Podcasts about amoebae

Matters Microbial #79: How Amoebae Beat the Heat February 20, 2025 Today, Dr. Angela Oliverio, Assistant Professor in the Biology Department at Syracuse University, joins the #QualityQuorum to discuss what her research group has been learning about extremophilic single-celled eukaryotes! Host: Mark O. Martin Guest: Angela Oliverio Subscribe: Apple Podcasts, Spotify Become a patron of Matters Microbial! Links for this episode An overview of protists.   A wondrous video of the types of protists to be found seemingly everywhere. A video about amoebae and how YOU can find them.   A video about the testate amoebae mentioned in this podcast. An essay about the testate amoebae. A very old article on temperature limits to eukaryotic life. A more modern article on this topic. An article from Dr. Oliverio's group on the temperature limits to eukaryotic life. The Mullin laboratory at UCSF does remarkable visualization. Genomics and the Lawrence Livermore Laboratory. How mycoplasma move, with remarkable videos. A member of Dr. Oliverio's lab creates beautiful glass art at this Etsy shop. A wonderful local news report on Dr. Oliverio and coworker's research. A nice overview of Dr. Oliverio's research interest in extremophilic protists. An article from Dr. Oliverio's group explaining why we should all care about extremophilic eukaryotes. Dr. Oliverio's research website (and SO worth your time) Dr. Oliverio's faculty website. Intro music is by Reber Clark Send your questions and comments to mattersmicrobial@gmail.com

Hidden in the microverse all around you, there is a merciless war being fought by the true rulers of this planet, microorganisms. Amoebae, protists, bacteria, archaea and fungi compete for resources and space. And then there are the strange horrors that are viruses, hunting everyone else. Not even being alive, they are the tiniest, most abundant and deadliest beings on earth, killing trillions every day. Not interested in resources, only in living things to take over. Or so we thought. It turns out that there are giant viruses that blur the line between life and death – and other viruses hunting them. Sources & further reading: https://sites.google.com/view/sources... Give the show a 5 STAR Review ⭐️ We Highly Appreciate It! Follow the show to join us in this audio experience of Kurzgesagt - In a Nutshell. A fan-made show out of admiration for the works of Kurzgesagt - In a Nutshell. Learn more about your ad choices. Visit megaphone.fm/adchoices

This episode: Slime mold amoebas Fonticula alba have interesting and unique foraging and reproductive behaviors! Download Episode (7.3 MB, 10.6 minutes) Show notes: Microbe of the episode: Cajanus cajan Panzee virus News item   Takeaways How did life develop from single-celled organisms acting independently into the complex, multicellular organisms we see and are today? Although it is difficult to look back through time to study how ancient organisms may have developed along this path, it is possible to investigate modern organisms that occupy a zone in between single-celled and multicellular, to see if we can get some hints to our own development, and also learn about some interesting microbes along the way! This study into the social amoeba, or slime mold, Fonticula alba, finds that the individual amoebal cells in a population join together into collectives and break apart into individuals at different stages of their complex life cycle, depending on the status of the bacteria around them that they forage as prey. The investigators tease out the various pathways taken by these amoebas.   Journal Paper: Toret C, Picco A, Boiero-Sanders M, Michelot A, Kaksonen M. 2022. The cellular slime mold Fonticula alba forms a dynamic, multicellular collective while feeding on bacteria. Curr Biol 32:1961-1973.e4. Email questions or comments to bacteriofiles at gmail dot com. Thanks for listening! Subscribe: Apple Podcasts, Google Podcasts, Android, or RSS. Support the show at Patreon, or check out the show at Twitter or Facebook.

Team 1: Martin, Darren, Lee and Jamie from York. Team 2: Christopher, James, Alex and Tim from Bristol In which Morghanna breaks some glass. Support us on Patreon Visit our Website Follow us on Twitter Check out our Redbubble Store Theme music: The Castle of Confusion by Chris Jerden-Cooke "Trip to the Heifer", a parody of Cornershop and Norman Cook's "Brimful of Asha - the Norman Cook Mix", was written by Drassil on the knightmare.com forums and has been used with his permission. The backing track is used for the purpose of parody. --- Send in a voice message: https://anchor.fm/knightmarepod/message

Other horrible things we address include a Medicare claim denial booklet addressed to the wrong party, weird looking people on the cover of the newest "Medicare and You" government guide book and correspondence from a reader in Massachusetts seeking professional advice.  Inspired by "MEDICARE FOR THE LAZY MAN 2020; Simplest & Easiest Guide Ever!" on Amazon.com and BarnesandNoble.com. Return to leave a short customer review & help future readers.Official website: https://www.MedicareForTheLazyMan.comSend questions & love notes: DBJ@MLMMailbag.com

