kurdjumov), is an economically important pest of small grains. Since its introduction into North America in 2003, Russian wheat aphid Biotype 2 has been found to be virulent to all commercially available winter wheat, Triticum aestivum L., cultivars. Our goal was to examine differences in Russian wheat aphid reproduction and development on a variety of plant hosts to gain information about 1) potential alternate host refuges, 2) selective host pressures on Russian wheat aphid genetic variation, and 3) general population dynamics of Russian wheat aphid Biotype 2. We studied host quality of two wheatgrasses (crested wheatgrass, Agropyron cristatum [L.] Gaertn., and intermediate wheatgrass, Agropyron intermedium [Host] Beauvoir) and two types of winter wheat (T. aestivum, one Biotype 2 susceptible wheat, 'Custer' and one biotype 2 resistant wheat, STARS02RWA2414-11). The susceptible wheat had the highest intrinsic rate of increase, greatest longevity and greatest fecundity of the four host studied. Crested wheatgrass and the resistant wheat showed similar growth rates. Intermediate wheatgrass had the lowest intrinsic rate of increase and lowest fecundity of all tested hosts. PMID:18459422

Merrill, Scott C; Peairs, Frank B; Miller, Hayley R; Randolph, Terri L; Rudolph, Jeff B; Talmich, Emili E

2008-04-01

304

Molecular characterization of wheat polyphenol oxidase (PPO)  

Microsoft Academic Search

It is well-established that the enzyme polyphenol oxidase (PPO) is involved in undesirable browning of noodles, chapattis, middle east flat breads and steamed breads. Methods for measuring PPO activity have been developed, and the variation of PPO activity among wheat (Triticum aestivum L.) cultivars has been well documented. However, there is no report on the identification and characterization of a

T. Demeke; C. Morris

2002-01-01

305

Rheological properties of wheat flour doughs  

Microsoft Academic Search

Summary A comparative study was made of the large deformation and rupture properties of doughs from a medium strength and a weak wheat flour. Experiments were made by stretching, at a uniform rate, dough rings immersed in a liquid of matching density to prevent the rings from deforming under their own weight. Data were obtained on doughs differing in water

N. W. Tschoegl; J. A. Rinde; T. L. Smith

1970-01-01

306

Wheat Proteins Improve Cryopreservation of Rat Hepatocytes  

E-print Network

ARTICLE Wheat Proteins Improve Cryopreservation of Rat Hepatocytes Me´lanie Grondin, Francine Hamel.1002/bit.22270 ABSTRACT: Hepatocytes are an important physiological model for in vitro studies of drug metabolism and toxicity. However, fresh hepatocytes are not always available and hence cyopreservation

Sarhan, Fathey

307

Disulphide Bonds in Wheat Gluten Proteins  

Microsoft Academic Search

Disulphide bonds play a key role in determining the structure and properties of wheat gluten proteins. Comparison of the sequences of monomeric gliadins and polymeric glutenin subunits allows the identification of conserved and variant cysteine residues. Direct disulphide bond determination demonstrates that the conserved cysteine residues present in S-rich prolamins (?-type gliadins, ?-type gliadins and LMW subunits) form intra-chain disulphide

P. R. Shewry; A. S. Tatham

1997-01-01

308

Genetic transformation of wheat via particle bombardment.  

PubMed

Since its first invention in the late 1980s the particle gun has evolved from a basic gunpowder driven machine firing tungsten particles to one more refined which uses helium gas as the propellant to launch alternative heavy metal particles such as gold and silver. The simple principle is that DNA-coated microscopic particles (microcarriers) are accelerated at high speed by helium gas within a vacuum and travel at such a velocity as to penetrate target cells. However, the process itself involves a range of parameters which are open to variation: microparticle type and size, gun settings (rupture pressure, target distance, vacuum drawn, etc.), preparation of components (e.g., gold coating), and preparation of plant tissues. Here is presented a method optimized for transformation of wheat immature embryos using the Bio-Rad PDS-1000/He particle gun to deliver gold particles coated with a gene of interest and the selectable marker gene bar at 650 psi rupture pressure. Following bombardment, various tissue culture phases are used to encourage embryogenic callus formation and regeneration of plantlets and subsequent selection using glufosinate ammonium causes suppression of non-transformed tissues, thus assisting the detection of transformed plants. This protocol has been used successfully to generate transgenic plants for a wide range of wheat varieties, both spring and winter bread wheats (T. aestivum L.) and durum wheats (T. turgidum L.). PMID:24243206

Sparks, Caroline A; Jones, Huw D

2014-01-01

309

Disease Update in Wheat Gaylon Morgan  

E-print Network

There are three major foliar leaf diseases that commonly occur in Texas wheat fields, including Leaf Rust, Stripe Rust, and Powdery Mildew. On any given year, some regions of the state will usually have economically damaging levels of one or more of these diseases. In most years, significant Leaf Rust or Stripe Rust can

Mukhtar, Saqib

310

Transgenic wheat plants: a powerful breeding source  

Microsoft Academic Search

Plant breeders are always interested in new genetic resources. In thepast, the sources have been limited to existing germplasm. Geneticengineering now provides the opportunity for almost unlimited strategies tocreate novel resources. As a first stage, the Applied Biotechnology Center(ABC) at CIMMYT developed a method for the mass production of fertiletransgenic wheat (Triticum aestivum L.) that yields plants ready fortransfer to

A. Pellegrineschi; S. McLean; M. Salgado; L. Velazquez; R. Hernandez; R. M. Brito; M. Noguera; A. Medhurst; D. Hoisington

2001-01-01

311

Flowering time control in European winter wheat  

PubMed Central

Flowering time is an important trait in wheat breeding as it affects adaptation and yield potential. The aim of this study was to investigate the genetic architecture of flowering time in European winter bread wheat cultivars. To this end a population of 410 winter wheat varieties was evaluated in multi-location field trials and genotyped by a genotyping-by-sequencing approach and candidate gene markers. Our analyses revealed that the photoperiod regulator Ppd-D1 is the major factor affecting flowering time in this germplasm set, explaining 58% of the genotypic variance. Copy number variation at the Ppd-B1 locus was present but explains only 3.2% and thus a comparably small proportion of genotypic variance. By contrast, the plant height loci Rht-B1 and Rht-D1 had no effect on flowering time. The genome-wide scan identified six QTL which each explain only a small proportion of genotypic variance and in addition we identified a number of epistatic QTL, also with small effects. Taken together, our results show that flowering time in European winter bread wheat cultivars is mainly controlled by Ppd-D1 while the fine tuning to local climatic conditions is achieved through Ppd-B1 copy number variation and a larger number of QTL with small effects.

Langer, Simon M.; Longin, C. Friedrich H.; Wurschum, Tobias

2014-01-01

312

Efflux Of Nitrate From Hydroponically Grown Wheat  

NASA Technical Reports Server (NTRS)

Report describes experiments to measure influx, and efflux of nitrate from hydroponically grown wheat seedlings. Ratio between efflux and influx greater in darkness than in light; increased with concentration of nitrate in nutrient solution. On basis of experiments, authors suggest nutrient solution optimized at lowest possible concentration of nitrate.

Huffaker, R. C.; Aslam, M.; Ward, M. R.

1992-01-01

313

Hdac3 Is A Critical Regulator Of Neural Crest Progenitor Cell Biology.  

E-print Network

??Vertebrate embryogenesis relies on the coordinated development of multiple progenitor cell pools. Specific transcriptional programs regulate the specification, expansion, migration and eventual differentiation of these… (more)

Singh, Nikhil

2012-01-01

314

The disappearance of the progenitors of supernovae 1993J and 2003gd.  

PubMed

Using images from the Hubble Space Telescope and the Gemini Telescope, we confirmed the disappearance of the progenitors of two type II supernovae (SNe) and evaluated the presence of other stars associated with them. We found that the progenitor of SN 2003gd, an M-supergiant star, is no longer observed at the SN location and determined its intrinsic brightness using image subtraction techniques. The progenitor of SN 1993J, a K-supergiant star, is also no longer present, but its B-supergiant binary companion is still observed. The disappearance of the progenitors confirms that these two supernovae were produced by red supergiants. PMID:19299586

Maund, Justyn R; Smartt, Stephen J

2009-04-24

315

Role of membrane-type 1 matrix metalloproteinase in hematopoietic stem/progenitor cell trafficking.  

E-print Network

??Hematopoietic stem/progenitor cells (HSPC) are routinely used for transplantation to restore hematopoietic function; however, the molecular mechanisms governing their trafficking are not completely understood. Soluble… (more)

Shirvaikar, Neeta Chandan

2010-01-01

316

Endogenous Neural Progenitor Cells as Therapeutic Target After Spinal Cord Injury  

NSDL National Science Digital Library

Growing knowledge about the role of neural progenitor cells supports the hope that stem cell-based therapeutic approaches aimed at restoring function in the lesioned central nervous system can be established. Possible therapies for promoting recovery after spinal cord injury include stimulating the formation of neurons and glial cells by endogenous progenitor cells. This article reviews the current knowledge about the nature of adult progenitor cells in the intact and injured spinal cord and summarizes possibilities and limitations of cellular replacement strategies based on manipulations of endogenous spinal cord progenitor cells and their environment.

Franz-Josef Obermair (University of Zurich Neuromorphology); Aileen Schroter (University of Zurich Neuromorphology); Michaela Thallmair (University of Zurich Neuromorphology)

2008-10-18

317

Partial characterization of glutathione S-transferases from wheat (Triticum spp.) and purification of a safener-induced glutathione S-transferase from Triticum tauschii.  

PubMed Central

Hexaploid wheat (Triticum aestivum L.) has very low constitutive glutathione S-transferase (GST) activity when assayed with the chloroacetamide herbicide dimethenamid as a substrate, which may account for its low tolerance to dimethenamid in the field. Treatment of seeds with the herbicide safener fluxofenim increased the total GST activity extracted from T. aestivum shoots 9-fold when assayed with dimethenamid as a substrate, but had no effect on glutathione levels. Total GST activity in crude protein extracts from T. aestivum, Triticum durum, and Triticum tauschii was separated into several component GST activities by anion-exchange fast-protein liquid chromatography. These activities (isozymes) differed with respect to their activities toward dimethenamid or 1-chloro-2,4-dinitrobenzene as substrates and in their levels of induction by safener treatment. A safener-induced GST isozyme was subsequently purified by anion-exchange and affinity chromatography from etiolated shoots of the diploid wheat species T. tauschii (a progenitor of hexaploid wheat) treated with the herbicide safener cloquintocet-mexyl. The isozyme bound to a dimethenamid-affinity column and had a subunit molecular mass of 26 kD based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified enzyme (designated GST TSI-1) was recognized by an antiserum raised against a mixture of maize (Zea mays) GSTs. Amino acid sequences obtained from protease-digested GST TSI-1 had significant homology with the safener-inducible maize GST V and two auxin-regulated tobacco (Nicotiana tabacum) GST isozymes. PMID:9276955

Riechers, D E; Irzyk, G P; Jones, S S; Fuerst, E P

1997-01-01

318

Molecular features of adult mouse small intestinal epithelial progenitors  

PubMed Central

The adult mouse small intestinal epithelium undergoes perpetual regeneration, fueled by a population of multipotential stem cells and oligopotential daughters located at the base of crypts of Lieberkühn. Although the morphologic features of small intestinal epithelial progenitors (SiEPs) are known, their molecular features are poorly defined. Previous impediments to purification and molecular characterization of SiEPs include lack of ex vivo clonigenic assays and the difficulty of physically retrieving them from their niche where they are interspersed between their numerous differentiated Paneth cell daughters. To overcome these obstacles, we used germ-free transgenic mice lacking Paneth cells to obtain a consolidated population of SiEPs with normal proliferative activity. These cells were harvested by laser capture microdissection. Functional genomics analysis identified 163 transcripts enriched in SiEPs compared with Paneth cell-dominated normal crypt base epithelium. The dataset was validated by (i) correlation with the organellar composition of SiEPs versus Paneth cells, (ii) similarities to databases generated from recent mouse hematopoietic and neural stem cell genome anatomy projects, and (iii) laser capture microdissection/real-time quantitative RT-PCR studies of progenitor cell-containing populations retrieved from the small intestines, colons, and stomachs of conventionally raised mice. The SiEP profile has prominent representation of genes involved in c-myc signaling and in the processing, localization, and translation of mRNAs. This dataset, together with our recent analysis of gene expression in the gastric stem cell niche, discloses a set of molecular features shared by adult mouse gut epithelial progenitors. PMID:12552106

Stappenbeck, Thaddeus S.; Mills, Jason C.; Gordon, Jeffrey I.

2003-01-01

319

Molecular features of adult mouse small intestinal epithelial progenitors.  

PubMed

The adult mouse small intestinal epithelium undergoes perpetual regeneration, fueled by a population of multipotential stem cells and oligopotential daughters located at the base of crypts of Lieberkühn. Although the morphologic features of small intestinal epithelial progenitors (SiEPs) are known, their molecular features are poorly defined. Previous impediments to purification and molecular characterization of SiEPs include lack of ex vivo clonigenic assays and the difficulty of physically retrieving them from their niche where they are interspersed between their numerous differentiated Paneth cell daughters. To overcome these obstacles, we used germ-free transgenic mice lacking Paneth cells to obtain a consolidated population of SiEPs with normal proliferative activity. These cells were harvested by laser capture microdissection. Functional genomics analysis identified 163 transcripts enriched in SiEPs compared with Paneth cell-dominated normal crypt base epithelium. The dataset was validated by (i) correlation with the organellar composition of SiEPs versus Paneth cells, (ii) similarities to databases generated from recent mouse hematopoietic and neural stem cell genome anatomy projects, and (iii) laser capture microdissectionreal-time quantitative RT-PCR studies of progenitor cell-containing populations retrieved from the small intestines, colons, and stomachs of conventionally raised mice. The SiEP profile has prominent representation of genes involved in c-myc signaling and in the processing, localization, and translation of mRNAs. This dataset, together with our recent analysis of gene expression in the gastric stem cell niche, discloses a set of molecular features shared by adult mouse gut epithelial progenitors. PMID:12552106

Stappenbeck, Thaddeus S; Mills, Jason C; Gordon, Jeffrey I

2003-02-01

320

[The role of endothelial progenitor cells in renal disease].  

