Searching for telomeric sequences in two Allium species

Genome ◽  
2001 ◽  
Vol 44 (4) ◽  
pp. 640-643 ◽  
Author(s):  
N Cuñado ◽  
E Sánchez-Morán ◽  
J Barrios ◽  
J L Santos
Keyword(s):  
In Situ Hybridization ◽  
Dna Sequences ◽  
Fluorescent In Situ Hybridization ◽  
Two Dimensional ◽  
Ltr Retrotransposons ◽  
Allium Species ◽  
Telomeric Sequences ◽  
Rdna Sequences ◽  
Dimensional Surface

Some Alliaceae species have no tandemly repeated TTTAGGG sequences. Instead, at the very end of their chromosomes, there are highly repetitive satellite and (or) rDNA sequences. These sequences apparently replace the canonical plant telomeric sequences in these species. A method of preparing two-dimensional surface spreads of plant synaptonemal complexes (SCs), combined with fluorescent in situ hybridization, has revealed that telomeric chromatin is tightly condensed at the ends of SCs in plants and animals. Using this method, we have tested the organization and location of those sequences postulated to cap the chromosomes in two species of the genus Allium: A. cepa and A. altaicum. We have also extended this study to other putative telomere candidates, such as LTR (long terminal repeat) and non-LTR retrotransposons. None of the DNA sequences analyzed showed the characteristic telomeric organization at pachytene.Key words: fluorescent in situ hybridization, meiosis, repetitive DNA, Allium, synaptonemal complex.

A molecular analysis of the origin of the Crepis capillaris B chromosome

1994 ◽  
Vol 107 (3) ◽  
pp. 703-708 ◽  
Author(s):  
M. Jamilena ◽  
C. Ruiz Rejon ◽  
M. Ruiz Rejon
Keyword(s):  
In Situ Hybridization ◽  
Dna Sequences ◽  
Repetitive Sequences ◽  
B Chromosome ◽  
Dna Probes ◽  
Telomeric Repeats ◽  
Crepis Capillaris ◽  
Telomeric Sequences ◽  
Hybridization Data

The origin of the B chromosome of Crepis capillaris has been studied by using in situ hybridization with different DNA probes. Genomic in situ hybridization (GISH) with DNA from plants with and without Bs as probes indicates that the B chromosome has many DNA sequences in common with A chromosomes, showing no region rich in B-specific sequences. Six additional DNA probes were used to test the possible origin of this B from the standard NOR chromosome (chromosome 3). In the short arm of the NOR chromosome, we detected not only 18 S + 25 S rDNA, but also 5 S rDNA and a specific repetitive sequence from the NOR chromosome (pCcH32); in the heterochromatic bands of the long arm, we found two different repetitive sequences (pCcE9 and pCcD29). In the B chromosome, however, only the 18 S + 25 S rDNA and the telomeric sequences from Arabidopsis thaliana were observed. Our in situ hybridization data with telomeric repeats indicate that the two telomeres of the B are larger than those of the A chromosomes, confirming the isochromosomal nature of this B. Hybridizations of 18 S + 25 S rDNA and telomeric repeats to blots of DNA from plants with and without Bs reveal a high homology between A and B 18 S + 25 S rDNA genes, but some sequence dissimilarities between A and B telomeres. Taken as a whole, these data indicate that the entire B of C. capillaris, although possibly having originated from the standard genome, did not derive directly from the NOR chromosome.

Organization of highly repeated sequences in surface-spread pachytene chromosomes of rye

Genome ◽  
2000 ◽  
Vol 43 (6) ◽  
pp. 945-948 ◽  
Author(s):  
N Cuñado ◽  
J Barrios ◽  
J L Santos
Keyword(s):  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Repetitive Dna ◽  
Dna Sequences ◽  
Repeated Dna ◽  
Telomeric Sequences ◽  
Different Types ◽  
Surface Spread ◽  
Fish Signal

A method of preparing two-dimensional surface spreads of plant synaptonemal complexes (SCs) associated with fluorescence in situ hybridization (FISH) has been applied to analyze the location and organization of five different highly repeated DNA sequences in rye. Our observations indicate that, depending on the type of sequence, the chromatin displays different types of organization. Telomeric sequences were seen tightly associated with the SC while other repetitive DNA sequences were found to form loops that are associated with SCs only at their bases. On the contrary, the FISH signal of a centromeric satellite had a granular appearance, reflecting that the hybridization occurs only with parts of the chromatin loops.Key words: fluorescence in situ hybridization, meiosis, repetitive DNA, rye, synaptonemal complex.

