Podcasts about transcriptase

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.02.09.527879v1?rss=1 Authors: Jensen, G. S., Beaulieu, A. N., Curtis, C. D., Passarelli, J., Blaszkiewicz, M., Thomas, S., Morin, T., Willows, J. W., Greco, C. W., Brennan, C. J., Aniapam, C., Caron, L., Alves, M. J., Lynes, M. D., Carlone, D. L., Breault, D. T., Townsend, K. L. Abstract: Telomerase reverse transcriptase (TERT) is expressed by quiescent adult stem cells (ASC) in numerous adult murine and human tissues, but has never been explored in the adult brain. Here, we demonstrate that TERT+ cells in the adult mouse brain represent a novel population of multipotent ASCs that are localized to numerous classical neuro/gliogenic niches (including the ventricular-subventricular zone, hypothalamus, and olfactory bulb), as well as more recently described regions of adult brain plasticity such as the meninges and choroid plexus. Using a direct-reporter mouse line, we found that TERT+ cells expressed known neural stem cell markers such as Nestin and Sox2, but not markers of committed stem/progenitor cells, nor markers of mature neuronal or glial cells. TERT+ ASCs rarely expressed the proliferation marker Ki67, and in vitro TERT+ cells lost TERT expression when activated by growth factors, together indicating a quiescent phenotype similar to what has been observed in other tissues. When cultured, TERT+ cells behaved like neural stem cells by forming neurospheres, which could proliferate and become more metabolically active once stimulated by growth factors. TERT+ cells were observed in numerous brain niches, particularly near the ventricles and cerebrospinal fluid barriers, but notably, TERT+ cells were never observed in the hippocampus. Lineage tracing of TERT+ cells in adult transgenic mice (mTERTrtTA::oTET-Cre::RosamTmG) revealed large-scale expansion of TERT+ progeny and differentiation to diverse cell types in multiple brain regions. For example, lineage-traced cells expressed markers of mature neurons, oligodendrocytes, astrocytes, ependymal cells, and choroid epithelial cells, thus demonstrating the striking multipotency of this stem cell population in basal tissue turnover of the adult brain. Together, these data demonstrate that TERT+ cells represent a novel population of multipotent stem cells that contribute to basal plasticity and regeneration in the adult mouse brain. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Last episode we looked at the NRTIs now we have the NNRTIs. What's the difference besides the extra N you ask. Listen up and learn how they work they get used quite a bit.

Vincent travels to Cold Spring Harbor Laboratory to speak with David Baltimore, John Coffin, and Harold Various about the discovery in 1970 of retroviral reverse transcriptase and its impact on life sciences research. Hosts: Vincent Racaniello Guests: David Baltimore, John Coffin, and Harold Varmus Subscribe (free): Apple Podcasts, Google Podcasts, RSS, email Become a patron of TWiV! Links for this episode Fifty Years of Reverse Transcriptase (Cold Spring Harbor Laboratory) 50th Anniversary of RT discovery (Mol Biol Cell) RT in virions of Rous sarcoma virus – Temin (Nature) RNA-dependent DNA polymerase in tumor virus particles – Baltimore (Nature) Intro music is by Ronald Jenkees Send your virology questions and comments to twiv@microbe.tv

In this episode we discuss the first of the drug classes used to suppress the HIV virus. Nucleoside Reverse Transcriptase Inhibitors (NRTIs) were the first class of drugs approved way back in 1987. As usual we discuss how they work to suppress the virus, the associated kinetics and side effects to look out for.