PubMed

Recent evidence suggests that injury to the renal vasculature may play an important role in the pathogenesis of both chronic and acute ischemic kidney injury. Early alterations in peritubular capillary blood flow during reperfusion have been documented and associated with loss of normal endothelial cell function. In addition, ischemia induces alterations in endothelial cells that may promote inflammation and procoagulant activity, thus contributing to vascular congestion. Reduction of the microvasculature density increases hypoxia-mediated fibrosis and alters proper hemodynamics, which may lead to hypertension. This may play a critical role in the progression of chronic kidney disease following initial recovery from ischemia/reperfusion-induced acute kidney injury. The turnover and replacement of endothelial cells is therefore an important mechanism in the maintenance of vascular integrity also in the kidney. It is becoming clear that impaired vascular repair mechanisms as a result of a reduced number and/or impaired function of endothelial progenitor cells may contribute to renal disease. Moreover, investigators have begun to identify potential mechanisms responsible for the loss of function of endothelial progenitors in renal disease. In allografts, persistent injury results in excessive turnover of graft vascular endothelial cells. Moreover, chronic damage elicits a response that is associated with the recruitment of both leukocytes and endothelial progenitors, facilitating an overlapping process of inflammation and angiogenesis. In conclusion, angiogenesis and endothelial cell turnover play a pivotal role in renal disease and allograft rejection. Manipulation of these processes might have important implications for the development of novel therapeutic strategies in the near future. PMID:18828116

Lazzeri, E; Angelotti, M L; Ballerini, L; Becherucci, F; Mazzinghi, B; Parente, E; Ronconi, E; Sagrinati, C; Romagnani, P; Lasagni, L

2008-01-01

321

Isolation of progenitor cells from cord blood using adhesion matrices  

PubMed Central

The aim of this study was to develop optimal conditions for selective adhesion and isolation of mesenchymal progenitor cells (MPCs) from cord blood and to determine their potential for osteogenic differentiation. Mononuclear cells (MNCs) were isolated by Ficoll-Paque gradient and plated onto 48-well culture plates precoated with: human or bovine collagen type I, human collagen type IV, fibronectin or matrigel. Cultures were incubated in ?MEM containing fetal calf serum. Viability of the adherent cells was determined by alamarBlue® assay after 2, 3, and 4 weeks. After 4 weeks in culture, cells were typsinized and replated. Primary cultures were analyzed by histochemistry and third passage cells by FACS. Isolated fibroblast-like cells were cultured in the presence of osteogenic factors and differentiation determined by Alizarin Red S staining, RT-PCR and electron dispersive spectroscopy (EDS). MNCs adhered to all types of matrices with the greatest adhesion rates on fibronectin. These cells were CD45+, CD105+, CD14+, CD49a+, CD49f+, CD44+ and CD34?. The highest incidence of progenitor cells (PC) was observed on fibronectin and polystyrene. Passages were CD45?, CD14?, CD34? and weakly CD105+. Primary cultures expressed endothelial/macrophage RNA markers whether cultured on fibronectin or polystyrene and these markers decreased upon passage. The best osteogenic differentiation was observed in MPCs cultured in osteogenic medium containing vitamin D3 and FGF9. These cells expressed the bone-related mRNA, collagen type I, core binding factor I (Cbfa I), osteocalcin and osteopontin. EDS of deposits produced by these cells demonstrated a calcium/phosphate ratio parallel to hydroxyapatite. It was concluded that fibronectin increased adhesion rates and isolation potential of cord blood mesenchymal progenitor cells. PMID:19003027

Srouji, Samer; Livne, Erella

2007-01-01

322

Decoding the stellar fossils of the dusty Milky Way progenitors  

NASA Astrophysics Data System (ADS)

We investigate the metallicity distribution function (MDF) in the Galactic halo and the relative fraction of carbon-normal and carbon-rich stars. To this aim, we use an improved version of the semi-analytical code GAlaxy MErger Tree and Evolution (GAMETE), that reconstructs the hierarchical merger tree of the Milky Way (MW), following the star formation history and the metal and dust evolution in individual progenitors. The predicted scaling relations between the dust, metal and gas masses for MW progenitors show a good agreement with observational data of local galaxies and of gamma-ray burst (GRB) host galaxies at 0.1 < z < 6.3. Comparing the simulated and the observed MDF, we find that in order to predict the formation of hyper-iron-poor stars at [Fe/H] < -4, faint supernova (SN) explosions have to dominate the metal yields produced by Population III (Pop III) stars, disfavouring a Pop III initial mass function that extends to stellar masses >140 M?, into the Pair-Instability SN progenitor mass range. The relative contribution of C-normal and C-enhanced stars to the MDF and its dependence on [Fe/H] points to a scenario where the Pop III/II transition is driven by dust cooling, and the first low-mass stars form when the dust-to-gas ratio in their parent clouds exceeds a critical value of {\\cal D}_crit = 4.4 × 10^{-9}. Other transition criteria do not predict any C-normal stars below [Fe/H] < -4, at odds with observations.

de Bennassuti, Matteo; Schneider, Raffaella; Valiante, Rosa; Salvadori, Stefania

2014-12-01

323

Dendritic cell differentiation from hematopoietic CD34+ progenitor cells.  

PubMed

Dendritic cells (DC) are the most powerful antigen presenting cells (APC) and play a pivotal role in initiating the immune response. In light of their unique properties, DC have been proposed as a tool to enhance immunity against infectious agents and in anticancer vaccine strategies. In the last few years, the development of DC has been extensively investigated. The present paper summarizes the most recent findings on the differentiation of myeloid DC from hematopoietic CD34+ progenitors and methods for DC generation in vitro. A better understanding of DC function has important implications for their use in clinical settings. PMID:11388744

Curti, A; Fogli, M; Ratta, M; Biasco, G; Tura, S; Lemoli, R M

2001-01-01

324

Methylene blue promotes quiescence of rat neural progenitor cells  

PubMed Central

Neural stem cell-based treatment holds a new therapeutic opportunity for neurodegenerative disorders. Here, we investigated the effect of methylene blue on proliferation and differentiation of rat neural progenitor cells (NPCs) both in vitro and in vivo. We found that methylene blue inhibited proliferation and promoted quiescence of NPCs in vitro without affecting committed neuronal differentiation. Consistently, intracerebroventricular infusion of methylene blue significantly inhibited NPC proliferation at the subventricular zone (SVZ). Methylene blue inhibited mTOR signaling along with down-regulation of cyclins in NPCs in vitro and in vivo. In summary, our study indicates that methylene blue may delay NPC senescence through enhancing NPCs quiescence. PMID:25339866

Xie, Luokun; Choudhury, Gourav R.; Wang, Jixian; Park, Yong; Liu, Ran; Yuan, Fang; Zhang, Chun-Li; Yorio, Thomas; Jin, Kunlin; Yang, Shao-Hua

2014-01-01

325

Long GRBs from binary stars: runaway, Wolf-Rayet progenitors  

E-print Network

The collapsar model for long gamma-ray bursts requires a rapidly rotating Wolf-Rayet star as progenitor. We test the idea of producing rapidly rotating Wolf-Rayet stars in massive close binaries through mass accretion and consecutive quasi-chemically homogeneous evolution; the latter had previously been shown to provide collapsars below a certain metallicity threshold for single stars. The binary channel presented here may provide a means for massive stars to obtain the high rotation rates required to evolve quasi-chemically homogeneous and fulfill the collapsar scenario. Moreover, it suggests that a possibly large fraction of long gamma-ray bursts occurs in runaway stars.

M. Cantiello; S. -C. Yoon; N. Langer; M. Livio

2007-09-06

326

Massive binaries, Wolf-Rayet stars and supernova progenitors  

E-print Network

Binary stars are important for a full understanding of stellar evolution. We present a summary of how predictions of the relative supernova rates varies between single and binary stars. We also show how the parameter space of different supernova types differs between single and binary stars. We then consider an important question of how to infer a supernova progenitor's properties from pre-explosion imaging and present rescent work of producing synthe tic colours for our stellar models to make a direct comparison with any detections or limits obtained on supernova progentiors from pre-explosion images.

J. J. Eldridge

2006-12-17

327

Alterations and Abnormal Mitosis of Wheat Chromosomes Induced by Wheat-Rye Monosomic Addition Lines  

PubMed Central

Background Wheat-rye addition lines are an old topic. However, the alterations and abnormal mitotic behaviours of wheat chromosomes caused by wheat-rye monosomic addition lines are seldom reported. Methodology/Principal Findings Octoploid triticale was derived from common wheat T. aestivum L. ‘Mianyang11’×rye S. cereale L. ‘Kustro’ and some progeny were obtained by the controlled backcrossing of triticale with ‘Mianyang11’ followed by self-fertilization. Genomic in situ hybridization (GISH) using rye genomic DNA and fluorescence in situ hybridization (FISH) using repetitive sequences pAs1 and pSc119.2 as probes were used to analyze the mitotic chromosomes of these progeny. Strong pSc119.2 FISH signals could be observed at the telomeric regions of 3DS arms in ‘Mianyang11’. However, the pSc119.2 FISH signals were disappeared from the selfed progeny of 4R monosomic addition line and the changed 3D chromosomes could be transmitted to next generation stably. In one of the selfed progeny of 7R monosomic addition line, one 2D chromosome was broken and three 4A chromosomes were observed. In the selfed progeny of 6R monosomic addition line, structural variation and abnormal mitotic behaviour of 3D chromosome were detected. Additionally, 1A and 4B chromosomes were eliminated from some of the progeny of 6R monosomic addition line. Conclusions/Significance These results indicated that single rye chromosome added to wheat might cause alterations and abnormal mitotic behaviours of wheat chromosomes and it is possible that the stress caused by single alien chromosome might be one of the factors that induced karyotype alteration of wheat. PMID:23936213

Fu, Shulan; Yang, Manyu; Fei, Yunyan; Tan, Feiquan; Ren, Zhenglong; Yan, Benju; Zhang, Huaiyu; Tang, Zongxiang

2013-01-01

328

40 CFR 406.30 - Applicability; description of the normal wheat flour milling subcategory.  

Code of Federal Regulations, 2012 CFR

...Applicability; description of the normal wheat flour milling subcategory. 406.30 Section...MILLS POINT SOURCE CATEGORY Normal Wheat Flour Milling Subcategory § 406.30 Applicability; description of the normal wheat flour milling subcategory. The...

2012-07-01

329

40 CFR 406.30 - Applicability; description of the normal wheat flour milling subcategory.  

Code of Federal Regulations, 2013 CFR

...Applicability; description of the normal wheat flour milling subcategory. 406.30 Section...MILLS POINT SOURCE CATEGORY Normal Wheat Flour Milling Subcategory § 406.30 Applicability; description of the normal wheat flour milling subcategory. The...

2013-07-01

330

40 CFR 406.30 - Applicability; description of the normal wheat flour milling subcategory.  

Code of Federal Regulations, 2011 CFR

...Applicability; description of the normal wheat flour milling subcategory. 406.30 Section...MILLS POINT SOURCE CATEGORY Normal Wheat Flour Milling Subcategory § 406.30 Applicability; description of the normal wheat flour milling subcategory. The...

2011-07-01

331

40 CFR 406.40 - Applicability; description of the bulgur wheat flour milling subcategory.  

Code of Federal Regulations, 2011 CFR

...Applicability; description of the bulgur wheat flour milling subcategory. 406.40 Section...MILLS POINT SOURCE CATEGORY Bulgur Wheat Flour Milling Subcategory § 406.40 Applicability; description of the bulgur wheat flour milling subcategory. The...

2011-07-01

332

40 CFR 406.40 - Applicability; description of the bulgur wheat flour milling subcategory.  

Code of Federal Regulations, 2013 CFR

...Applicability; description of the bulgur wheat flour milling subcategory. 406.40 Section...MILLS POINT SOURCE CATEGORY Bulgur Wheat Flour Milling Subcategory § 406.40 Applicability; description of the bulgur wheat flour milling subcategory. The...

2013-07-01

333

40 CFR 406.40 - Applicability; description of the bulgur wheat flour milling subcategory.  

Code of Federal Regulations, 2012 CFR

...Applicability; description of the bulgur wheat flour milling subcategory. 406.40 Section...MILLS POINT SOURCE CATEGORY Bulgur Wheat Flour Milling Subcategory § 406.40 Applicability; description of the bulgur wheat flour milling subcategory. The...

2012-07-01

334

40 CFR 406.100 - Applicability; description of the wheat starch and gluten subcategory.  

...Applicability; description of the wheat starch and gluten subcategory. 406.100 Section 406...POINT SOURCE CATEGORY Wheat Starch and Gluten Subcategory § 406.100 Applicability; description of the wheat starch and gluten subcategory. The provisions...

2014-07-01

335

40 CFR 406.100 - Applicability; description of the wheat starch and gluten subcategory.  

Code of Federal Regulations, 2013 CFR

...Applicability; description of the wheat starch and gluten subcategory. 406.100 Section 406...POINT SOURCE CATEGORY Wheat Starch and Gluten Subcategory § 406.100 Applicability; description of the wheat starch and gluten subcategory. The provisions...

2013-07-01

336

40 CFR 406.100 - Applicability; description of the wheat starch and gluten subcategory.  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the wheat starch and gluten subcategory. 406.100 Section 406...POINT SOURCE CATEGORY Wheat Starch and Gluten Subcategory § 406.100 Applicability; description of the wheat starch and gluten subcategory. The provisions...

2010-07-01

337

40 CFR 406.100 - Applicability; description of the wheat starch and gluten subcategory.  

Code of Federal Regulations, 2012 CFR

...Applicability; description of the wheat starch and gluten subcategory. 406.100 Section 406...POINT SOURCE CATEGORY Wheat Starch and Gluten Subcategory § 406.100 Applicability; description of the wheat starch and gluten subcategory. The provisions...

2012-07-01

338

40 CFR 406.100 - Applicability; description of the wheat starch and gluten subcategory.  

Code of Federal Regulations, 2011 CFR

...Applicability; description of the wheat starch and gluten subcategory. 406.100 Section 406...POINT SOURCE CATEGORY Wheat Starch and Gluten Subcategory § 406.100 Applicability; description of the wheat starch and gluten subcategory. The provisions...

2011-07-01

339

Seeding rate and seed size as management techniques for ryegrass (Lolium Multiflorum, Lam) in winter wheat  

E-print Network

Higher seeding rates and larger seed sizes could enhance the competitiveness of wheat with ryegrass. Growth room and field research evaluated the effects of wheat seeding rates and seed size in competition with Italian ryegrass. Winter wheat seeds...

Cook, Casey Lee

2005-08-29

340

Three-dimensional perfusion cultivation of human cardiac-derived progenitors facilitates their expansion while maintaining progenitor state.  

