Pulsed-field gel electrophoresis analysis of the phaseolin locus region in Phaseolus vulgaris

Genome ◽  
1996 ◽  
Vol 39 (4) ◽  
pp. 722-729 ◽  
Author(s):  
Víctor Llaca ◽  
Paul Gepts

Phaseolin is the major seed storage protein of common bean (Phaseolus vulgaris L.). It is encoded by a small multigene family of 6–9 genes that are clustered in a single complex locus (Phs). We have constructed a long-range restriction map of the phaseolin genomic region, including the Phs locus and two flanking marker loci, D1861 and Bng060. Using a combination of high molecular weight DNA isolation, one- and two-dimensional pulsed-field gel electrophoresis of single and double restriction digests followed by Southern hybridization, and PCR analysis of individual fragments, we found that: (i) the maximum size of the Phs locus is 190 kb, (ii) the Phs locus may have increased in size during the evolution of P. vulgaris, (iii) the genomic region marked by D1861–Phs–Bng060 spans 5 cM, which corresponds to a maximum of 1.9 Mb, and (iv) the Phs locus could be oriented with respect to the two adjacent markers. Further progress in determining the gene arrangement in the Phs locus will require cloning and analysis of large DNA fragments containing phaseolin genes via BAC libraries. Key words : multigene family, physical distance, genome mapping, seed protein.

Genome ◽  
1997 ◽  
Vol 40 (6) ◽  
pp. 896-902 ◽  
Author(s):  
Michael Kleine ◽  
Christian Jung ◽  
Wolfgang Michalek ◽  
Thomas Diefenthal ◽  
Harald Dargatz

We describe the construction of a specific yeast artificial chromosome (YAC) library from barley (Hordeum vulgare L.) using the vector pYAC-RC. The library was generated by total digestion of high molecular weight DNA with the infrequently cutting restriction enzyme MluI. Only 10–30% of the colonies were recombinant, as visualized by red–white selection and subsequent pulsed-field gel electrophoresis analysis. About 17 000 individual recombinant YAC clones with insert sizes ranging from 50 to 700 kb, with a mean of 170 kb, were selected. No chloroplast sequences were detected and the proportion of YAC clones containing BARE–1 copia–like retroelements is about 5%. Screening of the library with a single-copy RFLP marker closely linked to the Mla locus yielded three identical clones of the same size. Insert termini of randomly chosen YAC clones were investigated with respect to their redundancy in the barley genome and compared with termini of YAC clones from an EcoRI-based YAC library, resulting in a fourfold enrichment of single-copy sequences at the MluI vector–insert junctions.Key words: yeast artificial chromosomes, YAC, Hordeum vulgare, pulsed-field gel electrophoresis.


1999 ◽  
Vol 37 (6) ◽  
pp. 1892-1898 ◽  
Author(s):  
Karine Rolland ◽  
Corinne Marois ◽  
Veronique Siquier ◽  
Blandine Cattier ◽  
Roland Quentin

A collection of 114 independent Streptococcus agalactiae strains, including 54 strains isolated from the cerebrospinal fluid (CSF) samples of neonates and 60 strains from asymptomatic patients, was characterized by pulsed-field gel electrophoresis (PFGE) of DNA restricted with SmaI and by PCR analysis of the hylB gene. All strains were previously studied by multilocus enzyme electrophoresis (MLEE) (R. Quentin, H. Huet, F.-S. Wang, P. Geslin, A. Goudeau, and R. K. Selander, J. Clin. Microbiol. 33:2576–2581, 1995). Among these 114 strains, there were 92 PFGE patterns. Eleven genetic groups (A to K) were identified with 38% divergence. A more homogeneous group (PFGE group A) was defined, consisting of 73% of the strains previously identified as belonging to a particular MLEE phylogenetic group. A 162-kb fragment was identified as a marker of strains that invaded the central nervous system of neonates. It was detected in 69% of the PFGE patterns obtained with CSF isolates and in only 1.8% of the PFGE patterns obtained with carrier strains. The hylB gene encoding hyaluronate lyase was amplified for all strains in our collection. Ten of 15 isolates belonging to an MLEE subgroup, previously described as being likely to cause invasive infection, had an insertion in the hylB gene (IS1548).