A cquired immunodeficiency syndrome (AIDS) Awas first reported in 1981 in'homosexual men. AIDS is a retroviral disease caused by human immunodeficiency virus (HlV). The disease is characterized by immunosuppression, secondary neoplasma and neurological manifestations. AIDS is invariably fatal since there is no cure. In the USA, it is the fourth leading cause of death in men between the ages 15 to 55 years. No other disease has attracted as much aftention as AIDS by the governments, public and scientists. AIDS has stimulated an unprecedented amount of biomedical research which led to a major understanding ofthis deadfy disease within a short period of time. So rapid is the research on AIDS (particularly relating to molecular biofogy), any review is destined to be out of date by the time it is published! The isolation of human immunodeficiency virus (HIV) from lymphocytes of AIDS patients was independently achieved by Gallo (USA) and Montagnier (France) in 1984. Epidemiology AIDS was first described in USA and this country has the majority of reported cases. The prevalence of AIDS has been reported from almost every country. The number of people living with HfV worldwide is estimated to be around 40 million by the end of the year 2005. (lndia alone has about 5 million persons). At least 5 million deaths occurred in 2005, due to AIDS. AIDS is truely a global disease with an alarming increase in almost every country. Transmission of HIV : Transmission of AIDS essentially requires the exchange of body fluids (semen, vaginal secretions, blood, milk) containing the virus or virus-infected celfs. There are three major routes of HIV transmission- sexual contact, parenteral inoculation, and from infected mothers to their newborns. The distribution of risk factors for AIDS trans- mission are as follows. Sex between men (homosexuals) Sex between men and women - 60"/" -15%Intravenous drug abusers - 15"/" Transfusion of blood and blood products - 6% All others - 4o/o The predominant methods of HIV transmission (about 75o/") are through anal or vaginal intercourse. The risk for the transmission is much higher with anal than with vaginal intercourse. The practice of 'needle sharing' is mainly responsible for the transmission of HIV in drug abusers. Pediatric AIDS is mostly caused by vertical transmission (mother to infant). It should, however, be noted that HIV cannot be transmitted by casual personal contact in the household or work place. Further, the transmission of AIDS from an infected individual to health personnel attending on him is extremelv rAre. Virology of HIV AIDS is caused by a retrovirus, namely human immunodeficiency virus (HlY), belonging to lentivirus family. Retroviruses contain RNA as the genetic material. On entry into the host cell, they transcribe DNA which is a complementary copy of RNA. The DNA, in turn is used, as a template to produce new viral RNA copies. Two different forms of HlV, namely HIV-I and HIV-2 have been isolated from AIDS patients. HIV-1 is more common, being found in AIDS patients of USA, Canada, Europe and Central Africa while HIV-2 is mainly found in West Africa. Both the viruses are almost similar except they differ in certain immunological properties. HIV-1 is described in some detail. Structure of HIV : The viruse is spherical with a diameter of about 110 nm. lt contains a core, surrounded by a lipid envelop derived from the host pfasma membrane (Fig.3fl.l). The core of the HIV has two strands of genomic RNA and four core proteins, PZq, PtB, reverse tranScriptase (poolpsr) and endonuclease (p32). Note that the naming of the proteins is based on the molecular weight. For instance, a protein with a molecular weight of 24,0OO is designated as p2,4. The lipid membrane of the virus is studded with two glycoproteins Bprzo and gpot. The surface antigen 8p126 is very important for the viral infection CD4.

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Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.10.18.344481v1?rss=1 Authors: Wang, J. Y., Hoel, C. M., Al-Shayeb, B., Banfield, J. F., Brohawn, S. G., Doudna, J. A. Abstract: CRISPR-Cas systems provide adaptive immunity in bacteria and archaea by targeting foreign DNA for destruction using CRISPR RNA-guided enzymes. CRISPR immunity begins with integration of foreign sequences into the host CRISPR genomic locus, followed by transcription and maturation of CRISPR RNAs. In a few CRISPR systems, the Cas1 integrase and a Cas6 nuclease are fused to a reverse transcriptase that enables viral sequence acquisition from both DNA and RNA sources. To determine how these components work together, we determined a 3.7 [A] resolution cryo-EM structure of a Cas6-RT-Cas1 protein complexed with Cas2, a subunit of the CRISPR integrase. The structure and accompanying mutagenesis experiments provide evidence of bidirectional crosstalk between the Cas1 and RT active sites and unidirectional crosstalk from Cas6 to the Cas1 and RT active sites. Together, these findings suggest regulated structural rearrangements that may coordinate the complex's different enzymatic activities. Copy rights belong to original authors. Visit the link for more info