PubMed

The therapeutic application of autologous cardiac-derived progenitor cells (CPCs) requires a large cell quantity generated under defined conditions. Herein, we investigated the applicability of a three-dimensional (3D) perfusion cultivation system to facilitate the expansion of CPCs harvested from human heart biopsies and characterized by a relatively high percentage of c-kit(+) cells. The cells were seeded in macroporous alginate scaffolds and after cultivation for 7 days under static conditions, some of the constructs were transferred into a perfusion bioreactor, which was operated for an additional 14 days. A robust and highly reproducible human CPC (hCPC) expansion of more than seven-fold was achieved under the 3D perfusion culture conditions, while under static conditions, the expansion of CPCs was limited only to the first 7 days, after which it leveled-off. On day 21 of perfusion cultivation, the expanded cells exhibited a higher expression level of the progenitor marker c-kit, suggesting that the c-kit-positive CPCs are the main cell population undergoing proliferation. The profile of the spontaneous differentiation in the perfused construct was different from that in the static cultivated constructs; genes typical for cardiac and endothelial cell lineages were more widely expressed in the perfused constructs. By contrast, the differentiation to osteogenic (Von Kossa staining and alkaline phosphatase activity) and adipogenic (Oil Red staining) lineages was reduced in the perfused constructs compared with static cultivated constructs. Collectively, our results indicate that 3D perfusion cultivation mode is an appropriate system for robust expansion of human CPCs while maintaining their progenitor state and differentiation potential into the cardiovascular cell lineages. PMID:24568665

Kryukov, Olga; Ruvinov, Emil; Cohen, Smadar

2014-11-01

341

Reduction in fat uptake of doughnut by microparticulated wheat bran.  

PubMed

Wheat flour-microparticulated wheat bran (MWB) mixture and composites were prepared, and their potential as an oil repellent was evaluated in doughnuts. As MWB content increased, the oil-holding capacity decreased, and there were significant changes in water-holding capacity (p < 0.05). As MWB content increased, the fat content of doughnuts decreased. In addition, the wheat flour-MWB composite was more effective for preventing fat uptake than the wheat flour-MWB mixture. The hardness of the composite was higher than the mixture, although volume and weight decreased and surface colour became darker than that of the mixture. As the proportion of wheat bran in the doughnut formulation increased, the inner crust achieved a uniform cell size and cellular integrity was improved. Based on these data, wheat flour-MWB composites are appropriate for use in doughnut formulas with low fat uptake. PMID:22639853

Kim, Bum-Keun; Chun, Yong-Gi; Cho, Ah-Ra; Park, Dong-June

2012-12-01

342

[Allelopathic effects of companion weed Descurainia sophia on wheat].  

PubMed

By using the techniques of laboratory bioassay, this paper studied the effects of Descurainia sophia extract on the germination rate, germination index, vigor index, root length, shoot height, fresh weight, and dry weight of wheat, and measured the contents of MDA, Chla/Chlb and carotene as well as the karyokinesis index of 5 more sensitive wheat strains. The results showed that D. sophia extract had allelopathic effects on all test wheat strains, though the responses of the strains were significantly different. The test 3 physiological indices of 5 more sensitive wheat strains suggested that the action spot of the allelopathic substances of D. sophia might be the cell membrane of wheat, and the measurement of karyokinesis index indicated that D. sophia extract had inhibitory effects on wheat karyokinesis. PMID:17330486

Yang, Chao; Mu, Xiaoqian

2006-12-01

343

Oat and wheat as contact allergens in personal care products.  

PubMed

Oat and wheat are used as ingredients in various cosmetics and personal care products because of their moisturizing properties. Impaired barrier functions in atopic dermatitis (AD) may increase the risks of sensitization to oat and wheat proteins via skin. Immediate- and delayed-type hypersensitivity reactions to oat and wheat in personal care products have been reported in previous studies, and most of those cases were patients with AD. Patch testing with oat and wheat proteins should be performed more frequently, especially in atopic children. It may help identify contact dermatitis, which may be a cause of flares in patients with AD. Complete avoidance of oat- or wheat-derived products is suggested as we cannot conclude that some oat- or wheat-derived components such as oils are free of protein. PMID:24201466

Pootongkam, Suwimon; Nedorost, Susan

2013-01-01

344

FGF/EGF signaling regulates the renewal of early nephron progenitors during embryonic development  

PubMed Central

Recent studies indicate that nephron progenitor cells of the embryonic kidney are arranged in a series of compartments of an increasing state of differentiation. The earliest progenitor compartment, distinguished by expression of CITED1, possesses greater capacity for renewal and differentiation than later compartments. Signaling events governing progression of nephron progenitor cells through stages of increasing differentiation are poorly understood, and their elucidation will provide key insights into normal and dysregulated nephrogenesis, as well as into regenerative processes that follow kidney injury. In this study, we found that the mouse CITED1+ progenitor compartment is maintained in response to receptor tyrosine kinase (RTK) ligands that activate both FGF and EGF receptors. This RTK signaling function is dependent on RAS and PI3K signaling but not ERK. In vivo, RAS inactivation by expression of sprouty 1 (Spry1) in CITED1+ nephron progenitors results in loss of characteristic molecular marker expression and in increased death of progenitor cells. Lineage tracing shows that surviving Spry1-expressing progenitor cells are impaired in their subsequent epithelial differentiation, infrequently contributing to epithelial structures. These findings demonstrate that the survival and developmental potential of cells in the earliest embryonic nephron progenitor cell compartment are dependent on FGF/EGF signaling through RAS. PMID:22031548

Brown, Aaron C.; Adams, Derek; de Caestecker, Mark; Yang, Xuehui; Friesel, Robert; Oxburgh, Leif

2011-01-01

345

The transcriptome of human CD34 hematopoietic stem-progenitor cells  

E-print Network

The transcriptome of human CD34 hematopoietic stem-progenitor cells Yeong C. Kima,1 , Qingfa Wua,1 for understanding the genetic basis of hematopoiesis. We analyzed gene expression in human CD34 hematopoietic cells that represent the stem-progenitor population (CD34 cells). We collected >459,000 transcript signatures from CD34

346

Lineage Pathway of Human Brain Progenitor Cells Identified by JC Virus Susceptability  

E-print Network

human central nervous system progenitor cells, isolated from human fetal brain tissue by selective central nervous system. Ann Neurol 2003;53:636­646 The differentiation of central nervous system (CNSLineage Pathway of Human Brain Progenitor Cells Identified by JC Virus Susceptability Conrad A

Gronostajski, Richard M.

347

Progenitor cell isolation with a high-capacity quadrupole magnetic flow sorter  

Microsoft Academic Search

Rapid and efficient sorting is important for progenitor cell isolation. Therefore, we have built and evaluated a high-speed, continuous flow, quadrupole magnetic sorter. The cross-over behavior of non-magnetic particles, combined with separation theory is used to optimize performance. CD34+ progenitor cells are separated to purities from 64–95% and a throughput of 107cells\\/s.

Lee R Moore; Alexander R Rodriguez; P. Stephen Williams; Kara McCloskey; Brian J Bolwell; Masayuki Nakamura; Jeffrey J Chalmers; Maciej Zborowski

2001-01-01

348

SOX9 is required for maintenance of the pancreatic progenitor cell pool Scherer, and Maike Sander  

E-print Network

and maintenance factor of multipotential progenitors dur- ing pancreas organogenesis. In the developing pancreas in the adult pancreas are still the subject of debate, neogenesis from a common pool of progenitor cells is the predominant mechanism of cell formation in the embryonic vertebrate pancreas. Progen- itors in the early

Sander, Maike

349

Nrf2 Deficiency Augments the Activity of Hepatic Progenitor Cells during Cholestasis  

E-print Network

regeneration. The aim of the study is to evaluate whether Nrf2 mediates hepatic repair response during, cytokeratin 19 (CK19), a marker of bipotent liver epithelial progenitors and immature billiary epithelial, a marker of liver progenitors, were found to be expressed by newly generated bile duct epithelial cells

Zhou, Yaoqi

350

Epithelial Progeny of Estrogen-Exposed Breast Progenitor Cells Display a Cancer-like Methylome  

Microsoft Academic Search

Estrogen imprinting is used to describe a phenomenon in which early developmental exposure to endocrine disruptors increases breast cancer risk later in adult life. We propose that long-lived, self-regenerating stem and progenitor cells are more susceptible to the exposure injury than terminally differentiated epithelial cells in the breast duct. Mammo- spheres, containing enriched breast progenitors, were used as an exposure

Alfred S. L. Cheng; Aedin C. Culhane; Michael W. Y. Chan; Mathias Ehrich; Aejaz Nasir; Benjamin A. T. Rodriguez; Joseph Liu; Pearlly S. Yan; John Quackenbush; Kenneth P. Nephew; Timothy J. Yeatman

2008-01-01

351

NG2Positive Oligodendrocyte Progenitor Cells in Adult Human Brain and Multiple Sclerosis Lesions  

Microsoft Academic Search

Multiple sclerosis (MS) is characterized by multifocal loss of myelin, oligodendrocytes, and axons. Potential MS therapies include enhancement of remyelination by transplantation or ma- nipulation of endogenous oligodendrocyte progenitor cells. Characteristics of endogenous oligodendrocyte progenitors in normal human brain and in MS lesions have not been studied extensively. This report describes the distribution of cells in sections from normal adult

Ansi Chang; Akiko Nishiyama; John Peterson; John Prineas; Bruce D. Trapp

352

Human palatine tonsil: a new potential tissue source of multipotent mesenchymal progenitor cells  

Microsoft Academic Search

INTRODUCTION: Mesenchymal progenitor cells (MPCs) are multipotent progenitor cells in adult tissues, for example, bone marrow (BM). Current challenges of clinical application of BM-derived MPCs include donor site morbidity and pain as well as low cell yields associated with an age-related decrease in cell number and differentiation potential, underscoring the need to identify alternative sources of MPCs. Recently, MPC sources

Sasa Janjanin; Farida Djouad; Rabie M Shanti; Dolores Baksh; Kiran Gollapudi; Drago Prgomet; Lars Rackwitz; Arjun S Joshi; Rocky S Tuan

2008-01-01

353

Effect of enhanced external counterpulsation on circulating CD34+ progenitor cell subsets  

Microsoft Academic Search

BackgroundEnhanced external counterpulsation (EECP) is associated with improvement in endothelial function, angina and quality of life in patients with symptomatic coronary artery disease, although the mechanisms underlying the observed clinical benefits are not completely clear. The purpose of this study was to examine the effects of EECP on circulating haematopoietic progenitor cells (HPCs) and endothelial progenitor cells (EPCs) in patients

T. J. Kiernan; B. A. Boilson; L. Tesmer; A. Harbuzariu; R. D. Simari; G. W. Barsness

354

The timing of cortical neurogenesis is encoded within lineages of individual progenitor cells  

Microsoft Academic Search

In the developing cerebral cortex, neurons are born on a predictable schedule. Here we show in mice that the essential timing mechanism is programmed within individual progenitor cells, and its expression depends solely on cell-intrinsic and environmental factors generated within the clonal lineage. Multipotent progenitor cells undergo repeated asymmetric divisions, sequentially generating neurons in their normal in vivo order: first

Yue Wang; John T Dimos; Christopher A Fasano; Timothy N Phoenix; Ihor R Lemischka; Natalia B Ivanova; Stefano Stifani; Edward E Morrisey; Sally Temple; Qin Shen

2006-01-01

355

Promotion of rat brain-derived progenitor cell neurogenesis by liquiritigenin treatment: Underlying mechanisms  

Microsoft Academic Search

The purpose of the present study was to determine if liquiritigenin, which is a newly discovered estrogen receptor ? (ER?) agonist, can induce differentiation of brain-derived progenitor cells from rats and to investigate the mechanisms involved. Treatment of brain-derived progenitor cell cultures with liquiritigenin increased the number of cells that differentiated into neurons; but the treatment did not alter the

Rui Ting Liu; Li Bo Zou; Jie Ying Fu; Qiu Jun Lu

2010-01-01

356

A Wolf-Rayet Progenitor for iPTF13bvn?  

NASA Astrophysics Data System (ADS)

Determining the nature of the progenitor stars responsible for core-collapse supernovae (SNe) is a vital problem for massive stellar evolution and, e.g., the chemical history of galaxies. Up to this point, the progenitor, or progenitor systems, responsible for the stripped-envelope Type Ib and Ic SNe are still not understood unambiguously. For the recent Type Ib SN iPTF13bvn in the spiral galaxy NGC 5806, a putative progenitor star was identified at the exact SN position in pre-SN, multi-band HST ACS images. The luminosity and colors for this object have been characterized as being consistent with a single, massive (M_initial > 31--35 Msun) Wolf-Rayet star. Notwithstanding uncertainties in the measurements of the object's brightness and also its host galaxy properties, such as distance and inclination, the progenitor of iPTF13bvn has been suggested by others, instead, to be much less massive and possibly in an interacting binary system. We propose here to deeply reimage the SN site in B and V with WFC3 to determine the status of the putative progenitor, when the SN itself has faded well below the brightness of the progenitor. We will be testing the Wolf-Rayet progenitor scenario and, at the same time, placing constraints on the interacting binary scenario. This can be done in Cycle 22 and only with HST.

Van Dyk, Schuyler

2014-10-01

357

Bio-engineering of stem/progenitor cells Blood stem cell products  

E-print Network

Bio-engineering of stem/progenitor cells Blood stem cell products: Toward sustainable benchmarks expansion of umbilical cord blood (UCB) derived hematopoietic stem and progenitor cells (HSPCs) should stem cell derived products that fulfill our current best known criteria of clinical relevance

Zandstra, Peter W.

358

Noise-Driven Stem Cell and Progenitor Population Martin Hoffmann1  

E-print Network

Noise-Driven Stem Cell and Progenitor Population Dynamics Martin Hoffmann1 *, Hannah H. Chang2 between maintenance of the stem cell state and terminal differentiation is influenced by the cellular present a novel mathematical concept in which stem cell and progenitor population dynamics are described

Bernard, Samuel

359

Progenitor Cell Self-renewal and Cyclic Neutropenia  

PubMed Central

Cyclic neutropenia (CN) is a rare genetic disorder where patients experience regular cycling of neutrophils and various other hematopoietic lineages. The nadir in the neutrophil count is the main source of problems due to the risk of life-threatening infections. Patients with CN benefit from G-CSF therapy although cycling persists. Mutations in the neutrophil elastase gene (ELA2) have been found in more than half of the patients with CN. However, neither the connection between phenotypic expression of ELA2 and CN nor the mechanism of cycling are known. Recently a multi-compartment model of hematopoiesis that couples stem cell replication with marrow output was proposed. In the following, we couple this model of hematopoiesis with a linear feedback mechanism via G-CSF. We propose that the phenotypic effect of ELA2 mutations leads to a reduction in self-renewal of granulocytic progenitors. The body responds by an overall relative increase of G-CSF and increasing progenitor cell self-renewal leading to cell count cycling. The model is compatible with the available experimental data and makes testable predictions. PMID:19397594

Dingli, David; Antal, Tibor; Traulsen, Arne; Pacheco, Jorge M.

