Different patterns of rDNA organization at interphase in nuclei of wheat and rye

1992 ◽  
Vol 101 (4) ◽  
pp. 751-757 ◽  
Author(s):  
A.R. Leitch ◽  
W. Mosgoller ◽  
M. Shi ◽  
J.S. Heslop-Harrison
Keyword(s):  
Light And Electron Microscopy ◽  
Intergenic Spacer ◽  
Triticum Aestivum L ◽  
Rrna Genes ◽  
Root Tip ◽  
Rdna Sequences ◽  
Secale Cereale L ◽  
Rdna Organization ◽  
Active Nors

The physical location of the rDNA repeating units (25 S, 18 S and 5.8 S rRNA genes and the intergenic spacer sequences) was investigated in rye (Secale cereale L.) and wheat (Triticum aestivum L.) root tip meristematic cells by in situ hybridization using light and electron microscopy. The rDNA sequences are organized differently in the two related and intercrossable species. In rye (2n = 14, one pair of chromosomes with nucleolar organizing regions, NORs), two condensed blocks of rDNA-containing chromatin occurred in each interphase nucleus. The blocks were associated with the periphery of nucleoli and a single-labelled, decondensed rDNA fibre extended into the nucleolus from the block. We term this expression pattern terminal decondensation. In wheat (2n = 6x = 42, five pairs of chromosomes with NORs), inactive condensed labelled chromatin was found unassociated with nucleoli. Active NORs had some condensed rDNA associated with the nucleolar periphery, but, in contrast to rye, condensed rDNA was also found within the nucleolus. The condensed labelled rDNA in wheat nucleoli was visible as fluorescent foci in the light microscope and labelled condensed chromatin in the electron microscope. Its absence in rye shows that condensed rDNA need not be present in active plant nucleoli. Diffuse labelled sites of rDNA, likely to represent actively transcribed rDNA, were found in both rye and wheat. Active rDNA loci in wheat have many expressed segments separated by unexpressed, condensed, rDNA-fragmented decondensation-while each locus in rye has a single, unexpressed perinucleolar condensed block of rRNA genes. Thus the positions of actively transcribed genes within the tandem arrays of rDNA at each locus are fundamentally different in the two cereals. The NOR chromosome appeared to extend through the nucleolus, and active rDNA sequences did not loop out from chromatin into the nucleolus as is frequently described in nucleolar models.

THE INHERITANCE OF RYE CHROMOSOMES IN EARLY GENERATIONS OF TRITICALE × WHEAT HYBRIDS

1982 ◽  
Vol 24 (3) ◽  
pp. 285-291 ◽  
Author(s):  
C. E. May ◽  
R. Appels
Keyword(s):  
Triticum Aestivum ◽  
Secale Cereale ◽  
Second Generation ◽  
Triticum Aestivum L ◽  
Chromosome Translocation ◽  
Agronomic Characters ◽  
Secale Cereale L ◽  
Wheat Hybrids ◽  
Triticosecale Wittmack

Triticales (× Triticosecale Wittmack) are being employed as a source of rye (Secale cereale L.) chromatin for the introduction of specific agronomic characters into wheat (Triticum aestivum L. em Thell.). The rye chromosomes present in plants of the first and second generations of a backcrossing program have been identified using a radioactive in situ probe which hybridizes to specific sites on the rye chromosomes. We show that homologous pairs of rye chromosomes are present by the second generation which should thereby ensure their eventual substitution. Furthermore, rye telosomes and a wheat-rye chromosome translocation involving 5RL were also observed as possibly useful modifications of the rye chromosomes in this breeding program.

