scholarly journals Characterization of Episomal Replication of Bovine Papillomavirus Type 1 DNA in Long-Term Virion-Infected Saccharomyces Cerevisiae Culture

2021 ◽  
Author(s):  
Quanmei Tu ◽  
Weixu Feng ◽  
Zhuo Chen ◽  
Qijia Li ◽  
Yu Zhao ◽  
...  
Keyword(s):  
Time Course ◽  
Blot Hybridization ◽  
Yeast Cells ◽  
Bovine Papillomavirus ◽  
Two Dimensional Gel Electrophoresis ◽  
Yeast Cultures ◽  
Active Replication ◽  
Replication Intermediates

AbstractWe have previously reported that bovine papillomavirus type 1 (BPV-1) DNA can replicate its genome and produce infectious virus-like particles in short term virion-infected S. cerevisiae (budding yeast) cultures (Zhao and Frazer 2002, Journal of Virology, 76:3359–64 and 76:12265–73). Here, we report the episomal replications of BPV-1 DNA in long term virion-infected S. cerevisiae culture up to 108 days. Episomal replications of the BPV-1 DNA could be divided into three patterns at three stages, early active replication (day 3–16), middle weak replication (day 23–34/45) and late stable replication (day 45–82). Two-dimensional gel electrophoresis analysis and Southern blot hybridization have revealed further that multiple replication intermediates of BPV-1 DNA including linear form, stranded DNA, monomers and higher oligomers were detected in the virion-infected yeast cells over the time course. Higher oligomers shown as covalently closed circular DNAs (cccDNAs) are the most important replication intermediates that serve as the main nuclear transcription template for producing all viral RNAs in the viral life cycle. In this study, the cccDNAs were generated at the early active replication stage with the highest frequencies and then at late stable replication, but they appeared to be suppressed at the middle weak replication. Our data provided a novel insight that BPV-1 genomic DNA could replicate episomally for the long period and produce the key replication intermediates cccDNAs in S. cerevisiae system.

scholarly journals Chronological aging leads to apoptosis in yeast

2004 ◽  
Vol 164 (4) ◽  
pp. 501-507 ◽  
Author(s):  
Eva Herker ◽  
Helmut Jungwirth ◽  
Katharina A. Lehmann ◽  
Corinna Maldener ◽  
Kai-Uwe Fröhlich ◽  
...  
Keyword(s):  
Apoptotic Cell ◽  
Selective Advantage ◽  
Yeast Cells ◽  
Unicellular Organism ◽  
Chronological Aging ◽  
Beneficial Effects ◽  
Yeast Cultures ◽  
A Cell ◽  
Cell Suicide

During the past years, yeast has been successfully established as a model to study mechanisms of apoptotic regulation. However, the beneficial effects of such a cell suicide program for a unicellular organism remained obscure. Here, we demonstrate that chronologically aged yeast cultures die exhibiting typical markers of apoptosis, accumulate oxygen radicals, and show caspase activation. Age-induced cell death is strongly delayed by overexpressing YAP1, a key transcriptional regulator in oxygen stress response. Disruption of apoptosis through deletion of yeast caspase YCA1 initially results in better survival of aged cultures. However, surviving cells lose the ability of regrowth, indicating that predamaged cells accumulate in the absence of apoptotic cell removal. Moreover, wild-type cells outlast yca1 disruptants in direct competition assays during long-term aging. We suggest that apoptosis in yeast confers a selective advantage for this unicellular organism, and demonstrate that old yeast cells release substances into the medium that stimulate survival of the clone.

Evidence that replication initiates at only some of the potential origins in each oligomeric form of bovine papillomavirus type 1 DNA

1990 ◽  
Vol 10 (6) ◽  
pp. 3078-3086
Author(s):  
J B Schvartzman ◽  
S Adolph ◽  
L Martín-Parras ◽  
C L Schildkraut
Keyword(s):  
Dna Replication ◽  
The Other ◽  
Bovine Papillomavirus ◽  
Two Dimensional Gel Electrophoresis ◽  
Dna Oligomers ◽  
Latently Infected ◽  
Oligomeric Form ◽  
Multiple Copies ◽  
Initiation Of Dna Replication