2009-01-01

360

Adult stem cell and mesenchymal progenitor theories of aging  

PubMed Central

Advances in medical science and technology allow people live longer lives, which results in age-related problems. Humans cannot avoid the various aged-related alterations of aging; in other words, humans cannot remain young at molecular and cellular levels. In 1956, Harman proposed the “free radical theory of aging” to explain the molecular mechanisms of aging. Telomere length, and accumulation of DNA or mitochondrial damage are also considered to be mechanisms of aging. On the other hand, stem cells are essential for maintaining tissue homeostasis by replacing parenchymal cells; therefore, the stem cell theory of aging is also used to explain the progress of aging. Importantly, the stem cell theory of aging is likely related to other theories. In addition, recent studies have started to reveal the essential roles of tissue-resident mesenchymal progenitors/stem cells/stromal cells in maintaining tissue homeostasis, and some evidence of their fundamental roles in the progression of aging has been presented. In this review, we discuss how stem cell and other theories connect to explain the progress of aging. In addition, we consider the mesenchymal progenitor theory of aging to describing the process of aging. PMID:25364718

Fukada, So-ichiro; Ma, Yuran; Uezumi, Akiyoshi

2014-01-01

361

Bone repair using periodontal ligament progenitor cell-seeded constructs.  

PubMed

The success of tissue-engineering therapies is dependent on the ability of scaffolds to guide differentiation of progenitor cells. Here we present a new approach using a biomimetic construct composed of hydroxyapatite modified with an in vitro-derived extracellular matrix (HA-ECM) and seeded with periodontal ligament progenitor cells (PDLCs). The study aimed to investigate the effect of HA-ECM on osteogenic differentiation of PDLCs and in vivo evaluation of the PDLC-seeded HA-ECM constructs using a rat calvarial critical-sized defect model. After flow-cytometric phenotyping of PDLCs for typical mesenchymal stem cell markers, the PDLCs were cultured on HA-ECM or HA alone in osteogenic media and assessed by MTT, alkaline phosphatase (ALP) assays, and real-time qPCR at different time intervals after seeding. New bone formation induced by PDLC-seeded constructs was assessed by histomorphometric analysis at 12 weeks post-operatively. The PDLCs seeded on HA-ECM showed significantly higher ALP activity and up-regulation of bone-related genes. The treatment with PDLC-seeded HA-ECM significantly improved calvarial bone repair, with the highest amount of newly formed bone elicited by cell-seeded constructs cultured for 14 days. Our results highlight the PDLC-seeded HA-ECM constructs as a promising tool for craniofacial bone regeneration. PMID:22736447

Tour, G; Wendel, M; Moll, G; Tcacencu, I

2012-08-01

362

THE PROGENITOR OF SN 2011ja: CLUES FROM CIRCUMSTELLAR INTERACTION  

SciTech Connect

Massive stars, possibly red supergiants, which retain extended hydrogen envelopes until core collapse, produce Type II plateau (IIP) supernovae. The ejecta from these explosions shocks the circumstellar matter originating from the mass loss of the progenitor during the final phases of its life. This interaction accelerates particles to relativistic energies which then lose energy via synchrotron radiation in the shock-amplified magnetic fields and inverse Compton scattering against optical photons from the supernova. These processes produce different signatures in the radio and X-ray parts of the electromagnetic spectrum. Observed together, they allow us to break the degeneracy between shock acceleration and magnetic field amplification. In this work, we use X-rays observations from the Chandra and radio observations from the Australia Telescope Compact Array to study the relative importance of processes which accelerate particles and those which amplify magnetic fields in producing the non-thermal radiation from SN 2011ja. We use radio observations to constrain the explosion date. Multiple Chandra observations allow us to probe the history of variable mass loss from the progenitor. The ejecta expands into a low-density bubble followed by interaction with a higher density wind from a red supergiant consistent with M{sub ZAMS} {approx}> 12 M{sub Sun }. Our results suggest that a fraction of Type IIP supernovae may interact with circumstellar media set up by non-steady winds.

Chakraborti, Sayan [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Ray, Alak; Yadav, Naveen [Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Colaba, Mumbai 400 005 (India); Smith, Randall [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Ryder, Stuart [Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW 1670 (Australia); Sutaria, Firoza [Indian Institute of Astrophysics, Koramangala, Bangalore (India); Dwarkadas, Vikram V. [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Chandra, Poonam [Department of Physics, Royal Military College of Canada, Kingston, ON K7K 7B4 (Canada); Pooley, David [Department of Physics, Sam Houston State University, Huntsville, TX (United States); Roy, Rupak, E-mail: schakraborti@fas.harvard.edu [Aryabhatta Research Institute of Observational Sciences, Manora Peak, Nainital (India)

2013-09-01

363

Identification of Multipotent Stem/Progenitor Cells in Murine Sclera  

PubMed Central

Purpose. The sclera forms the fibrous outer coat of the eyeball and acts as a supportive framework. The purpose of this study was to examine whether the sclera contains mesenchymal stem/progenitor cells. Method. Scleral tissue from C57BL6/J mice was separated from the retina and choroid and subsequently enzyme digested to release single cells. Proliferation capacity, self-renewal capacity, and ability for multipotent differentiation were analyzed by BrdU labeling, flow cytometry, reverse transcriptase–polymerase chain reaction, immunocytochemistry, and in vivo transplantation. Results. The scleral stem/progenitor cells (SSPCs) possessed clonogenic and high doubling capacities. These cells were positive for the mesenchymal markers Sca-1, CD90.2, CD44, CD105, and CD73 and negative for the hematopoietic markers CD45, CD11b, Flk1, CD34, and CD117. In addition to expressing stem cell genes ABCG2, Six2, Notch1, and Pax6, SSPCs were able to differentiate to adipogenic, chondrogenic, and neurogenic lineages. Conclusions. This study indicates that the sclera contains multipotent mesenchymal stem cells. Further study of SSPCs may help elucidate the cellular and molecular mechanism of scleral diseases such as scleritis and myopia. PMID:21788434

Tsai, Chia-Ling; Wu, Pei-Chang; Fini, M. Elizabeth; Shi, Songtao

2011-01-01

364

A Neutron Star with a Massive Progenitor in Westerlund 1  

E-print Network

We report the discovery of an X-ray pulsar in the young, massive Galactic star cluster Westerlund 1. We detected a coherent signal from the brightest X-ray source in the cluster, CXO J164710.2-455216, during two Chandra observations on 2005 May 22 and June 18. The period of the pulsar is 10.6107(1) s. We place an upper limit to the period derivative of Pdot1 Msun. Taken together, the properties of the pulsar indicate that it is a magnetar. The rarity of slow X-ray pulsars and the position of CXO J164710.2-455216 only 1.6' from the core of Westerlund 1 indicates that it is a member of the cluster with >99.97% confidence. Westerlund 1 contains 07V stars with initial masses M_i=35 Msun and >50 post-main-sequence stars that indicate the cluster is 4+/-1 Myr old. Therefore, the progenitor to this pulsar had an initial mass M_i>40 Msun. This is the most secure result among a handful of observational limits to the masses of the progenitors to neutron stars.

M. P. Muno; J. S. Clark; P. A. Crowther; S. M. Dougherty; R. de Grijs; C. Law; S. L. W. McMillan; M. R. Morris; I. Negueruela; D. Pooley; S. Portegies Zwart; F. Yusef-Zadeh

2005-09-14

365

Dynamical Evolution of the Earth-Moon Progenitors - Whence Theia?  

E-print Network

We present integrations of a model Solar System with five terrestrial planets (beginning ~30-50 Myr after the formation of primitive Solar System bodies) in order to determine the preferred regions of parameter space leading to a giant impact that resulted in the formation of the Moon. Our results indicate which choices of semimajor axes and eccentricities for Theia (the proto-Moon) at this epoch can produce a late Giant Impact, assuming that Mercury, Venus, and Mars are near the current orbits. We find that the likely semimajor axis of Theia, at the epoch when our simulations begin, depends on the assumed mass ratio of Earth-Moon progenitors (8/1, 4/1, or 1/1). The low eccentricities of the terrestrial planets are most commonly produced when the progenitors have similar semimajor axes at the epoch when our integrations commence. Additionally, we show that mean motion resonances among the terrestrial planets and perturbations from the giant planets can affect the dynamical evolution of the system leading to a...

Quarles, Billy

2014-01-01

366

Lin28 sustains early renal progenitors and induces Wilms tumor  

PubMed Central

Wilms Tumor, the most common pediatric kidney cancer, evolves from the failure of terminal differentiation of the embryonic kidney. Here we show that overexpression of the heterochronic regulator Lin28 during kidney development in mice markedly expands nephrogenic progenitors by blocking their final wave of differentiation, ultimately resulting in a pathology highly reminiscent of Wilms tumor. Using lineage-specific promoters to target Lin28 to specific cell types, we observed Wilms tumor only when Lin28 is aberrantly expressed in multiple derivatives of the intermediate mesoderm, implicating the cell of origin as a multipotential renal progenitor. We show that withdrawal of Lin28 expression reverts tumorigenesis and markedly expands the numbers of glomerulus-like structures and that tumor formation is suppressed by enforced expression of Let-7 microRNA. Finally, we demonstrate overexpression of the LIN28B paralog in a significant percentage of human Wilms tumor. Our data thus implicate the Lin28/Let-7 pathway in kidney development and tumorigenesis. PMID:24732380

Urbach, Achia; Yermalovich, Alena; Zhang, Jin; Spina, Catherine S.; Zhu, Hao; Perez-Atayde, Antonio R.; Shukrun, Rachel; Charlton, Jocelyn; Sebire, Neil; Mifsud, William; Dekel, Benjamin; Pritchard-Jones, Kathy; Daley, George Q.

2014-01-01

367

Lin28 sustains early renal progenitors and induces Wilms tumor.  

PubMed

Wilms Tumor, the most common pediatric kidney cancer, evolves from the failure of terminal differentiation of the embryonic kidney. Here we show that overexpression of the heterochronic regulator Lin28 during kidney development in mice markedly expands nephrogenic progenitors by blocking their final wave of differentiation, ultimately resulting in a pathology highly reminiscent of Wilms tumor. Using lineage-specific promoters to target Lin28 to specific cell types, we observed Wilms tumor only when Lin28 is aberrantly expressed in multiple derivatives of the intermediate mesoderm, implicating the cell of origin as a multipotential renal progenitor. We show that withdrawal of Lin28 expression reverts tumorigenesis and markedly expands the numbers of glomerulus-like structures and that tumor formation is suppressed by enforced expression of Let-7 microRNA. Finally, we demonstrate overexpression of the LIN28B paralog in a significant percentage of human Wilms tumor. Our data thus implicate the Lin28/Let-7 pathway in kidney development and tumorigenesis. PMID:24732380

Urbach, Achia; Yermalovich, Alena; Zhang, Jin; Spina, Catherine S; Zhu, Hao; Perez-Atayde, Antonio R; Shukrun, Rachel; Charlton, Jocelyn; Sebire, Neil; Mifsud, William; Dekel, Benjamin; Pritchard-Jones, Kathy; Daley, George Q

2014-05-01

368

Transcription factor induction of human oligodendrocyte progenitor fate and differentiation.  

PubMed

Human oligodendrocyte progenitor cell (OPC) specification and differentiation occurs slowly and limits the potential for cell-based treatment of demyelinating disease. In this study, using FACS-based isolation and microarray analysis, we identified a set of transcription factors expressed by human primary CD140a(+)O4(+) OPCs relative to CD133(+)CD140a(-) neural stem/progenitor cells (NPCs). Among these, lentiviral overexpression of transcription factors ASCL1, SOX10, and NKX2.2 in NPCs was sufficient to induce Sox10 enhancer activity, OPC mRNA, and protein expression consistent with OPC fate; however, unlike ASCL1 and NKX2.2, only the transcriptome of SOX10-infected NPCs was induced to a human OPC gene expression signature. Furthermore, only SOX10 promoted oligodendrocyte commitment, and did so at quantitatively equivalent levels to native OPCs. In xenografts of shiverer/rag2 animals, SOX10 increased the rate of mature oligodendrocyte differentiation and axon ensheathment. Thus, SOX10 appears to be the principle and rate-limiting regulator of myelinogenic fate from human NPCs. PMID:24982138

Wang, Jing; Pol, Suyog U; Haberman, Alexa K; Wang, Chunming; O'Bara, Melanie A; Sim, Fraser J

2014-07-15

369

Chemoattraction of progenitor cells by remodeling extracellular matrix scaffolds.  

PubMed

The chemotactic properties of a biologic scaffold composed of extracellular matrix (ECM) and subjected to in vivo degradation and remodeling were evaluated in a mouse model of Achilles tendon reconstruction. Following a segmental resection of the Achilles tendon in both C57BL/6 and MRL/MpJ mice, the defect was repaired with either an ECM scaffold composed of urinary bladder matrix (UBM) or resected autologous tendon. The surgically repaired and the contralateral tendons were harvested at 3, 7, and 14 days following surgery from each animal. Chemotaxis of multipotential progenitor cells toward the harvested tissue was quantified using a fluorescent-based cell migration assay. Results showed greater migration of progenitor cells toward tendons repaired with UBM-ECM scaffold compared to both the tendons repaired with autologous tissue and the normal contralateral tendon in both the MRL/MpJ and C57BL/6 mice. The magnitude and temporal pattern of the chemotactic response differed between the two mouse strains. PMID:18837648

Beattie, Allison J; Gilbert, Thomas W; Guyot, Juan Pablo; Yates, Adolph J; Badylak, Stephen F

2009-05-01

370

Chemoattraction of Progenitor Cells by Remodeling Extracellular Matrix Scaffolds  

PubMed Central

The chemotactic properties of a biologic scaffold composed of extracellular matrix (ECM) and subjected to in vivo degradation and remodeling were evaluated in a mouse model of Achilles tendon reconstruction. Following a segmental resection of the Achilles tendon in both C57BL/6 and MRL/MpJ mice, the defect was repaired with either an ECM scaffold composed of urinary bladder matrix (UBM) or resected autologous tendon. The surgically repaired and the contralateral tendons were harvested at 3, 7, and 14 days following surgery from each animal. Chemotaxis of multipotential progenitor cells toward the harvested tissue was quantified using a fluorescent-based cell migration assay. Results showed greater migration of progenitor cells toward tendons repaired with UBM–ECM scaffold compared to both the tendons repaired with autologous tissue and the normal contralateral tendon in both the MRL/MpJ and C57BL/6 mice. The magnitude and temporal pattern of the chemotactic response differed between the two mouse strains. PMID:18837648

Beattie, Allison J.; Gilbert, Thomas W.; Guyot, Juan Pablo; Yates, Adolph J.

2009-01-01

371

Wheat resistance to leaf blast mediated by silicon  

Microsoft Academic Search

Blast, caused by Pyricularia grisea, is one of the most important diseases of wheat. The effects of silicon (Si) on this wheat disease were studied. Plants of\\u000a wheat cultivars Aliança and BH-1146 were grown in plastic pots containing Si-deficient soil amended with either calcium silicate\\u000a (+Si) or calcium carbonate (?Si). The content of Si in leaf tissue was significantly increased

M. S. Xavier Filha; F. A. Rodrigues; G. P. Domiciano; H. V. Oliveira; P. R. Silveira; W. R. Moreira

2011-01-01

372

Systematic Spatial Analysis of Gene Expression during Wheat Caryopsis Development W  

E-print Network

but coordinated developmental programs. Because of the hexaploid genome in wheat (Triticum aestivum endosperm is derived from the fertilized polar nuclei. In wheat (Triticum aestivum), the endosperm nuclei

Shaw, Peter

373

Diabetes irreversibly depletes bone marrow-derived mesenchymal progenitor cell subpopulations.  