Limitations of the widely used GAM42a and BET42a probes targeting bacteria in the Gammaproteobacteria radiation

Microbiology ◽  
2003 ◽  
Vol 149 (5) ◽  
pp. 1239-1247 ◽  
Author(s):  
Christine Yeates ◽  
Aaron M. Saunders ◽  
Gregory R. Crocetti ◽  
Linda L. Blackall
Keyword(s):  
Intergenic Spacer ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
23S Rrna ◽  
Target Region ◽  
Intergenic Spacer Region ◽  
Probe Target ◽  
Pcr Products ◽  
23S Rrna Genes

The 23S rRNA-targeted probes GAM42a and BET42a provided equivocal results with the uncultured gammaproteobacterium ‘Candidatus Competibacter phosphatis' where some cells bound GAM42a and other cells bound BET42a in fluorescence in situ hybridization (FISH) experiments. Probes GAM42a and BET42a span positions 1027–1043 in the 23S rRNA and differ from each other by one nucleotide at position 1033. Clone libraries were prepared from PCR products spanning the 16S rRNA genes, intergenic spacer region and 23S rRNA genes from two mixed cultures enriched in ‘Candidatus C. phosphatis’. With individual clone inserts, the 16S rDNA portion was used to confirm the source organism as ‘Candidatus C. phosphatis' and the 23S rDNA portion was used to determine the sequence of the GAM42a/BET42a probe target region. Of the 19 clones sequenced, 8 had the GAM42a probe target (T at position 1033) and 11 had G at position 1033, the only mismatch with GAM42a. However, none of the clones had the BET42a probe target (A at 1033). Non-canonical base-pairing between the 23S rRNA of ‘Candidatus C. phosphatis' with G at position 1033 and GAM42a (G–A) or BET42a (G–T) is likely to explain the probing anomalies. A probe (GAM42_C1033) was optimized for use in FISH, targeting cells with G at position 1033, and was found to highlight not only some ‘Candidatus C. phosphatis' cells, but also other bacteria. This demonstrates that there are bacteria in addition to ‘Candidatus C. phosphatis' with the GAM42_C1033 probe target and not the BET42a or GAM42a probe target.

Chromosomal localization and polymorphisms of ribosomal DNA in oat (Avena spp.)

Genome ◽  
1994 ◽  
Vol 37 (1) ◽  
pp. 23-32 ◽  
Author(s):  
E. N. Jellen ◽  
R. L. Phillips ◽  
H. W. Rines
Keyword(s):  
In Situ Hybridization ◽  
Ribosomal Dna ◽  
Intergenic Spacer ◽  
Ecori Fragment ◽  
Rdna Sequences ◽  
Restriction Sites ◽  
Rdna Variation ◽  
Rdna Polymorphisms ◽  
Sat 1

The 17S/5.8S/26S ribosomal DNA (rDNA) sequences were mapped to the three satellited (SAT) chromosomes in the common hexaploid cultivated oat Avena sativa (2n = 6x = 42, AACCDD genomes). In situ hybridization and Southern hybridization of maize and (or) wheat rDNA probes to DNA from nullisomics derived from the cultivar 'Sun II' allowed the placement of rDNA sequences to the physical chromosomes. A restriction map was produced for the rDNA sequences of 'Sun II' using a maize probe from the transcribed region of the 17S/26S rDNA repeat. The set of rDNA repeats on SAT 2 of 'Sun II' possesses a 10.5-kb EcoRI fragment not found in the rDNA repeats of SAT 1 and SAT 8. This 10.5-kb fragment results from the absence of an EcoRI site in the intergenic spacer (IGS) of SAT 2 repeats. Extensive polymorphisms were demonstrated for three hexaploid Avena species, namely, the Mediterranean-type cultivated oat A. byzantina and the wild species A. sterilis and A. fatua. However, geographically diverse A. sativa cultivars displayed little rDNA variation. In contrast with all of the A. sativa cultivars examined, the A. sterilis accessions generally lacked the 10.5-kb EcoRI fragment. The results support the hypothesis that A. sativa accessions descend from a limited ancestral cultivated population. The rDNA polymorphisms are attributed to differences in lengths and restriction sites of the IGS.Key words: oats, rDNA, RFLPs, nullisomics, in situ hybridization.