Fluorescent in situ hybridization with arbitrarily amplified DNA fragments differentiates carrot (Daucus carota L.) chromosomes

Genome ◽  
2012 ◽  
Vol 55 (3) ◽  
pp. 205-213 ◽  
Author(s):  
Anna Nowicka ◽  
Ewa Grzebelus ◽  
Dariusz Grzebelus
Keyword(s):  
In Situ Hybridization ◽  
Daucus Carota ◽  
Fluorescent In Situ Hybridization ◽  
Ltr Retrotransposons ◽  
Chromosome Identification ◽  
Daucus Carota L ◽  
Poorly Differentiated ◽  
End Sequences ◽  
Size And Morphology

Carrot ( Daucus carota L.) chromosomes are small and poorly differentiated in size and morphology. Here we demonstrate that fluorescent in situ hybridization (FISH) signals derived from arbitrary PCR probes can be used for chromosome identification in carrot. To prepare probes, we searched for nonpolymorphic products abundantly amplified with arbitrary decamer primers in a group of accessions representing carrot genetic diversity. As a result, 13 fragments ranging in size from 517 to 1758 bp were selected, sequenced, and used as probes for fluorescent in situ hybridization. Four of these probes produced clear and reproducible hybridization signals. The sequences showed similarity to a number of carrot BAC-end sequences, indicating their repetitive character. Three of them were similar to internal portions of gypsy and copia LTR retrotransposons previously identified in plants. Hybridization signals for the four probes were observed as dotted tracks on chromosomes, differing in distribution and intensity. Generally, they were present in pericentromeric and (or) interstitial localizations on chromosome arms. The use of the four probes allowed discrimination of chromosome pairs and construction of more detailed karyotypes and idiograms of carrot.

scholarly journals Detection of Methanobrevobacter smithii and Methanobrevibacter oralis in Lower Respiratory Tract Microbiota

2020 ◽  
Vol 8 (12) ◽  
pp. 1866
Author(s):  
Yasmine Hassani ◽  
Fabienne Brégeon ◽  
Gérard Aboudharam ◽  
Michel Drancourt ◽  
Ghiles Grine
Keyword(s):  
In Situ Hybridization ◽  
Respiratory Tract ◽  
Bronchoalveolar Lavage ◽  
Dna Sequences ◽  
Lower Respiratory Tract ◽  
Fluorescent In Situ Hybridization ◽  
Opportunistic Pathogens ◽  
Lavage Sample ◽  
Prospective Investigation

Methanogens, the sole microbes producing methane, are archaea commonly found in human anaerobic microbiota. Methanogens are emerging as opportunistic pathogens associated with dysbiosis and are also detected and cultured in anaerobic abscesses. Their presence in the respiratory tract is yet unknown. As a preliminary answer, prospective investigation of 908 respiratory tract samples using polyphasic approach combining PCR-sequencing, real-time PCR, fluorescent in situ hybridization (FISH), and methanogens culture was carried out. Methanobrevibacter smithii and Methanobrevibacter oralis DNA sequences, were detected in 21/527 (3.9%) sputum samples, 2/188 (1.06%) bronchoalveolar lavages, and none of 193 tracheo-bronchial aspirations. Further, fluorescence in situ hybridization detected methanogens in three sputum investigated specimens with stick morphology suggesting M. oralis and in another one bronchoalveolar lavage sample investigated, diplococal morphology suggesting M. smithii. These observations extend the known territory of methanogens to the respiratory tract and lay the foundations for further interpretation of their detection as pathogens in any future cases of isolation from bronchoalveolar lavages and the lungs.

Identification and chromosomal location of a new tandemly repeated DNA in maize

Genome ◽  
2000 ◽  
Vol 43 (1) ◽  
pp. 181-184 ◽  
Author(s):  
Chunxian Chen ◽  
Huihuang Yan ◽  
Wenxue Zhai ◽  
Lihuang Zhu ◽  
Jingsan Sun
Keyword(s):  
In Situ Hybridization ◽  
Dna Sequences ◽  
Fluorescent In Situ Hybridization ◽  
Methylation Pattern ◽  
Repeated Dna ◽  
Dna Library ◽  
New Family ◽  
Genomic Dna Library ◽  
Tandemly Repeated Dna

Two clones of a new family of tandemly repeated DNA sequences have been isolated from a maize random genomic DNA library. MR68 is 410 bp, representing a monomeric unit and MR77 is 1222 bp, containing three units. The copy number was estimated to be about 3000 per 1C maize genome. Its methylation pattern was also determined. Fluorescent in situ hybridization (FISH) indicates that the sequence is located on the subtelomeric region of the long arm of chromosomes 3 and 6, as well as on the satellite of chromosome 6. Key words: Zea mays, tandemly repeated DNA, satellite DNA, fluorescent in situ hybridization (FISH).

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