PubMed

Diabetic vascular pathology is largely attributable to impairments in tissue recovery from hypoxia. Circulating progenitor cells have been postulated to play a role in ischemic recovery, and deficiencies in these cells have been well described in diabetic patients. Here, we examine bone marrow-derived mesenchymal progenitor cells (BM-MPCs) that have previously been shown to be important for new blood vessel formation and demonstrate significant deficits in the context of diabetes. Further, we determine that this dysfunction is attributable to intrinsic defects in diabetic BM-MPCs that are not correctable by restoring glucose homeostasis. We identify two transcriptionally distinct subpopulations that are selectively depleted by both type 1 and type 2 diabetes, and these subpopulations have provasculogenic expression profiles, suggesting that they are vascular progenitor cells. These results suggest that the clinically observed deficits in progenitor cells may be attributable to selective and irreversible depletion of progenitor cell subsets in patients with diabetes. PMID:24740572

Januszyk, Michael; Sorkin, Michael; Glotzbach, Jason P; Vial, Ivan N; Maan, Zeshaan N; Rennert, Robert C; Duscher, Dominik; Thangarajah, Hariharan; Longaker, Michael T; Butte, Atul J; Gurtner, Geoffrey C

2014-09-01

374

Growth factor- and cytokine-stimulated endothelial progenitor cells in post-ischemic cerebral neovascularization  

PubMed Central

Endothelial progenitor cells are resident in the bone marrow blood sinusoids and circulate in the peripheral circulation. They mobilize from the bone marrow after vascular injury and home to the site of injury where they differentiate into endothelial cells. Activation and mobilization of endothelial progenitor cells from the bone marrow is induced via the production and release of endothelial progenitor cell-activating factors and includes specific growth factors and cytokines in response to peripheral tissue hypoxia such as after acute ischemic stroke or trauma. Endothelial progenitor cells migrate and home to specific sites following ischemic stroke via growth factor/cytokine gradients. Some growth factors are less stable under acidic conditions of tissue ischemia, and synthetic analogues that are stable at low pH may provide a more effective therapeutic approach for inducing endothelial progenitor cell mobilization and promoting cerebral neovascularization following ischemic stroke.

Peplow, Philip V.

2014-01-01

375

The Earliest Thymic T Cell Progenitors Sustain B Cell and Myeloid Lineage Potentials  

PubMed Central

The stepwise commitment from hematopoietic stem cells in the bone marrow (BM) to T lymphocyte-restricted progenitors in the thymus represents a paradigm for understanding the requirement for distinct extrinsic cues during different stages of lineage restriction from multipotent to lineage restricted progenitors. However, the commitment stage at which progenitors migrate from the BM to the thymus remains unclear. Here we provide functional and molecular evidence at the single cell level that the earliest progenitors in the neonatal thymus possessed combined granulocyte-monocyte, T and B lymphocyte, but not megakaryocyte-erythroid lineage potential. These potentials were identical to those of thymus-seeding progenitors in the BM, which were closely related at the molecular level. These findings establish the distinct lineage-restriction stage at which the T lineage commitment transits from the BM to the remote thymus. PMID:22344248

Luc, Sidinh; Luis, Tiago C.; Boukarabila, Hanane; Macaulay, Iain C.; Buza-Vidas, Natalija; Bouriez-Jones, Tiphaine; Lutteropp, Michael; Woll, Petter S.; Loughran, Stephen J.; Mead, Adam J.; Hultquist, Anne; Brown, John; Mizukami, Takuo; Matsuoka, Sahoko; Ferry, Helen; Anderson, Kristina; Duarte, Sara; Atkinson, Deborah; Soneji, Shamit; Domanski, Aniela; Farley, Alison; Sanjuan-Pla, Alejandra; Carella, Cintia; Patient, Roger; de Bruijn, Marella; Enver, Tariq; Nerlov, Claus; Blackburn, Clare; Godin, Isabelle; Jacobsen, Sten Eirik W.

2012-01-01

376

Cellular plasticity: the good, the bad, and the ugly? Microenvironmental influences on progenitor cell therapy.  

PubMed

Progenitor cell based therapies have emerged for the treatment of ischemic cardiovascular diseases where there is insufficient endogenous repair. However, clinical success has been limited, which challenges the original premise that transplanted progenitor cells would orchestrate repair. In this review, we discuss the basics of endothelial progenitor cell therapy and describe how microenvironmental changes (i.e., trophic and mechano-structural factors) in the damaged myocardium influence progenitor cell plasticity and hamper beneficial therapeutic outcome. Further understanding of these microenvironmental clues will enable optimization of cell therapy at all levels. We discuss current concepts and provide future perspectives for the enhancement of progenitor cell therapy, and merge these advances into a combined approach for ischemic tissue repair. PMID:22356658

Moonen, Jan-Renier A J; Harmsen, Martin C; Krenning, Guido

2012-03-01

377

Evaluation of trends in wheat yield models  

NASA Technical Reports Server (NTRS)

Trend terms in models for wheat yield in the U.S. Great Plains for the years 1932 to 1976 are evaluated. The subset of meteorological variables yielding the largest adjusted R(2) is selected using the method of leaps and bounds. Latent root regression is used to eliminate multicollinearities, and generalized ridge regression is used to introduce bias to provide stability in the data matrix. The regression model used provides for two trends in each of two models: a dependent model in which the trend line is piece-wise continuous, and an independent model in which the trend line is discontinuous at the year of the slope change. It was found that the trend lines best describing the wheat yields consisted of combinations of increasing, decreasing, and constant trend: four combinations for the dependent model and seven for the independent model.

Ferguson, M. C.

1982-01-01

378

Wheat seed proteins regulated by imbibition independent of dormancy status.  

PubMed

Seed dormancy is an important trait in wheat (Trticum aestivum L.) and it can be released by germination-stimulating treatments such as after-ripening. Previously, we identified proteins specifically associated with after-ripening mediated developmental switches of wheat seeds from the state of dormancy to germination. Here, we report seed proteins that exhibited imbibition induced co-regulation in both dormant and after-ripened seeds of wheat, suggesting that the expression of these specific proteins/protein isoforms is not associated with the maintenance or release of seed dormancy in wheat. PMID:24084602

Park, Seokhoon; Rampitsch, Christof; Humphreys, Gavin D; Ayele, Belay T

2013-01-01

379

Physical mapping of wheat aquaporin genes  

Microsoft Academic Search

Aquaporins are water channel proteins that control the flow of water across cellular membranes and play vital roles in all\\u000a aspects of plant–water relations. Our previous identification of 35 wheat PIP and TIP aquaporin genes showed they formed a large family with many conserved features that are thought to be important in structure\\u000a and function. The present work focussed on

Kerrie L. Forrest; Mrinal Bhave

2010-01-01

380

Explosion pulping of bagasse and wheat straw  

SciTech Connect

Bagasse and wheat straw were soda-pulped in a digester at 200 degrees under N pressure of up to 13.8 MPa, followed by explosive discharge through nozzles to give pulp having lower yield and higher initial freeness than batch soda pulp. Explosion pulping required less NaOH than conventional batch soda pulping, and the properties of explosion pulp obtained were similar to those of batch soda pulp at a given freeness.

Mamers, H.; Yuritta, J.P.; Menz, D.J.

1981-01-01

381

Cation amelioration of aluminum toxicity in wheat  

Microsoft Academic Search

Aluminum is a major constituent of most soils and limits crop productivity in many regions. Amelioration is of theoretical as well as practical interest because understanding amelioration may contribute to an understanding of the mechanisms of toxicity. In the experiments reported here 2-day-old wheat (Triticum aestivum L. cv Tyler) seedlings with 15-millimeter roots were transferred to solutions containing 0.4 millimolar

T. B. Kinraide; D. R. Parker

1987-01-01

382

Silicon accumulation and water uptake by wheat  

Microsoft Academic Search

Silicon (Si) content in cereal plants and soil-Si solubility may be used to estimate transpiration, assuming passive Si uptake. The hypothesis for passive-Si uptake by the transpiration stream was tested in wheat (Triticum aestivum cv. Stephens) grown on the irrigated Portneuf silt loam soil (Durixerollic calciorthid) near Twin Falls, Idaho. Treatments consisted of 5 levels of plant-available soil water ranging

H. F. Mayland; J. L. Wright; R. E. Sojka

1991-01-01

383

Azospirillum inoculation in pregerminating wheat seeds  

Microsoft Academic Search

Azospirillum cells were inoculated in pregerminating wheat during seed imbibition. Surface-sterilized seeds of Triticum aestivum cv. Buck Pucara were sequentially soaked for 3 h in water and 3 h in the inoculum of 3 x lo8 Azospirillum brasilense Sp 245 cells. rnL-I, to allow bacteria to enter during imbibition. Germination and seedling growth were accomplished in sterile distilled water at

Cecilia M. Creus; Rolando J. Sueldo; Carlos A. Barassi

1996-01-01

384

Amyl expression during wheat seed germination  

Microsoft Academic Search

The expression pattern of ?-Amyl, a gene coding for high-pI ?-amylase, has been studied during wheat (Triticum aestivum) seed germination using both Northern-blot and in situ hybridisation. At early stages of germination (24 h after imbibition) this gene was exclusively expressed in the scutellar epithelium. The expression in this tissue was transient and independent of GA3. At later stages of

Francisco J. Cejudo; María T. Cubo; David C. Baulcombe

1995-01-01

385

Zirconium induced physiological alterations in wheat seedlings  

Microsoft Academic Search

The effects of zirconium ascorbate (Zr-ASC), a water-soluble complex of Zr, were examined on wheat seedlings (Triticum aestivum L. cv. MV. 20). Hydroponically grown plants were exposed to 10, 33, 55, 100 and 550 µM Zr-ASC (Zr10, Zr33etc.). After 9 d of treatment inhibition of germination, retarded root and shoot growth, and increased activities of antioxidant enzymes (guaiacol peroxidase, ascorbate

M. Fodor; A. Hegedus; E. Stefanovits-Banyai

2005-01-01

386

Roles of nonmyogenic mesenchymal progenitors in pathogenesis and regeneration of skeletal muscle  

PubMed Central

Adult skeletal muscle possesses a remarkable regenerative ability that is dependent on satellite cells. However, skeletal muscle is replaced by fatty and fibrous connective tissue in several pathological conditions. Fatty and fibrous connective tissue becomes a major cause of muscle weakness and leads to further impairment of muscle function. Because the occurrence of fatty and fibrous connective tissue is usually associated with severe destruction of muscle, the idea that dysregulation of the fate switch in satellite cells may underlie this pathological change has emerged. However, recent studies identified nonmyogenic mesenchymal progenitors in skeletal muscle and revealed that fatty and fibrous connective tissue originates from these progenitors. Later, these progenitors were also demonstrated to be the major contributor to heterotopic ossification in skeletal muscle. Because nonmyogenic mesenchymal progenitors represent a distinct cell population from satellite cells, targeting these progenitors could be an ideal therapeutic strategy that specifically prevents pathological changes of skeletal muscle, while preserving satellite cell-dependent regeneration. In addition to their roles in pathogenesis of skeletal muscle, nonmyogenic mesenchymal progenitors may play a vital role in muscle regeneration by regulating satellite cell behavior. Conversely, muscle cells appear to regulate behavior of nonmyogenic mesenchymal progenitors. Thus, these cells regulate each other reciprocally and a proper balance between them is a key determinant of muscle integrity. Furthermore, nonmyogenic mesenchymal progenitors have been shown to maintain muscle mass in a steady homeostatic condition. Understanding the nature of nonmyogenic mesenchymal progenitors will provide valuable insight into the pathophysiology of skeletal muscle. In this review, we focus on nonmyogenic mesenchymal progenitors and discuss their roles in muscle pathogenesis, regeneration, and homeostasis. PMID:24605102

Uezumi, Akiyoshi; Ikemoto-Uezumi, Madoka; Tsuchida, Kunihiro

2014-01-01

387

Arabidopsis –rice–wheat gene orthologues for Na + transport and transcript analysis in wheat– L. elongatum aneuploids under salt stress  

Microsoft Academic Search

Lophopyrum elongatum is a wild relative of wheat that provides a source of novel genes for improvement of the salt tolerance of bread wheat. Improved\\u000a Na+ ‘exclusion’ is associated with salt tolerance in a wheat–L. elongatum amphiploid, in which a large proportion (ca. 50%) of the improved regulation of leaf Na+ concentrations is controlled by chromosome 3E. In this study,

Daniel J. Mullan; Timothy D. Colmer; Michael G. Francki

2007-01-01

388

Profiling of mitochondrial proteome in wheat roots.  

PubMed

Mitochondria are important organelles for cellular respiration within the eukaryotic cell and have many important functions including vitamin synthesis, amino acid metabolism and photorespiration. To investigate the mitochondrial proteome of the roots of wheat seedlings, a systematic and targeted analysis were carried out on the mitochondrial proteome from 15 day-old wheat seedling root material. Mitochondria were isolated by Percoll gradient centrifugation; and extracted proteins were disassociated and analyzed by Tricine SDS-PAGE couple to LTQ-FTICR mass spectrometry. From the isolated the sample, 184 proteins were identified which is composed of 140 proteins as mitochondria and 44 proteins as other subcellular proteins that are predicted by the freeware sub-cellular predictor. The identified proteins in mitochondria were functionally classified into 12 classes using the ProtFun 2.2 servers based on biological processes. Proteins were shown to be involved in amino acid biosynthesis (17.1%), biosynthesis of cofactors (6.4%), cell envelope (11.4%), central intermediary metabolism (10%), energy metabolism (20%), fatty acid metabolism (0.7%), purines and pyrimidines (5.7%), regulatory functions (0.7%), replication and transcription (1.4%), translation (22.1%), transport and binding (1.4%), and unknown (2.8%). These results indicate that many of the protein components present and functions of identifying proteins are common to other profiles of mitochondrial proteins performed to date. These results are provided the extensive and noble clues, to our knowledge, of mitochondrial proteins from wheat roots. PMID:24958017

Kim, Da-Eun; Roy, Swapan Kumar; Kamal, Abu Hena Mostafa; Cho, Kun; Kwon, Soo Jeong; Cho, Seong-Woo; Park, Chul-Soo; Choi, Jong-Soon; Komatsu, Setsuko; Lee, Moon-Soon; Woo, Sun-Hee

2014-08-01

389

Cytogenetic identification of Aegilops squarrosa chromosome additions in durum wheat.  