The TWiV hosts discuss the distribution of prions in the eyes of patients with sporadic Creutzfeldt-Jacob disease, and the origins and evolution of RNA viruses. Hosts: Vincent Racaniello, Alan Dove, Rich Condit, Kathy Spindler Subscribe (free): iTunes, Google Podcasts, RSS, email Become a patron of TWiV! Links for this episode Please take the TWiV listener survey ASV 2019 Satellite Symposia Crowdfunding for EV-D68 research Aaron Klug, 1926-2018 (Nature) Prions in sCJD eyes (mBio) Evolution of RNA viruses (mBio) Walter Gilbert's The RNA World (Nature) Image credit Letters read on TWiV 526 Timestamps by Jolene. Thanks! Weekly Science Picks Alan - Population mountains to visualize cities Rich- A Neanderthal Perspective on Human Origins with Svante Pääbo Kathy- NASA Space Mission posters Vincent - Package Thief vs Glitter Bomb Trap Listener Pick Neal- Was a Scientist Jailed? Intro music is by Ronald Jenkees. Send your virology questions and comments to twiv@microbe.tv

The TWiV hosts discuss the distribution of prions in the eyes of patients with sporadic Creutzfeldt-Jacob disease, and the origins and evolution of RNA viruses. Hosts: Vincent Racaniello, Alan Dove, Rich Condit, Kathy Spindler Subscribe (free): iTunes, Google Podcasts, RSS, email Become a patron of TWiV! Links for this episode Please take the TWiV listener survey ASV 2019 Satellite Symposia Crowdfunding for EV-D68 research Aaron Klug, 1926-2018 (Nature) Prions in sCJD eyes (mBio) Evolution of RNA viruses (mBio) Walter Gilbert's The RNA World (Nature) Image credit Letters read on TWiV 526 Timestamps by Jolene. Thanks! Weekly Science Picks Alan - Population mountains to visualize cities Rich- A Neanderthal Perspective on Human Origins with Svante Pääbo Kathy- NASA Space Mission posters Vincent - Package Thief vs Glitter Bomb Trap Listener Pick Neal- Was a Scientist Jailed? Intro music is by Ronald Jenkees. Send your virology questions and comments to twiv@microbe.tv

The TWiV posse considers viral insulin-like peptides encoded in fish genomes, and insect antiviral immunity by production of viral DNA from defective genomes of RNA viruses. Hosts: Vincent Racaniello, Dickson Despommier, Alan Dove, Kathy Spindler, and Brianne Barker Become a patron of TWiV! Links for this episode ASM Microbe 2018 Insulin-like peptides in Iridovirus genomes (PNAS) Dicer-2 dependent generation of cvDNA from defective genomes (Cell Host Micr) Carla Saleh on insect antiviral immunity (TWiV 301) RNAseIII ancient antiviral RNA platform (TWiV 450) cvDNA precursor to EVEs (TWiV 482) Image credit: Paul Young Letters read on TWiV 485 Weekly Science Picks Kathy - Vegas casinos lost money on physicists Brianne - Astronaut twin's DNA is not 7% different! Dickson - Parasitic Diseases lecture videos Alan - In Season blog by Donna Long Vincent - Buckyball viruses Listener Picks Paul - Wine labels (front, back) Intro music is by Ronald Jenkees. Send your virology questions and comments to twiv@microbe.tv

Hosts: Vincent Racaniello and Daniel Griffin Vincent and Daniel solve the case of the Family with Eosinophilia, and discuss HIV-1 infection and genome integration in the blood fluke Schistosoma mansoni. Become a patron of TWiP. Links for this episode: Family cluster of eosinophilia (Clin Inf Dis) Dientamoeba fragilis (Wikipedia) Parasites without borders HIV integrates into Schistosoma genome (PLoS Path) Image credit Letters read on TWiP 119 This episode is sponsored by CuriosityStream, a subscription streaming service that offers over 1,400 documentaries and non­fiction series from the world's best filmmakers. Get unlimited access starting at just $2.99 a month, and for our audience, the first two months are completely free if you sign up at curiositystream.com/microbe and use the promo code MICROBE. This episode is also sponsored by Drobo, a family of safe, expandable, yet simple to use storage arrays. Drobos are designed to protect your important data forever. Visit www.drobo.com to learn more. Case Study for TWiP 119 This one will be kinder and gentler case. Back in Thailand but could be in several places. 25 yo Thai woman from Bangkok, to hospital, chief complaint facial swelling. Eats typical Thai diet (see previous episodes!) Som tum, etc fish that is not cooked. Migratory - moves around face. Not tender, but mild itchiness. For about a week, no pain. Healthy, no past med/surg history, family all fine. HIV negative, no drugs, no travel. On examination, has swelling on right side, 3-4 cm raised, little redness, firm, does not feel like fluid filled. No fever, no GI problems, no bloods. WBC up, eosinophils up.  Send your case diagnosis, questions and comments to twip@microbe.tv