Physical mapping of the 5S rRNA multigene family in 6x triticale and rye: identification of a new rye locus

Genome ◽  
1995 ◽  
Vol 38 (3) ◽  
pp. 623-626 ◽  
Author(s):  
Angeles Cuadrado ◽  
Nicolas Jouv ◽  
J. S. Heslop-Harrison
Keyword(s):  
In Situ Hybridization ◽  
Multigene Family ◽  
The Other ◽  
5S Rrna ◽  
Rrna Genes ◽  
Hexaploid Triticale ◽  
Selected Lines ◽  
Secale Cereale L ◽  
5S Rrna Genes

In situ hybridization was used to physically map the 5S rRNA multigene family in three selected lines of hexaploid triticale and five lines of diploid rye. Using this technique, evidence for a new locus on the 3RS arm of the three triticale lines was first obtained, as well as confirmation of the presence of 5S rRNA loci on wheat and rye chromosomes of homoeologous groups 1 and 5. The new locus on the 3RS arm was confirmed in two lines of rye, Secale cereale L., although it was not present in the other rye varieties studied. We propose that the new 5S rRNA locus be referred to as 5SDna-R3.Key words: in situ hybridization, FISH, Secale, triticale, 5S rRNA genes.

mRNA localization by Electron microscopic in situ hybridization

1991 ◽  
Vol 49 ◽  
pp. 430-431
Author(s):  
J. A. Pollock ◽  
M. Martone ◽  
T. Deerinck ◽  
M. H. Ellisman
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Nucleic Acids ◽  
Recombinant Dna ◽  
Light And Electron Microscopy ◽  
Electron Microscopic ◽  
High Voltage Electron Microscopy ◽  
Functional Sites ◽  
Voltage Electron

Localization of specific proteins in cells by both light and electron microscopy has been facilitate by the availability of antibodies that recognize unique features of these proteins. High resolution localization studies conducted over the last 25 years have allowed biologists to study the synthesis, translocation and ultimate functional sites for many important classes of proteins. Recently, recombinant DNA techniques in molecular biology have allowed the production of specific probes for localization of nucleic acids by “in situ” hybridization. The availability of these probes potentially opens a new set of questions to experimental investigation regarding the subcellular distribution of specific DNA's and RNA's. Nucleic acids have a much lower “copy number” per cell than a typical protein, ranging from one copy to perhaps several thousand. Therefore, sensitive, high resolution techniques are required. There are several reasons why Intermediate Voltage Electron Microscopy (IVEM) and High Voltage Electron Microscopy (HVEM) are most useful for localization of nucleic acids in situ.

scholarly journals Remodeling of root morphology by CuO and ZnO nanoparticles: effects on drought tolerance for plants colonized by a beneficial pseudomonad

Botany ◽  
2018 ◽  
Vol 96 (3) ◽  
pp. 175-186 ◽  
Author(s):  
Kwang-Yeol Yang ◽  
Stephanie Doxey ◽  
Joan E. McLean ◽  
David Britt ◽  
Andre Watson ◽  
...  
Keyword(s):  
Calcareous Soils ◽  
Root Hairs ◽  
Triticum Aestivum L ◽  
Metal Stress ◽  
Root Tip ◽  
Zno Nps ◽  
Wheat Seedlings ◽  
Cuo Nps ◽  
Expression Of Genes ◽  
Induced Tolerance

Formulations that include nanoparticles of CuO and ZnO are being considered for agricultural applications as fertilizers because they act as sources of Cu or Zn. Currently, few studies of the effects of these nanoparticles (NPs) consider the three-way interactions of NPs with the plant plus its microbiome. At doses that produced root shortening by both nanoparticles (NPs), CuO NPs induced the proliferation of elongated root hairs close to the root tip, and ZnO NPs increased lateral root formation in wheat seedlings (Triticum aestivum L.). These responses occurred with roots colonized by a beneficial bacterium, Pseudomonas chlororaphis O6 (PcO6), originally isolated from roots of wheat grown under dryland farming in calcareous soils. The PcO6-induced tolerance to drought stress in wheat seedlings was not impaired by the NPs. Rather, growth of the PcO6-colonized plants with NPs resulted in systemic increases in the expression of genes associated with tolerance to water stress. Increased expression in the shoots of other genes related to metal stress was consistent with higher levels of Cu and Zn in PcO6-colonized shoots grown with the NPs. This work demonstrates that plants grown with CuO or ZnO NPs showed cross-protection from different challenges such as metal stress and drought.