PubMed

A set of four normal chromosomes (1D, 2D, 3D, and 6D), and three translocation chromosomes (4DS·5DS, 5DL·7DS, and 7DL·4DL) involving all 14 chromosome arms of the D-genome were obtained as monosomic additions from Aegilops squarrosa (genome D, n=7) in Triticum durum Desf. cv 'PBW114' (genome AB, n=14). The cyclical translocation occurred during the synthesis of the amphiploid probably as a result of misdivision and reunion of the univalents during meiosis of the F1 hybrid T. durum x A. Squarrosa. The amphiploid was backcrossed twice with the durum parent to obtain monosomic addition lines. The monosomic addition chromosomes were identified by C-banding and associated phenotypic traits. All monosomic addition lines were fertile. The development of disomic and ditelosomic addition lines is underway, which will be useful for cytogenetic analysis of individual D-genome chromosomes in the background of T. Durum. PMID:24226737

Dhaliwal, H S; Friebe, B; Gill, K S; Gill, B S

1990-06-01

390

Effects of Wheat Bug (Eurygaster spp. and Aelia spp.) Infestation in Preharvest Period on Wheat Technological Quality and Gluten Composition  

PubMed Central

The effects of wheat bug infestation (Eurygaster spp. and Aelia spp.) on the composition of wheat gluten proteins and its influence on flour technological quality were investigated in the present study. Wheat samples of six wheat varieties, collected from two localities in northern Serbia, were characterized by significantly different level of wheat bug infestation. Composition of wheat gluten proteins was determined using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS PAGE), while the selected parameters of technological quality were determined according to standard and modified empirical rheological methods (Farinograph, Extensograph, Alveograph, and Gluten Index). The surface morphology of the selected samples was viewed using scanning electron microscopy (SEM). Wheat from wheat bug-infested locality regardless of the variety had deteriorated technological quality expressed with higher Farinograph softening degree, lower or immeasurable Extensograph energy, and Alveograph deformation energy. The most important changes in the gluten proteins composition of bug-infested wheat were related to gliadin subunits with molecular weights below 75?kDa, which consequently caused deterioration of uniaxial and biaxial extensibility and dough softening during mixing. PMID:24550692

Torbica, Aleksandra M.; Mastilovic, Jasna S.; Pojic, Milica M.; Kevresan, Zarko S.

2014-01-01

391

Progenitor neutron stars of the lightest and heaviest millisecond pulsars  

E-print Network

Recent mass measurements of two binary millisecond pulsars, PSR J1614-2230 and PSR J0751+1807 with a mass M=1.97+/-0.04 Msun and M=1.26+/-0.14 Msun respectively indicate a large span of masses for such objects, and possibly also a broad spectrum of neutron star masses born in core-collapse supernovae. Starting from a zero-age main sequence binary stage, we aim at inferring the masses of the progenitor neutron star of PSR J1614-2230 and PSR J0751+1807 by taking into account the differences in the evolutionary stages preceding their formation. Using simulations for the evolution of binary stars we reconstruct the evolutionary tracks leading to the formation of PSR J1614-2230 and PSR J0751+1807. We analyse in detail the spin evolution due to the accretion of matter from a disk in the medium-mass/low-mass X-ray binary. General relativistic effects and the damping of surface magnetic field associated with accretion are accounted for. We consider two equations of state of dense matter, one for purely nucleonic matter and the other one including a high density softening due to the appearance of hyperons, together with a selection of models for the neutron star magnetic field and its decay. The estimated mass of the progenitor neutron stars of PSR J0751+1807 and PSR J1614-2230 could be as small as 1.1 Msun and 1.9 Msun, respectively. These values weakly depend on the equation of state and the assumed model for the polar magnetic field and its accretion-induced decay. The masses of progenitor neutron star of recycled pulsars span over a broad interval, from 1.1 Msun to 1.9 Msun. Including the effect of a slow Roche-lobe detachment phase, which as suggested recently by Tauris could be relevant for PSR J0751+1807, would make the lower mass limit even smaller. A realistic theory for core-collapse supernovae should account for this large range of mass.

M. Fortin; M. Bejger; P. Haensel; J. L. Zdunik

2014-09-03

392

Electron-capture supernovae exploding within their progenitor wind  

NASA Astrophysics Data System (ADS)

The most massive stars on the asymptotic giant branch (AGB), or the so-called super-AGB stars, are thought to produce supernovae triggered by electron captures in their degenerate O+Ne+Mg cores. Super-AGB stars are expected to have slow winds with high mass-loss rates, so their circumstellar density is high. The explosions of super-AGB stars are therefore presumed to occur in this dense circumstellar environment. We provide the first synthetic light curves for such events by exploding realistic electron-capture supernova progenitors within their super-AGB winds. We find that the early light curve - that is, before the recombination wave reaches the bottom of the hydrogen-rich envelope of supernova ejecta (the plateau phase) - is not affected by the dense wind. However, after the luminosity drop following the plateau phase, the luminosity remains much higher when the super-AGB wind is taken into account. We compare our results to the historical light curve of SN 1054, the progenitor of the Crab Nebula, and show that the explosion of an electron-capture supernova within an ordinary super-AGB wind can explain the observed light curve features. We conclude that SN 1054 could have been a Type IIn supernova without any extra extreme mass loss, which was previously suggested to be necessary to account for its early high luminosity. We also show that our light curves match Type IIn supernovae with an early plateau phase or the so-called Type IIn-P supernovae, and suggest that they are electron-capture supernovae within super-AGB winds. Although some electron-capture supernovae can be bright in the optical spectral range due to the large progenitor radius, their X-ray luminosity from the interaction does not necessarily get as bright as other Type IIn supernovae whose optical luminosities are also powered by the interaction. Thus, we suggest that optically bright X-ray-faint Type IIn supernovae can emerge from electron-capture supernovae. Optically faint Type IIn supernovae, such as SN 2008S, can also originate from electron-capture supernovae if their hydrogen-rich envelope masses are small. We argue that some of them can be observed as Type IIn-b supernovae due to the small hydrogen-rich envelope mass.

Moriya, Takashi J.; Tominaga, Nozomu; Langer, Norbert; Nomoto, Ken'ichi; Blinnikov, Sergei I.; Sorokina, Elena I.

2014-09-01

393

Genetic basis for spontaneous hybrid genome doubling during allopolyploid speciation of common wheat shown by natural variation analyses of the paternal species.  

PubMed

The complex process of allopolyploid speciation includes various mechanisms ranging from species crosses and hybrid genome doubling to genome alterations and the establishment of new allopolyploids as persisting natural entities. Currently, little is known about the genetic mechanisms that underlie hybrid genome doubling, despite the fact that natural allopolyploid formation is highly dependent on this phenomenon. We examined the genetic basis for the spontaneous genome doubling of triploid F1 hybrids between the direct ancestors of allohexaploid common wheat (Triticum aestivum L., AABBDD genome), namely Triticumturgidum L. (AABB genome) and Aegilopstauschii Coss. (DD genome). An Ae. tauschii intraspecific lineage that is closely related to the D genome of common wheat was identified by population-based analysis. Two representative accessions, one that produces a high-genome-doubling-frequency hybrid when crossed with a T. turgidum cultivar and the other that produces a low-genome-doubling-frequency hybrid with the same cultivar, were chosen from that lineage for further analyses. A series of investigations including fertility analysis, immunostaining, and quantitative trait locus (QTL) analysis showed that (1) production of functional unreduced gametes through nonreductional meiosis is an early step key to successful hybrid genome doubling, (2) first division restitution is one of the cytological mechanisms that cause meiotic nonreduction during the production of functional male unreduced gametes, and (3) six QTLs in the Ae. tauschii genome, most of which likely regulate nonreductional meiosis and its subsequent gamete production processes, are involved in hybrid genome doubling. Interlineage comparisons of Ae. tauschii's ability to cause hybrid genome doubling suggested an evolutionary model for the natural variation pattern of the trait in which non-deleterious mutations in six QTLs may have important roles. The findings of this study demonstrated that the genetic mechanisms for hybrid genome doubling could be studied based on the intrinsic natural variation that exists in the parental species. PMID:23950867

Matsuoka, Yoshihiro; Nasuda, Shuhei; Ashida, Yasuyo; Nitta, Miyuki; Tsujimoto, Hisashi; Takumi, Shigeo; Kawahara, Taihachi

2013-01-01

394

SWI/SNF in cardiac progenitor cell differentiation  

PubMed Central

Cardiogenesis requires proper specification, proliferation, and differentiation of cardiac progenitor cells (CPCs). The differentiation of CPCs to specific cardiac cell types is likely guided by a comprehensive network comprised of cardiac transcription factors and epigenetic complexes. In this review, we describe how the ATP-dependent chromatin remodeling SWI/SNF complexes work synergistically with transcription and epigenetic factors to direct specific cardiac gene expression during CPC differentiation. Furthermore, we discuss how SWI/SNF may prime chromatin for cardiac gene expression at a genome-wide level. A detailed understanding of SWI/SNF-mediated CPC differentiation will provide important insight into the etiology of cardica defects and help design novel therapies for heart disease. PMID:23606236

Lei, Ienglam; Liu, Liu; Sham, Mai Har; Wang, Zhong

2014-01-01

395

Subluminous B Stars and Progenitors of Helium Core White Dwarfs  

E-print Network

Subluminous B (sdB) stars can result from stable Roche lobe overflow or common envelope ejection in close binary systems. The companions are either low mass main sequence stars or white dwarfs. We discuss mass determinations for sdB stars from such systems and report the discovery of the bright nearby sdB star, HD 188112, to be a close binary system of unusually low mass (0.23 solar masses). From the mass function it is evident that the companion is a massive compact object of at least 0.72 solar masses. The mass of the sdB HD 188112 is too low for the star to evolve into a C/O white dwarf, but it probably is a progenitor for a helium core white dwarf.

U. Heber

2002-12-20

396

The Masses of M31 Supernova Remnant Progenitors  

NASA Astrophysics Data System (ADS)

We propose to expand our previous successful archival program to constrain the progenitor masses of supernova remnants {SNRs} in M31. Our previous program has resulted in 2 papers that each significantly improve our knowledge of the mass distribution of stars that produce supernovae. However, a new and significantly improved SNR catalog has been released this year, which is more comprehensive and reliable that anything available at the time of our previous program. The amount of high-quality HST imaging has also increased. This new catalog provides 106 SNRs with HST coverage, 67 of which were not measured by our previous archival program. Furthermore, our technique for measuring uncertainties in our mass estimates has become more reliable. This expanded and updated program will increase the number of measurements SNRs by a factor of 2, while also producing a much cleaner, more homogeneous sample.

Williams, Benjamin

2014-10-01

397

Endothelial Progenitors as Tools to Study Vascular Disease  

PubMed Central

Endothelial progenitor cells (EPCs) have great clinical value because they can be used as diagnostic biomarkers and as a cellular therapy for promoting vascular repair of ischaemic tissues. However, EPCs also have an additional research value in vascular disease modelling to interrogate human disease mechanisms. The term EPC is used to describe a diverse variety of cells, and we have identified a specific EPC subtype called outgrowth endothelial cell (OEC) as the best candidate for vascular disease modelling because of its high-proliferative potential and unambiguous endothelial commitment. OECs are isolated from human blood and can be exposed to pathologic conditions (forward approach) or be isolated from patients (reverse approach) in order to study vascular human disease. The use of OECs for modelling vascular disease will contribute greatly to improving our understanding of endothelial pathogenesis, which will potentially lead to the discovery of novel therapeutic strategies for vascular diseases. PMID:22550504

Medina, Reinhold J.; O'Neill, Christina L.; O'Doherty, T. Michelle; Wilson, Sarah E. J.; Stitt, Alan W.

2012-01-01

398

Amnion-derived multipotent progenitor cells support allograft tolerance induction.  

PubMed

Donor-specific immunological tolerance using high doses of bone marrow cells (BMCs) has been demonstrated in mixed chimerism-based tolerance induction protocols; however, the development of graft versus host disease remains a risk. Here, we demonstrate that the co-infusion of limited numbers of donor unfractionated BMCs with human amnion-derived multipotent progenitor cells (AMPs) 7 days post-allograft transplantation facilitates macrochimerism induction and graft tolerance in a mouse skin transplantation model. AMPs + BMCs co-infusion with minimal conditioning led to stable, mixed, multilineage lymphoid and myeloid macrochimerism, deletion of donor-reactive T cells, expansion of CD4(+)CD25(+)Foxp3(+) regulatory T cells (T(regs)) and long-term allograft survival (>300 days). Based on these findings, we speculate that AMPs maybe a pro-tolerogenic cellular therapeutic that could have clinical efficacy for both solid organ and hematopoietic stem cell transplant applications. PMID:23651511

Anam, K; Lazdun, Y; Davis, P M; Banas, R A; Elster, E A; Davis, T A

2013-06-01

399

Identification and potential application of human corneal endothelial progenitor cells.  

PubMed

The corneal endothelium is believed to be developmentally originated from the periocular mesenchyme via the neural crest. Human corneal endothelial progenitor cells (HCEPs) have been investigated because of their potential availability for the tissue regenerative medicine. However, the existence and the properties of HCEPs have not been elucidated yet. We first established a novel serum-free culture system for HCEPs. The HCEPs highly expressed p75 neurotrophin receptor, SOX9, and FOXC2, and partially retained the properties of neural crest and periocular mesenchyme. Further, we demonstrated that HCEPs had a high proliferative potency, and the differentiated HCEP sheets had corneal endothelial function by using the Ussing chamber system and transplantation to the rabbit cornea. These findings suggest that the HCEPs can be selectively expanded from the corneal endothelium using a specific culture system and will provide cell sheets for corneal regenerative medicine. PMID:24588720

Hara, Susumu; Hayashi, Ryuhei; Soma, Takeshi; Kageyama, Tomofumi; Duncan, Thomas; Tsujikawa, Motokazu; Nishida, Kohji

2014-09-15

400

Conjugated Polyelectrolyte Materials for Promoting Progenitor Cell Growth Without Serum  

NASA Astrophysics Data System (ADS)

The discovery of new active biomaterials for promoting progenitor cell growth and differentiation in serum-free medium is still proving more challenging for the clinical treatments of degenerative diseases. In this work, a conjugated polyelectrolyte, polythiophene derivative (PMNT), was discovered to significantly drive the cell cycle progression from G1 to S and G2 phases and thus efficiently promote the cell growth without the need of serum. Furthermore, the fluorescent characteristic of PMNT makes it simultaneously able to trace its cellular uptake and localization by cell imaging. cDNA microarray study shows that PMNT can greatly regulate genes related to cell growth or differentiation. To the best of our knowledge, this is the first example of cell growth or differentiation promotion by polyelectrolyte material without the need of serum, thereby providing an important demonstration of degenerative biomaterial discovery through polymer design.

Yang, Gaomai; Liu, Libing; Lv, Fengting; Wang, Shu

2013-04-01

401

Conjugated polyelectrolyte materials for promoting progenitor cell growth without serum.  