In a subclone of ID13 mouse fibroblasts latently infected with bovine papillomavirus type 1 (BPV-1) DNA, the viral genome occurred as a mixture of extrachromosomal circular monomers and oligomers. Multiple copies were also associated with the host cell genome, predominantly at a single site in a head-to-tail tandem array. We examined the replicative intermediates of extrachromosomal forms of BPV-1 DNA by using two-dimensional gel electrophoresis. The results obtained indicate that initiation of DNA replication occurred near the center of the EcoRI-BamHI 5.6-kilobase fragment. In some molecules, however, this fragment was replicated from one end to the other by means of a single fork initiated elsewhere. Termination also occurred within this fragment. The EcoRI-BamHI 2.3-kilobase fragment replicated as a DNA molecule containing a termination site for DNA replication and also by means of a single fork traversing the fragment from one end to the other. Thus, replication forks proceeded through these fragments in different manners, apparently depending on whether they were part of a monomer, a dimer, a trimer, or higher oligomers. These observations lead to the conclusion that initiation of DNA replication in BPV-1 DNA takes place at or close to plasmid maintenance sequence 1. From this point, replication proceeds bidirectionally and termination occurs approximately 180 degrees opposite the origin. The results obtained are consistent with one or more replication origins being quiescent in BPV-1 DNA oligomers.

scholarly journals Evidence that replication initiates at only some of the potential origins in each oligomeric form of bovine papillomavirus type 1 DNA.

1990 ◽  
Vol 10 (6) ◽  
pp. 3078-3086 ◽  
Author(s):  
J B Schvartzman ◽  
S Adolph ◽  
L Martín-Parras ◽  
C L Schildkraut
Keyword(s):  
Dna Replication ◽  
The Other ◽  
Bovine Papillomavirus ◽  
Two Dimensional Gel Electrophoresis ◽  
Dna Oligomers ◽  
Latently Infected ◽  
Oligomeric Form ◽  
Multiple Copies ◽  
Initiation Of Dna Replication

In a subclone of ID13 mouse fibroblasts latently infected with bovine papillomavirus type 1 (BPV-1) DNA, the viral genome occurred as a mixture of extrachromosomal circular monomers and oligomers. Multiple copies were also associated with the host cell genome, predominantly at a single site in a head-to-tail tandem array. We examined the replicative intermediates of extrachromosomal forms of BPV-1 DNA by using two-dimensional gel electrophoresis. The results obtained indicate that initiation of DNA replication occurred near the center of the EcoRI-BamHI 5.6-kilobase fragment. In some molecules, however, this fragment was replicated from one end to the other by means of a single fork initiated elsewhere. Termination also occurred within this fragment. The EcoRI-BamHI 2.3-kilobase fragment replicated as a DNA molecule containing a termination site for DNA replication and also by means of a single fork traversing the fragment from one end to the other. Thus, replication forks proceeded through these fragments in different manners, apparently depending on whether they were part of a monomer, a dimer, a trimer, or higher oligomers. These observations lead to the conclusion that initiation of DNA replication in BPV-1 DNA takes place at or close to plasmid maintenance sequence 1. From this point, replication proceeds bidirectionally and termination occurs approximately 180 degrees opposite the origin. The results obtained are consistent with one or more replication origins being quiescent in BPV-1 DNA oligomers.

A model for long term infection of bovine papillomavirus type 1 in Saccharomyces cerevisiae

2021 ◽  
Author(s):  
Jun Chen ◽  
Qijia Li ◽  
Weixu Feng ◽  
Zhuo Chen ◽  
Qi Wang ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Bovine Papillomavirus

scholarly journals Induction of the Bovine Papillomavirus Origin “Onion Skin”-Type DNA Replication at High E1 Protein Concentrations In Vivo

2002 ◽  
Vol 76 (11) ◽  
pp. 5835-5845 ◽  
Author(s):  
Andres Männik ◽  
Kertu Rünkorg ◽  
Nele Jaanson ◽  
Mart Ustav ◽  
Ene Ustav
Keyword(s):  
Dna Replication ◽  
Skin Type ◽  
Bovine Papillomavirus ◽  
Two Dimensional Gel Electrophoresis ◽  
Reading Frame ◽  
E1 Protein ◽  
Onion Skin ◽  
Origin Region ◽  
Replication Intermediates