scholarly journals Highly-Efficient Release of Ferulic Acid from Agro-Industrial By-Products via Enzymatic Hydrolysis with Cellulose-Degrading Enzymes: Part I–The Superiority of Hydrolytic Enzymes Versus Conventional Hydrolysis

Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 782
Author(s):  
Karina Juhnevica-Radenkova ◽  
Jorens Kviesis ◽  
Diego A. Moreno ◽  
Dalija Seglina ◽  
Fernando Vallejo ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Ferulic Acid ◽  
Hydrolytic Enzymes ◽  
Structural Complexity ◽  
Triticum Aestivum L ◽  
Feed Supplement ◽  
Degrading Enzymes ◽  
Secale Cereale L ◽  
Pre Treatment ◽  
By Products

Historically Triticum aestívum L. and Secale cereále L. are widely used in the production of bakery products. From the total volume of grain cultivated, roughly 85% is used for the manufacturing of flour, while the remaining part is discarded or utilized rather inefficiently. The limited value attached to bran is associated with their structural complexity, i.e., the presence of cellulose, hemicellulose, and lignin, which makes this material suitable mostly as a feed supplement, while in food production its use presents a challenge. To valorize these materials to food and pharmaceutical applications, additional pre-treatment is required. In the present study, an effective, sustainable, and eco-friendly approach to ferulic acid (FA) production was demonstrated through the biorefining process accomplished by non-starch polysaccharides degrading enzymes. Up to 11.3 and 8.6 g kg−1 of FA was released from rye and wheat bran upon 24 h enzymatic hydrolysis with multi-enzyme complex Viscozyme® L, respectively.

scholarly journals Microbiological and Geochemical Heterogeneity in an In Situ Uranium Bioremediation Field Site

2005 ◽  
Vol 71 (10) ◽  
pp. 6308-6318 ◽  
Author(s):  
Helen A. Vrionis ◽  
Robert T. Anderson ◽  
Irene Ortiz-Bernad ◽  
Kathleen R. O'Neill ◽  
Charles T. Resch ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Acid Volatile Sulfide ◽  
Rrna Gene ◽  
Gene Sequences ◽  
16S Rrna Gene Sequences ◽  
Geochemical Heterogeneity

ABSTRACT The geochemistry and microbiology of a uranium-contaminated subsurface environment that had undergone two seasons of acetate addition to stimulate microbial U(VI) reduction was examined. There were distinct horizontal and vertical geochemical gradients that could be attributed in large part to the manner in which acetate was distributed in the aquifer, with more reduction of Fe(III) and sulfate occurring at greater depths and closer to the point of acetate injection. Clone libraries of 16S rRNA genes derived from sediments and groundwater indicated an enrichment of sulfate-reducing bacteria in the order Desulfobacterales in sediment and groundwater samples. These samples were collected nearest the injection gallery where microbially reducible Fe(III) oxides were highly depleted, groundwater sulfate concentrations were low, and increases in acid volatile sulfide were observed in the sediment. Further down-gradient, metal-reducing conditions were present as indicated by intermediate Fe(II)/Fe(total) ratios, lower acid volatile sulfide values, and increased abundance of 16S rRNA gene sequences belonging to the dissimilatory Fe(III)- and U(VI)-reducing family Geobacteraceae. Maximal Fe(III) and U(VI) reduction correlated with maximal recovery of Geobacteraceae 16S rRNA gene sequences in both groundwater and sediment; however, the sites at which these maxima occurred were spatially separated within the aquifer. The substantial microbial and geochemical heterogeneity at this site demonstrates that attempts should be made to deliver acetate in a more uniform manner and that closely spaced sampling intervals, horizontally and vertically, in both sediment and groundwater are necessary in order to obtain a more in-depth understanding of microbial processes and the relative contribution of attached and planktonic populations to in situ uranium bioremediation.

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