PubMed

The discovery of new active biomaterials for promoting progenitor cell growth and differentiation in serum-free medium is still proving more challenging for the clinical treatments of degenerative diseases. In this work, a conjugated polyelectrolyte, polythiophene derivative (PMNT), was discovered to significantly drive the cell cycle progression from G? to S and G? phases and thus efficiently promote the cell growth without the need of serum. Furthermore, the fluorescent characteristic of PMNT makes it simultaneously able to trace its cellular uptake and localization by cell imaging. cDNA microarray study shows that PMNT can greatly regulate genes related to cell growth or differentiation. To the best of our knowledge, this is the first example of cell growth or differentiation promotion by polyelectrolyte material without the need of serum, thereby providing an important demonstration of degenerative biomaterial discovery through polymer design. PMID:23609105

Yang, Gaomai; Liu, Libing; Lv, Fengting; Wang, Shu

2013-01-01

402

Conjugated Polyelectrolyte Materials for Promoting Progenitor Cell Growth Without Serum  

PubMed Central

The discovery of new active biomaterials for promoting progenitor cell growth and differentiation in serum-free medium is still proving more challenging for the clinical treatments of degenerative diseases. In this work, a conjugated polyelectrolyte, polythiophene derivative (PMNT), was discovered to significantly drive the cell cycle progression from G1 to S and G2 phases and thus efficiently promote the cell growth without the need of serum. Furthermore, the fluorescent characteristic of PMNT makes it simultaneously able to trace its cellular uptake and localization by cell imaging. cDNA microarray study shows that PMNT can greatly regulate genes related to cell growth or differentiation. To the best of our knowledge, this is the first example of cell growth or differentiation promotion by polyelectrolyte material without the need of serum, thereby providing an important demonstration of degenerative biomaterial discovery through polymer design. PMID:23609105

Yang, Gaomai; Liu, Libing; Lv, Fengting; Wang, Shu

2013-01-01

403

Migrating Oligodendrocyte Progenitor Cells Swell Prior to Soma Dislocation  

PubMed Central

The migration of oligodendrocyte progenitor cells (OPCs) to the white matter is an indispensable requirement for an intact brain function. The mechanism of cell migration in general is not yet completely understood. Nevertheless, evidence is accumulating that besides the coordinated rearrangement of the cytoskeleton, a finetuned interplay of ion and water fluxes across the cell membrane is essential for cell migration. One part of a general hypothesis is that a local volume increase towards the direction of movement triggers a mechano-activated calcium influx that regulates various procedures at the rear end of a migrating cell. Here, we investigated cell volume changes of migrating OPCs using scanning ion conductance microscopy. We found that during accelerated migration OPCs undergo an increase in the frontal cell body volume. These findings are supplemented with time lapse calcium imaging data that hint an increase in calcium content the frontal part of the cell soma. PMID:23657670

Happel, Patrick; Moller, Kerstin; Schwering, Nina K.; Dietzel, Irmgard D.

2013-01-01

404

Effects of physical activity on endothelial progenitor cells (EPCs)  

PubMed Central

Physical activity has a therapeutic role in cardiovascular disease (CVD), through its beneficial effects on endothelial function and cardiovascular system. Circulating endothelial progenitor cells (EPCs) are bone marrow (BM) derived cells that represent a novel therapeutic target in CVD patients, because of their ability to home to sites of ischemic injury and repair the damaged vessels. Several studies show that physical activity results in a significant increase in circulating EPCs, and, in particular, there are some evidence of the beneficial exercise-induced effects on EPCs activity in CVD settings, including coronary artery disease (CAD), heart failure (HF), and peripheral artery disease (PAD). The aim of this paper is to review the current evidence about the beneficial effects of physical exercise on endothelial function and EPCs levels and activity in both healthy subjects and patients with CVD. PMID:24550833

De Biase, Chiara; De Rosa, Roberta; Luciano, Rossella; De Luca, Stefania; Capuano, Ernesto; Trimarco, Bruno; Galasso, Gennaro

2014-01-01

405

Production of interleukin 1beta by human hematopoietic progenitor cells.  

PubMed Central

The production of interleukin 1beta (IL-1beta) by human hematopoietic stem/progenitor cells was studied to explore the concept that these cells are not merely responders to stimuli from their microenvironment, but can themselves produce a powerful biomodulator. Cells with a CD34+ CD45RA(lo) CD71(lo) phenotype were purified from human umbilical cord blood and cultured one per well in serum-free medium with a mixture of cytokines. Cells that had divided over 2-5 d to form doublets were identified and the daughter cells were studied individually. 91% (460/506) of daughter cells had clonogenic potential. Analysis of these individual daughter cells by reverse transcription-polymerase chain reaction showed that 29% of them (14/48) were positive for IL-1beta mRNA. One of the cells that was strongly positive for IL-1beta mRNA had a sibling that generated 366,000 cells of multiple lineages after 14 d. IL-1beta converting enzyme mRNA, which is necessary to produce IL-1beta, was also detected by reverse transcription-polymerase chain reaction at the single-cell level. Moreover, enzyme immunoassay for mature secreted IL-1beta in culture supernatants demonstrated the production of IL-1beta protein by these cells. This was confirmed by fluorescent immunostaining of the cells for human IL-1beta which showed a significant portion of positive cells. Taken together, the results demonstrate the capacity of early hematopoietic cells to synthesize IL-1beta. The capacity of human hematopoietic stem/progenitor cells to produce IL-1beta may be involved in regulation of their proliferation and differentiation under certain circumstances and dysregulation of this process may be modified in leukemogenesis. PMID:8601632

Watari, K; Mayani, H; Lee, F; Dragowska, W; Lansdorp, P M; Schrader, J W

1996-01-01

406

Role of Circulating Osteogenic Progenitor Cells in Calcific Aortic Stenosis  

PubMed Central

Objectives The purpose of this study was to determine the role of circulating endothelial progenitor cells with osteoblastic phenotype (EPC-OCN) in human aortic valve calcification (AVC). Background Recent evidence suggests that rather than passive mineralization, AVC is an active atherosclerotic process with an osteoblastic component resembling coronary calcification. We have recently identified circulating EPCs with osteogenic properties carrying both endothelial progenitor (CD34, KDR) and osteoblastic (osteocalcin [OCN]) cell surface markers. Methods Blood samples from controls (n = 22) and patients with mild to moderate calcific aortic stenosis (mi-moAS, n = 17), severe calcific AS (sAS, n = 26), and both sAS and severe coronary artery disease (sCAD) (n = 33) were collected during diagnostic coronary angiography. By using flow cytometry, peripheral blood mononuclear cells were analyzed for CD34, KDR, and OCN. Resected normal and calcified aortic valves were analyzed histologically. Results Patients with mi-moAS and patients with sAS/sCAD had significantly less EPCs (CD34+/KDR+/OCN?) than controls. Patients with sAS showed significantly higher numbers of EPC-OCN (CD34+/KDR+/OCN+) than controls. In addition, the percentage of EPC costaining for OCN was higher in all disease groups compared with controls. A subgroup analysis of younger patients with bicuspid sAS showed a similar pattern of significantly lower EPCs but a high percentage of coexpression of OCN. Immunofluorescence showed colocalization of nuclear factor kappa-B and OCN in diseased and normal valves. CD34+/OCN+ cells were abundant in the endothelial and deeper cell layers of calcific aortic valve tissue but not in normal aortic valve tissue. Conclusions Circulating EPC-OCN may play a significant role in the pathogenesis and as markers of prognostication of calcific AS. PMID:23062532

Gossl, Mario; Khosla, Sundeep; Zhang, Xin; Higano, Nara; Jordan, Kyra L.; Loeffler, Darrell; Enriquez-Sarano, Maurice; Lennon, Ryan J.; Lerman, Lilach O.; Lerman, Amir

2014-01-01

407

TOWARD REALISTIC PROGENITORS OF CORE-COLLAPSE SUPERNOVAE  

SciTech Connect

Two-dimensional (2D) hydrodynamical simulations of progenitor evolution of a 23 M{sub sun} star, close to core collapse (in {approx}1 hr in one dimension (1D)), with simultaneously active C, Ne, O, and Si burning shells, are presented and contrasted to existing 1D models (which are forced to be quasi-static). Pronounced asymmetries and strong dynamical interactions between shells are seen in 2D. Although instigated by turbulence, the dynamic behavior proceeds to sufficiently large amplitudes that it couples to the nuclear burning. Dramatic growth of low-order modes is seen as well as large deviations from spherical symmetry in the burning shells. The vigorous dynamics is more violent than that seen in earlier burning stages in the three-dimensional (3D) simulations of a single cell in the oxygen burning shell, or in 2D simulations not including an active Si shell. Linear perturbative analysis does not capture the chaotic behavior of turbulence (e.g., strange attractors such as that discovered by Lorenz), and therefore badly underestimates the vigor of the instability. The limitations of 1D and 2D models are discussed in detail. The 2D models, although flawed geometrically, represent a more realistic treatment of the relevant dynamics than existing 1D models, and present a dramatically different view of the stages of evolution prior to collapse. Implications for interpretation of SN1987A, abundances in young supernova remnants, pre-collapse outbursts, progenitor structure, neutron star kicks, and fallback are outlined. While 2D simulations provide new qualitative insight, fully 3D simulations are needed for a quantitative understanding of this stage of stellar evolution. The necessary properties of such simulations are delineated.

David Arnett, W.; Meakin, Casey, E-mail: wdarnett@gmail.com, E-mail: casey.meakin@gmail.com [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)

2011-06-01

408

Supernova Rates, Rise-Times, and their Relations to Progenitors  

NASA Astrophysics Data System (ADS)

Supernovae are fundamental in astronomy: they inject high mass elements into the interstellar medium enriching the chemistry of galaxies, they feed processes of star formation and active galactic nuclei, and they have been a key for the developments in cosmology of the past decades. This dissertation presents a set of subluminous type Ia supernovae (SNe Ia) at z > 0.1 from the Supernova Legacy Survey (SNLS). These faint and short-lived transients are found in massive and passive host galaxies. We measure a volumetric rate as a function of redshift that is different from the normal SN Ia population. The observations point towards a long delay time since the birth of the progenitors systems and argue for progenitor stars of initial low mass. We calculate a stretch-corrected rise-time since explosion to maximum brightness for different sets of SNe Ia. We find that a fiducial 17 day quadratic rise is sufficient to explain all SNe Ia, including subluminous ones, arguing for their homogeneity throughout the entire light-curve. Subluminous SNe Ia are powered by as little as 0.05 solar masses of radioactive nickel synthesized in the explosion. Theoretical models need to explain these challenging weak explosions within the framework of SNe Ia. Finally, we develop one of the first robust automated techniques to identify plateau supernovae (SNe IIP) in large photometric transient surveys. This simple method was tested with a variety of real and simulated SN samples and proved to be effective across different redshifts. Such a photometric typing will be of great power for coming surveys and will allow numerous scientific studies of SNe IIP.

Gonzalez Gaitan, Santiago

409

Proteomic divergence in Arabidopsis autopolyploids and allopolyploids and their progenitors  

PubMed Central

Autopolyploidy and allopolyploidy are common in many plants and some animals. Rapid changes in genomic composition and gene expression have been observed in both autopolyploids and allopolyploids, but the effects of polyploidy on proteomic divergence are poorly understood. Here, we report quantitative analysis of protein changes in leaves of Arabidopsis autopolyploids and allotetraploids and their progenitors using isobaric tags for relative and absolute quantitation (iTRAQ) coupled with mass spectrometry. In more than 1000 proteins analyzed, the levels of protein divergence were relatively high (?18%) between Arabidopsis thaliana and Arabidopsis arenosa, relatively low (?6.8%) between an A. thaliana diploid and autotetraploid and intermediate (?8.3 and 8.2%) in F1- and F8-resynthesized allotetraploids relative to mid-parent values, respectively. This pattern of proteomic divergence was consistent with the previously reported gene expression data. In particular, many non-additively accumulated proteins (61–62%) in the F1 and F8 allotetraploids were also differentially expressed between the parents. The differentially accumulated proteins in functional categories of abiotic and biotic stresses were overrepresented between an A. thaliana autotetraploid and diploid and between two Arabidopsis species, but not significantly different between allotetraploids and their progenitors. Although the trend of changes is similar, the percentage of differentially accumulated proteins that matched previously reported differentially expressed genes was relatively low. Western blot analysis confirmed several selected proteins with isoforms the cumulative levels of which were differentially expressed. These data suggest high protein divergence between species and rapid changes in post-transcriptional regulation and translational modifications of proteins during polyploidization. PMID:22009271

Ng, D W-K; Zhang, C; Miller, M; Shen, Z; Briggs, S P; Chen, Z J

2012-01-01

410

Spontaneous Calcium Oscillations Regulate Human Cardiac Progenitor Cell Growth  

PubMed Central

Rationale The adult heart possesses a pool of progenitor cells stored in myocardial niches but the mechanisms involved in the activation of this cell compartment are currently unknown. Objective Ca2+ promotes cell growth raising the possibility that changes in intracellular Ca2+ initiate division of c-kit-positive human cardiac progenitor cells (hCPCs) and determine their fate. Methods and Results Ca2+ oscillations were identified in hCPCs and these events occurred independently from coupling with cardiomyocytes or the presence of extracellular Ca2+. These findings were confirmed in the heart of transgenic mice in which EGFP was under the control of the c-kit-promoter. Ca2+ oscillations in hCPCs were regulated by the release of Ca2+ from the ER through activation of inositol 1,4,5-triphosphate receptors (IP3Rs) and the re-uptake of Ca2+ by the sarco/endoplasmic reticulum Ca2+ pump (SERCA). IP3Rs and SERCA were highly expressed in hCPCs while ryanodine receptors were not detected. Although Na+-Ca2+ exchanger, store-operated Ca2+-channels and plasma membrane Ca2+-pump were present and functional in hCPCs, they had no direct effects on Ca2+ oscillations. Conversely, Ca2+ oscillations and their frequency markedly increased with ATP and histamine which activated purinoceptors and histamine-1 receptors highly expressed in hCPCs. Importantly, Ca2+ oscillations in hCPCs were coupled with the entry of cells into the cell cycle and BrdUrd incorporation. Induction of Ca2+ oscillations in hCPCs prior to their intramyocardial delivery to infarcted hearts was associated with enhanced engraftment and expansion of these cells promoting the generation of a large myocyte progeny. Conclusion IP3R-mediated Ca2+ mobilization control hCPC growth and their regenerative potential. PMID:19745162

Ferreira-Martins, João; Rondon-Clavo, Carlos; Tugal, Derin; Korn, Justin A; Rizzi, Roberto; Padin-Iruegas, Maria Elena; Ottolenghi, Sergio; De Angelis, Antonella; Urbanek, Konrad; Iwata, Noriko; D’Amario, Domenico; Hosoda, Toru; Leri, Annarosa; Kajstura, Jan; Anversa, Piero; Rota, Marcello

2009-01-01

411

Formation and Evolution of Hypernova Progenitors in Massive Binary Systems  

NASA Astrophysics Data System (ADS)

If long ?-ray bursts are produced by hypernovae, a problem that must be confronted is how the core of the hypernova progenitor retains or acquires sufficient angular momentum to produce the requisite axisymmetric collapse. Physical processes during the evolution of an isolated massive star will tend to extract any initial angular momentum from the stellar core, rendering it difficult for such a star to become a hypernova. However, a substantial fraction of massive stars are members of binary systems. Tidal locking, mass transfer, or stellar merger in an evolved massive binary may lead to the transfer of orbital angular momentum to the core of one of the stars (or the merged star), sufficient to produce the progenitor of a hypernova. We have developed a new binary stellar-evolution code that includes the effects of mass and angular-momentum transfer between the component stars and the subsequent transport of angular momentum through one of the stars. This transport is affected by dynamical and secular shear instabilities, convective motions, the critical layer instability, and gravity waves. Our code treats in a self-consistent way the dynamical distortion of the star resulting from the induced rapid differential rotation. The results of our numerical computations indicate that late main-sequence or early post-mainsequence accretion from a binary companion onto a star with an initial mass ? 20M? may produce a stellar core that is rotating sufficiently rapidly when it collapses to provide the initial conditions necessary for a hypernova event. Our results also indicate that the merger of a late post-main-sequence star with its binary companion, as considered by Ivanova, Podsiadlowski & Spruit (2002), may also lead to a hypernova event in the stellar core but is unlikely to produce an observable ?-ray burst.