The purpose of the study reported here was to compare the antiviral efficacy against feline immunodeficiency virus (FIV) and cytotoxicity in feline peripheral blood mononuclear (PBM) cells of 9 nucleoside reverse transcriptase inhibitors (NRTIs), three of which had not been evaluated against FIV in feline cells before. PBM cells were isolated from the blood of three specific pathogen-free (SPF) cats. The cytotoxic effects of the test compounds were determined by colorimetric quantification of a formazan product resulting from bioreduction of a tetrazolium reagent by viable PBM cells. Each compound was tested in 12 concentrations ranging from 0.001 to 500 M. Uninfected cells from one SPF cat were used in these assays. PBM cells (from all three SPF cats) were infected with the molecular clone FIV pPPR and the antiviral efficacy of the test compounds was assessed using a FIV p24 antigen capture enzyme-linked immunosorbent assay. Each compound was tested in 5 concentrations ranging from 0.1 to 10 M. Cytotoxic effects in feline PBM cells were observed only at concentrations over 10 M for all 9 NRTIs. Comparison of the cytotoxic effect at the highest concentration investigated (500 M) revealed that didanosine and amdoxovir were significantly less toxic than abacavir. As no cytotoxicity was noted up to a concentration of 10 M, this was set as the highest concentration for the second part of this study investigating the anti-FIV efficacy of the test compounds. All drugs induced a dose-dependent reduction of FIV replication. When compared at the highest concentration investigated, there was no significant difference in the antiviral efficacy among the test compounds. The EC50 could not be determined as none of the test compounds achieved 50% viral inhibition. The evaluated NRTIs had low cytotoxicity against feline PBM cells and appear to be safe options for further in vivo evaluation for the treatment of FIV-infected cats. There was no evidence suggesting that the newly evaluated compounds would be superior to the existing NRTIs for reducing the FIV burden of infected cats.

Host: Vincent Racaniello Guest: John Coffin Vincent speaks with John Coffin about his career studying retroviruses, including working with Howard Temin, endogenous retroviruses, XMRV, chronic fatigue syndrome and prostate cancer, HIV/AIDS, and his interest in growing cranberries. Links for this episode John Coffin (Wikipedia) Specific HIV integration sites (Science) Novel retrovirus in modern birds (J Virol) Recombinant origin of XMRV (Science) Cranberry harvest (jpg) Send your virology questions and comments (email or mp3 file) to twiv@twiv.tv

Host: Vincent Racaniello Guests: Carla Saleh and Curtis Suttle At the International Congress of Virology in Montreal, Vincent speaks with Carla and Curtis about their work on RNA interference and antiviral defense in fruit flies, and viruses in the sea, the greatest biodiversity on Earth. Links for this episode Greatest biodiversity on Earth (Genome) Cafeteria roenbergensis virus (PNAS) Marine viruses (Nat Rev Micro) RNAi and reverse transcription is antiviral in flies (Nat Imm) Friendly persistent infections (Curr Op Micro) RNAi and antiviral defense in Drosophila (Dev Comp Imm) Video of this episode - view at YouTube Send your virology questions and comments (email or mp3 file) to twiv@twiv.tv

Host: Vincent Racaniello Guests: Melissa Churchill, Alex Khromykh, Gilda Tachedjian, and Paul Young Vincent visits Melbourne, Australia and speaks with Melissa, Alex, Gilda, and Paul about their work on HIV infection of the central nervous system, West Nile virus, microbicides for HIV, and the Koala retrovirus. Links for this episode Where does HIV hide? (Curr Op HIV AIDS) Subgenomic flavivirus RNA (Viruses) Vaginal lactic acid and HIV (J Antimicro Chem) Koala retroviruses (Retrovirology) Coming soon - Video of this episode at YouTube Send your virology questions and comments (email or mp3 file) to twiv@twiv.tv  