2018 ◽  
Vol 56 (12) ◽  
Author(s):  
Steven M. Lada ◽  
Karissa Huang ◽  
D. Jake VanBelzen ◽  
Luis J. Montaner ◽  
Una O'Doherty ◽  
...  

ABSTRACTWe utilized pulsed-field gel electrophoresis (PFGE) to purify high-molecular-weight DNA from HIV-infected cells. This purification, in combination with our previously described droplet digital PCR (ddPCR) assay, was used to develop a method to quantify proviral integrated HIV DNA free of lower-molecular-weight species of HIV DNA. Episomal 2-long-terminal-repeat (2-LTR) circles were completely cleared from HIV DNA samples. Technical replicates of the complete assay, starting with the same specimens, resulted in no statistical differences in quantification of integrated HIVgagsequences in cellular DNA from cells from HIV-infected subjects after prolonged treatment with antiretroviral therapy (ART). The PFGE ddPCR assay was compared to theAlu-gagquantitative PCR (qPCR) assay, the most widely used assay to measure proviral integrated HIV DNA. Spearman's rho nonparametric correlation determined PFGE ddPCR results to be positively correlated withAlu-gagqPCR results (r= 0.7052;P= 0.0273). In summary, PFGE ddPCR is a sensitive, reproducible, and robust method to measure proviral integrated HIV DNA and is theoretically more accurate than previously described assays, because it is a direct measure of integrated HIV DNA.


Genome ◽  
1989 ◽  
Vol 32 (6) ◽  
pp. 992-998 ◽  
Author(s):  
Nora L. V. Lapitan ◽  
Martin W. Ganal ◽  
Steven D. Tanksley

A karyotype of tomato mitotic chromosomes was constructed based on in situ hybridization to a 162-bp telomeric DNA repeat, TGRI. Variation in the spatial and quantitative distribution of this repeat creates distinct patterns for most of the chromosomes, which along with other morphological characteristics (i.e., length and arm length ratio), allow the identification of each of the 12 mitotic chromosomes of tomato. The structure and physical size of the TGRI clusters were further investigated by means of pulsed-field gel electrophoresis. Approximately 30 hybridizing fragments were observed in the range of 25 to 1000 kb when high molecular weight DNA was digested with BglII and probed with TGRI. The total molecular weight of these fragments is approximately 14 million bp, which is close to the estimated total length of TGRI in the genome (12.5 million bp) based on genomic reconstruction experiments. The results suggest that most of the TGRI clusters consist of single, uninterrupted blocks of satellite DNA. Assignment of somatic chromosomes, identified by TGRI hybridization to the previously established tomato linkage groups, was accomplished via in situ hybridization to mitotic spreads of primary trisomic lines. Using this information, we estimate the somatic length and DNA content of each of the tomato chromosomes and chromosome arms. Key words: Lycopersicon esculentum, somatic karyotype, in situ hybridization, satellite DNA, pulsed-field gel electrophoresis.


2004 ◽  
Vol 70 (7) ◽  
pp. 4205-4210 ◽  
Author(s):  
Charlene R. Jackson ◽  
Paula J. Fedorka-Cray ◽  
John B. Barrett ◽  
Scott R. Ladely

ABSTRACT The effect of tylosin on erythromycin-resistant enterococci was examined on three farms; farm A used tylosin for growth promotion, farm B used tylosin for treatment of disease, and farm C did not use tylosin for either growth promotion or disease treatment. A total of 1,187 enterococci were isolated from gestation, farrowing, suckling, nursery, and finishing swine from the farms. From a subset of those isolates (n = 662), 59% (124 out of 208), 28% (80 out of 281), and 2% (4 out of 170) were resistant to erythromycin (MIC ≥ 8 μg/ml) from farms A, B, and C, respectively. PCR analysis and Southern blotting revealed that 95% (65 out of 68) of isolates chosen from all three farms for further study were positive for ermB, but all were negative for ermA and ermC. By using Southern blotting, ermB was localized to the chromosome in 56 of the isolates while 9 isolates from farms A and B contained ermB on two similar-sized plasmid bands (12 to 16 kb). Pulsed-field gel electrophoresis revealed that the isolates were genetically diverse and represented a heterogeneous population of enterococci. This study suggests that although there was resistance to a greater number of enterococcal isolates on a farm where tylosin was used as a growth promotant, resistant enterococci also existed on a farm where no antimicrobial agents were used.


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