Joss, P. C.; Becker, J. A.

412

Comparative gene array analysis of progenitor cells from human paired deep neck and subcutaneous adipose tissue.  

PubMed

Brown and white adipocytes have been shown to derive from different progenitors. In this study we sought to clarify the molecular differences between human brown and white adipocyte progenitors cells. To this end, we performed comparative gene array analysis on progenitor cells isolated from paired biopsies of deep and subcutaneous neck adipose tissue from individuals (n?=?6) undergoing neck surgery. Compared with subcutaneous neck progenitors, cells from the deep neck adipose tissue displayed marked differences in gene expression pattern, including 355 differentially regulated (>1.5 fold) genes. Analysis of highest regulated genes revealed that STMN2, MME, ODZ2, NRN1 and IL13RA2 genes were specifically expressed in white progenitor cells, whereas expression of LRRC17, CNTNAP3, CD34, RGS7BP and ADH1B marked brown progenitor cells. In conclusion, progenitors from deep neck and subcutaneous neck adipose tissue are characterized by a distinct molecular signature, giving rise to either brown or white adipocytes. The newly identified markers may provide potential pharmacological targets facilitating brown adipogenesis. PMID:25102227

Tews, D; Schwar, V; Scheithauer, M; Weber, T; Fromme, T; Klingenspor, M; Barth, T F; Möller, P; Holzmann, K; Debatin, K M; Fischer-Posovszky, P; Wabitsch, M

2014-09-01

413

Dynamic gene expression by putative hair-cell progenitors during regeneration in the zebrafish lateral line.  

PubMed

Hearing loss is most commonly caused by the destruction of mechanosensory hair cells in the ear. This condition is usually permanent: Despite the presence of putative hair-cell progenitors in the cochlea, hair cells are not naturally replenished in adult mammals. Unlike those of the mammalian ear, the progenitor cells of nonmammalian vertebrates can regenerate hair cells throughout life. The basis of this difference remains largely unexplored but may lie in molecular dissimilarities that affect how progenitors respond to hair-cell death. To approach this issue, we analyzed gene expression in hair-cell progenitors of the lateral-line system. We developed a transgenic line of zebrafish that expresses a red fluorescent protein in the presumptive hair-cell progenitors known as mantle cells. Fluorescence-activated cell sorting from the skins of transgenic larvae, followed by microarray-based expression analysis, revealed a constellation of transcripts that are specifically enriched in these cells. Gene expression analysis after hair-cell ablation uncovered a cohort of genes that are differentially regulated early in regeneration, suggesting possible roles in the response of progenitors to hair-cell death. These results provide a resource for studying hair-cell regeneration and the biology of sensory progenitor cells. PMID:24706895

Steiner, Aaron B; Kim, Taeryn; Cabot, Victoria; Hudspeth, A J

2014-04-01

414

Matrix adhesion polarizes heart progenitor induction in the invertebrate chordate Ciona intestinalis  

PubMed Central

Cell-matrix adhesion strongly influences developmental signaling. Resulting impacts on cell migration and tissue morphogenesis are well characterized. However, the in vivo impact of adhesion on fate induction remains ambiguous. Here, we employ the invertebrate chordate Ciona intestinalis to delineate an essential in vivo role for matrix adhesion in heart progenitor induction. In Ciona pre-cardiac founder cells, invasion of the underlying epidermis promotes localized induction of the heart progenitor lineage. We found that these epidermal invasions are associated with matrix adhesion along the pre-cardiac cell/epidermal boundary. Through targeted manipulations of RAP GTPase activity, we were able to manipulate pre-cardiac cell-matrix adhesion. Targeted disruption of pre-cardiac cell-matrix adhesion blocked heart progenitor induction. Conversely, increased matrix adhesion generated expanded induction. We were also able to selectively restore cell-matrix adhesion and heart progenitor induction through targeted expression of Ci-Integrin ?2. These results indicate that matrix adhesion functions as a necessary and sufficient extrinsic cue for regional heart progenitor induction. Furthermore, time-lapse imaging suggests that cytokinesis acts as an intrinsic temporal regulator of heart progenitor adhesion and induction. Our findings highlight a potentially conserved role for matrix adhesion in early steps of vertebrate heart progenitor specification. PMID:23444358

Norton, Jennifer; Cooley, James; Islam, A. F. M. Tariqul; Cota, Christina D.; Davidson, Brad

2013-01-01

415

Perturbation of fetal liver hematopoietic stem and progenitor cell development by trisomy 21  

PubMed Central

The 40-fold increase in childhood megakaryocyte-erythroid and B-cell leukemia in Down syndrome implicates trisomy 21 (T21) in perturbing fetal hematopoiesis. Here, we show that compared with primary disomic controls, primary T21 fetal liver (FL) hematopoietic stem cells (HSC) and megakaryocyte-erythroid progenitors are markedly increased, whereas granulocyte-macrophage progenitors are reduced. Commensurately, HSC and megakaryocyte-erythroid progenitors show higher clonogenicity, with increased megakaryocyte, megakaryocyte-erythroid, and replatable blast colonies. Biased megakaryocyte-erythroid–primed gene expression was detected as early as the HSC compartment. In lymphopoiesis, T21 FL lymphoid-primed multipotential progenitors and early lymphoid progenitor numbers are maintained, but there was a 10-fold reduction in committed PreproB-lymphoid progenitors and the functional B-cell potential of HSC and early lymphoid progenitor is severely impaired, in tandem with reduced early lymphoid gene expression. The same pattern was seen in all T21 FL samples and no samples had GATA1 mutations. Therefore, T21 itself causes multiple distinct defects in FL myelo- and lymphopoiesis. PMID:23045701

Roy, Anindita; Cowan, Gillian; Mead, Adam J.; Filippi, Sarah; Bohn, Georg; Chaidos, Aristeidis; Tunstall, Oliver; Chan, Jerry K. Y.; Choolani, Mahesh; Bennett, Phillip; Kumar, Sailesh; Atkinson, Deborah; Wyatt-Ashmead, Josephine; Hu, Ming; Stumpf, Michael P. H.; Goudevenou, Katerina; O'Connor, David; Chou, Stella T.; Weiss, Mitchell J.; Karadimitris, Anastasios; Jacobsen, Sten Eirik; Vyas, Paresh; Roberts, Irene

2012-01-01

416

Lhx2 specifies regional fate in Emx1 lineage of telencephalic progenitors generating cerebral cortex  

PubMed Central

Cerebral cortex is comprised of regions including six-layer neocortex and three-layer olfactory cortex generated by telencephalic progenitors of an Emx1 lineage. The mechanism specifying region-specific subpopulations within this lineage is unknown. We show in mouse that the LIM homeodomain transcription factor Lhx2, expressed in graded levels by progenitors, determines their regional identity and fate decisions to generate neocortex or olfactory cortex. Emx1-Cre deletion of Lhx2 at E10.5 refates progenitors to generate three-layer cortex phenocopying olfactory cortex rather than lateral neocortex. Progenitors do not generate ectopic olfactory cortex following Lhx2 deletion at E11.5. Thus, Lhx2 regulates a regional-fate decision by telencephalic progenitors during a critical period that closes as they differentiate from neuroepithelial cells to neuronogenic radial glia. “Exposure” of progenitors to Lhx2 may dictate their regional-fate decisions. These findings establish a genetic mechanism determining regional fate in the Emx1 lineage of telencephalic progenitors that generate cerebral cortex. PMID:19820705

Chou, Shen-Ju; Perez-Garcia, Carlos G.; Kroll, Todd T.; O'Leary, Dennis D.M.

2009-01-01

417

Dynamic gene expression by putative hair-cell progenitors during regeneration in the zebrafish lateral line  

PubMed Central

Hearing loss is most commonly caused by the destruction of mechanosensory hair cells in the ear. This condition is usually permanent: Despite the presence of putative hair-cell progenitors in the cochlea, hair cells are not naturally replenished in adult mammals. Unlike those of the mammalian ear, the progenitor cells of nonmammalian vertebrates can regenerate hair cells throughout life. The basis of this difference remains largely unexplored but may lie in molecular dissimilarities that affect how progenitors respond to hair-cell death. To approach this issue, we analyzed gene expression in hair-cell progenitors of the lateral-line system. We developed a transgenic line of zebrafish that expresses a red fluorescent protein in the presumptive hair-cell progenitors known as mantle cells. Fluorescence-activated cell sorting from the skins of transgenic larvae, followed by microarray-based expression analysis, revealed a constellation of transcripts that are specifically enriched in these cells. Gene expression analysis after hair-cell ablation uncovered a cohort of genes that are differentially regulated early in regeneration, suggesting possible roles in the response of progenitors to hair-cell death. These results provide a resource for studying hair-cell regeneration and the biology of sensory progenitor cells. PMID:24706895

Kim, Taeryn; Cabot, Victoria; Hudspeth, A. J.

2014-01-01

418

Targeting of c-kit+ haematopoietic progenitor cells prevents hypoxic pulmonary hypertension.  

PubMed

Haematopoietic c-kit+ progenitor cells may contribute to pulmonary vascular remodelling and pulmonary hypertension (PH). Stromal derived factor-1 (SDF-1/CXCL12) and its receptors CXCR4 and CXCR7 have been shown to be critical for homing and mobilisation of haematopoietic c-kit+ progenitor cells in the perivascular niche. We administered AMD3100, a CXCR4 antagonist, and CCX771, a CXCR7 antagonist, to chronic hypoxia exposed mice in order to study the role of c-kit+ progenitor cells in PH. CXCL12, CXCR4 and CXCR7 protein expression, haemodynamic parameters, right ventricular mass, extent of vascular remodelling and perivascular progenitor cell accumulation were studied. Chronic hypoxia-exposed mice showed increased total lung tissue expression of CXCR4, CXCR7 and CXCL12 after development of PH. This was associated with significantly increased right ventricular systolic pressure and evidence of right ventricular hypertrophy, vascular remodelling and perivascular c-kit+/sca-1+ progenitor cell accumulation. CCX771 administration did not abrogate these effects. In contrast, administration of AMD3100, whether alone or combined with CCX771, prevented vascular remodelling, PH and perivascular accumulation of c-kit+/sca-1+ progenitor cells, with a synergistic effect of these agents. This study offers important pathophysiological insights into the role of haematopoietic c-kit+ progenitors in hypoxia-induced vascular remodelling and may have therapeutic implications for PH. PMID:20884740

Gambaryan, N; Perros, F; Montani, D; Cohen-Kaminsky, S; Mazmanian, M; Renaud, J-F; Simonneau, G; Lombet, A; Humbert, M

2011-06-01

419

Generation of both cortical and Aire+ medullary thymic epithelial compartments from CD205+ progenitors  

PubMed Central

In the adult thymus, the development of self-tolerant thymocytes requires interactions with thymic epithelial cells (TECs). Although both cortical and medullary TECs (cTECs/mTECs) are known to arise from common bipotent TEC progenitors, the phenotype of these progenitors and the timing of the emergence of these distinct lineages remain unclear. Here, we have investigated the phenotype and developmental properties of bipotent TEC progenitors during cTEC/mTEC lineage development. We show that TEC progenitors can undergo a stepwise acquisition of first cTEC and then mTEC hallmarks, resulting in the emergence of a progenitor population simultaneously expressing the cTEC marker CD205 and the mTEC regulator Receptor Activator of NF-?B (RANK). In vivo analysis reveals the capacity of CD205+ TECs to generate functionally competent cortical and medullary microenvironments containing both cTECs and Aire+ mTECs. Thus, TEC development involves a stage in which bipotent progenitors can co-express hallmarks of the cTEC and mTEC lineages through sequential acquisition, arguing against a simple binary model in which both lineages diverge simultaneously from bipotent lineage negative TEC progenitors. Rather, our data reveal an unexpected overlap in the phenotypic properties of these bipotent TECs with their lineage-restricted counterparts. PMID:23299414

Baik, Song; Jenkinson, Eric J; Lane, Peter J L; Anderson, Graham; Jenkinson, William E

2013-01-01

420

Isolation of primitive endoderm, mesoderm, vascular endothelial and trophoblast progenitors from human pluripotent stem cells  

PubMed Central

To identify early populations of committed progenitors derived from human embryonic stem cells (hESCs), we screened self-renewing, BMP4-treated and retinoic acid–treated cultures with >400 antibodies recognizing cell-surface antigens. Sorting of >30 subpopulations followed by transcriptional analysis of developmental genes identified four distinct candidate progenitor groups. Subsets detected in self-renewing cultures, including CXCR4+ cells, expressed primitive endoderm genes. Expression of Cxcr4 in primitive endoderm was confirmed in visceral endoderm of mouse embryos. BMP4-induced progenitors exhibited gene signatures of mesoderm, trophoblast and vascular endothelium, suggesting correspondence to gastrulation-stage primitive streak, chorion and allantois precursors, respectively. Functional studies in vitro and in vivo confirmed that ROR2+ cells produce mesoderm progeny, APA+ cells generate syncytiotrophoblasts and CD87+ cells give rise to vasculature. The same progenitor classes emerged during the differentiation of human induced pluripotent stem cells (hiPSCs). These markers and progenitors provide tools for purifying human tissue-regenerating progenitors and for studying the commitment of pluripotent stem cells to lineage progenitors. PMID:22634564

Drukker, Micha; Tang, Chad; Ardehali, Reza; Rinkevich, Yuval; Seita, Jun; Lee, Andrew S.; Mosley, Adriane R.; Weissman, Irving L.; Soen, Yoav

2013-01-01