Hosts: Vincent Racaniello, Dickson Despommier, Alan Dove, Rich Condit, and Kathy Spindler The Twivsters discuss how reverse transcriptase encoded in the human genome might produce DNA copies of RNA viruses in infected cells. Links for this episode Should variola virus be destroyed? (poll at virology blog) DNA complementary to non-retroviral RNA viruses (Sci Rep) Integration of arenavirus DNA into cell genome (virology blog) Infectious respiratory syncytial DNA (PNAS) Tysabri and PML JC and PML (J Imm Res) Igor Koralnik laboratory Jean-Luc Doumont (Kathy's pick, TWiV 268) Bullet points kill (TED) Letters read on TWiV 288 Weekly Science Picks Rich - LuvalampsAlan - ExperimentVincent - American Society for Virology on FacebookKathy - LEGO female scientistsDickson - The Oldest Living Things in the World by Rachel Sussman Listener Pick of the Week Basel - A Treatise on the small-pox and measles by Abu-Bakr Al-Razi Send your virology questions and comments (email or mp3 file) to twiv@twiv.tv

Vincent, Elio, and Michael discuss how an error-prone reverse transcriptase produces enormous diversity in a Legionella protein, and using microbes to convert waste into bioelectricity and chemicals.

Sun, 1 Jan 2012 12:00:00 +0100 http://www.plosntds.org/article/info%3Adoi%2F10.1371%2Fjournal.pntd.0001756 https://epub.ub.uni-muenchen.de/15746/1/oa_15755.pdf Bretzel, Gisela; Adjei, Ohene; Loescher, Thomas; Battke, Florian; Herbinger, Karl-Heinz; Huber, Kristina Lydia; Jansson, Moritz; Sarfo, Fred Stephen; Awua-Boateng, Nana-Yaa; Amoako, Yaw Ampem; Phillips, Richard Odame; Symank, Dominik; Beissner, Marcus

Vincent, Dickson, Rich, and Alan review the 100 year old finding by Peyton Rous of a transmissible sarcoma of chickens, a discovery that ushered in the era of tumor virology.

Vincent, Alan, and Rich celebrate the 100th episode of TWiV by talking about viruses with Nobel Laureate David Baltimore.

Development of the musculosceletal system requires coordinated formation of distinct types of tissues, including bone, cartilage, muscle and tendon. Compared to muscle, cartilage and bone, molecular, cellular and developmental biology of tendon have not been well understood due to the lack of tendon cell lines. In addition tissue engineering of tendon is hampered by the rather difficult retrieval of tenocytes and their senescence-associated growth arrest during culture. Therefore the purpose of this study was to establish and characterize human tendon cell lines. Two tendon cell lines (HTD2 hTERT and HTD5 hTERT) were established using lentiviral gene transfer to ectopically express hTERT. The cell lines stably expressed hTERT on RNA and protein level. Untransduced cultured tenocytes show only a background level of telomerase activity, but it was significantly increased by hTERT transduction. Ectopic expression of hTERT led to an extended lifespan and prevented senescence while the cells kept their typical spindle-shaped morphology of young primary human tenocytes. Moreover, in comparison to untransduced tenocytes the cells possessed significantly lesser β-galactosidase activity indicating that they had not entered a senescent state. Throughout the entire culturing period the hTERT transduced tenocytes expressed tendon-related genes such as those encoding collagen I, collagen III, Tenascin C, EphA4, Eya1, scleraxis, Six and COMP. Using soft agar assay, no malignant transformation was shown by the hTERT expressing tenocytes. In conclusion, extending the lifespan of human tenocytes by ectopic expression of hTERT using lentiviral gene transfer may be an attractive and safe way to generate cells allowing extensive molecular characterization and development of novel tissue engineering applications.

On episode #66 of the podcast This Week in Virology, Vincent and Dickson continue virology 101 with a discussion of information flow from RNA to DNA, a process known as reverse transcription, which occurs in cells infected with retroviruses, hepatitis B virus, cauliflower mosaic virus, foamy viruses, and even in uninfected cells. Host links Vincent Racaniello and Dickson Despommier Links for this episode: Discovery of RNA tumor viruses Reverse transcriptase found by Temin and Baltimore (pdfs) Figures for this episode

Audio Journal of Global Health Issues Three-Class Antiretroviral Therapy for HIV Not Appropriate: Results from the FIRST Study REFERENCE: Lancet 2006; 368: 2125-35 RODGER MacARTHUR, Wayne State University, Detroit A three-class HIV antiretroviral therapy is not necessary, according to data published in the Lancet. The FIRST study had three arms which included non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs), or both, all in the presence of nucleoside reverse transcriptase inhibitors. Derek Thorne heard more from Rodger MacArthur of Wayne State University in Detroit.