ABSTRACT We have studied the replication of plasmids composed of bovine papillomavirus type 1 (BPV1) origin of replication and expression cartridges for viral proteins E1 and E2 in hamster and mouse cells. We found that the replication mode changed dramatically at different expression levels of the E1 protein. At high levels of the E1 protein, overreplication of the origin region of the plasmid was observed. Analysis of the replication products by one-dimensional and two-dimensional gel electrophoresis suggested that initially “onion skin”-type replication intermediates were generated, presumably resulting from initiation of the new replication forks before the leading fork completed the synthesis of the DNA on the episomal plasmid. These replication intermediates served as templates for generation of a heterogeneous set of origin region-containing linear fragments by displacement synthesis at the partially replicated plasmid. Additionally, the linear fragments may have been generated by DNA break-up of the onion skin-type intermediates. Analysis of replication products indicated that generated linear fragments recombined and formed concatemers or circular molecules, which presumably were able to replicate in an E1- and E2-dependent fashion. At moderate and low levels of E1, generated by transcription of the E1 open reading frame using weaker promoters, DNA replication was initiated at much lower levels, which allowed elongation of the replication fork starting from the origin to be more balanced and resulted in the generation of full-sized replication products.

Photoacoustic Spectroscopy and Hyperglycemia in Experimental Type 1 Diabetes

2021 ◽  
pp. 000370282110472
Author(s):  
Lilia I. Olvera Cano ◽  
Guadalupe C. Villanueva Lopez ◽  
Evelyn Romero Mateos ◽  
Alfredo Cruz Orea
Keyword(s):  
Type 1 Diabetes ◽  
Optical Absorption ◽  
Photoacoustic Spectroscopy ◽  
Time Course ◽  
Diabetes Complications ◽  
Area Under The Curve ◽  
World Health ◽  
Male Wistar Rats

According to the World Health Organization, diabetes was the seventh leading cause of death in 2016. Long-term diabetes complications are associated with hyperglycemia. It is difficult to predict the beginning and evolution of those complications. The goal of the study was to evaluate the relationship between glycemia and blood spectroscopic variables in an experimental model of type 1 diabetes (streptozotocin model). Blood samples were taken weekly (10 weeks) from the tail of male Wistar rats with or without diabetes. Blood optical absorption spectra were obtained by means of photoacoustic spectroscopy. It was possible to estimate the time-course of blood characteristic peak ratios. The area under the curve of those peaks correlated with hyperglycemia. The evolution of the optical absorption at 450 nm, related to cytochrome p450, was obtained by using the phase-resolved method. The area under the curve of p450 correlated also with hyperglycemia. It is concluded that photoacoustic spectroscopy is a reliable technology to detect the effects of hyperglycemia on blood with possible applications in the study of long-term diabetes complications.

scholarly journals Replication of Bovine Papillomavirus Type 1 (BPV-1) DNA in Saccharomyces cerevisiae following Infection with BPV-1 Virions

2002 ◽  
Vol 76 (7) ◽  
pp. 3359-3364 ◽  
Author(s):  
Kong-Nan Zhao ◽  
Ian H. Frazer
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Blot Hybridization ◽  
Southern Blot Hybridization ◽  
Restriction Map ◽  
Bovine Papillomavirus ◽  
Restriction Digestion ◽  
Two Dimensional ◽  
Cell Wall Regeneration ◽  
Replicative Intermediates

ABSTRACT Saccharomyces cerevisiae protoplasts exposed to bovine papillomavirus type 1 (BPV-1) virions demonstrated uptake of virions on electron microscopy. S. cerevisiae cells looked larger after exposure to BPV-1 virions, and cell wall regeneration was delayed. Southern blot hybridization of Hirt DNA from cells exposed to BPV-1 virions demonstrated BPV-1 DNA, which could be detected over 80 days of culture and at least 13 rounds of division. Two-dimensional gel analysis of Hirt DNA showed replicative intermediates, confirming that the BPV-1 genome was replicating within S. cerevisiae. Nicked circle, linear, and supercoiled BPV-1 DNA species were observed in Hirt DNA preparations from S. cerevisiae cells infected for over 50 days, and restriction digestion showed fragments hybridizing to BPV-1 in accord with the predicted restriction map for circular BPV-1 episomes. These data suggest that BPV-1 can infect S. cerevisiae and that BPV-1 episomes can replicate in the infected S. cerevisiae cells.

Long-Term Outlook Improving for Type 1 Patients

2008 ◽  
Vol 38 (21) ◽  
pp. 14
Author(s):  
MIRIAM E. TUCKER
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