This episode: A newly discovered species of bacteria consumes other bacteria as prey by engulfing them! Download Episode (8.7 MB, 12.6 minutes) Show notes: Microbe of the episode: SARS-CoV-2! This is the coronavirus responsible for COVID-19, the current pandemic. For more up-to-date information, please refer to the American Society for Microbiology, This Week in Virology, and other reputable sources. Stay healthy! Takeaways There are bacteria living almost every different lifestyle you can think of, including predatory, preying on other bacteria. Since bacterial cells are usually quite rigid, bacterial predators usually consume others either by burrowing inside them or digesting them from outside, rather than engulfing prey like eukaryotes often do. The study here discovers a new kind of bacteria, in the group called Planctomycetes, known for having unusually flexible cells and internal compartments like eukaryotes. This new species does engulf its prey, including bacteria and even tiny algae, and digests them inside itself. It possesses multiple adaptations that suit it for this lifestyle. Journal Paper: Shiratori T, Suzuki S, Kakizawa Y, Ishida K. 2019. Phagocytosis-like cell engulfment by a planctomycete bacterium. Nat Commun 10:1–11. Other interesting stories: Engineering a common industrial yeast strain to fix carbon dioxide (paper) Lake microbes convert microplastics into essential fatty acids   Email questions or comments to bacteriofiles at gmail dot com. Thanks for listening! Subscribe: Apple Podcasts, Google Podcasts, Android, or RSS. Support the show at Patreon, or check out the show at Twitter or Facebook.

This episode: Bacterial symbionts of amoebas help them survive bacterial infection, and prevent pathogens from spreading to others as much! Download Episode (7.5 MB, 8.1 minutes) Show notes: Microbe of the episode: Eubacterium dolichum News item Takeaways Amoebas are free-living, single-celled organisms, but they have some things in common with some cells of our immune system (macrophages). For example, certain bacterial pathogens can infect both in similar ways. So it can be useful to study the interactions of amoebas and bacteria to learn about our own immune defenses. In this study, the amoeba Acanthamoeba castellanii has another bacterial symbiont that helps it resist killing by the bacterial pathogen Legionella pneumophila. Once the amoebas recovered from the infection, they were more resistant to future challenges. Even better, the symbiont prevented the pathogen from transforming into a more spreadable form like it does when infecting amoebas alone. Journal Paper: König L, Wentrup C, Schulz F, Wascher F, Escola S, Swanson MS, Buchrieser C, Horn M. 2019. Symbiont-Mediated Defense against Legionella pneumophila in Amoebae. mBio 10:e00333-19. Other interesting stories: RNA-cutting CRISPR/Cas system induces bacterial dormancy to prevent phage replication Gut bacteria degrade/modify many different kinds of drugs (paper)   Email questions or comments to bacteriofiles at gmail dot com. Thanks for listening! Subscribe: Apple Podcasts, RSS, Google Play. Support the show at Patreon, or check out the show at Twitter or Facebook

This episode: A marine protist can orient itself along magnetic fields thanks to bacterial symbionts on its surface that make magnetic nanoparticles! Download Episode (7.2 MB, 7.9 minutes) Show notes: Microbe of the episode: Chlorocebus pygerythrus polyomavirus 3 Takeaways Various kinds of bacteria can orient their movement along a magnetic field. These are called magnetotactic, and they use this ability to swim toward or away from the surface of their aquatic habitat, to adjust their oxygen exposure according to their preference. No eukaryotic microbes have yet been discovered that can sense and react to magnetic fields like these prokaryotes. In this study, however, a protist was discovered that can do it via its partnership with ectosymbionts, or bacteria attached to its surface, that sense magnetism and orient their host's movement. In return, factors of the host's metabolism may feed its symbionts. Journal Paper: Monteil CL, Vallenet D, Menguy N, Benzerara K, Barbe V, Fouteau S, Cruaud C, Floriani M, Viollier E, Adryanczyk G, Leonhardt N, Faivre D, Pignol D, López-García P, Weld RJ, Lefevre CT. 2019. Ectosymbiotic bacteria at the origin of magnetoreception in a marine protist. Nat Microbiol 4:1088–1095. Other interesting stories: Fungus infects mosquitoes and quickly kills them with engineered toxin Nose microbe helps mediate immune response to flu virus, in mouse study (paper)   Email questions or comments to bacteriofiles at gmail dot com. Thanks for listening! Subscribe: Apple Podcasts, RSS, Google Play. Support the show at Patreon, or check out the show at Twitter or Facebook

This episode: Fungus-hunting amoebas have different strategies for detecting and preying on single-celled and filamentous fungi! Also, a personal note: I'm going to be taking a few weeks off the podcast to be able to take full advantage of spring, but I'll be back as soon as the weather gets too hot. Download Episode (7.5 MB, 8.2 minutes) Show notes: Microbe of the episode: Chondromyces catenulatus Takeaways Amoebas in the microbial world are like powerful predators, going around gobbling up whatever they find that's small enough, by a process called phagocytosis, in which they surround their prey with their cell membrane and engulf it. It's similar to macrophages or white blood cells as part of our immune system in our bodies. The prey of amoebas includes bacteria, large viruses, and single-celled fungi called yeasts. In this study, scientists showed that some yeasts make great food sources for a certain kind of amoeba called Protostelium aurantium, while others either lack nutritional value or hide from the predators by covering up certain recognition molecules on their cell wall. They found that the amoebas could also consume the spores of filamentous fungi, and could even attack the filaments, or hyphae. In this latter case, instead of engulfing the large filaments, they pierced the cells and extracted their contents, an approach named ruphocytosis, from the Greek for suck or slurp. Journal Paper: Radosa S, Ferling I, Sprague JL, Westermann M, Hillmann F. The different morphologies of yeast and filamentous fungi trigger distinct killing and feeding mechanisms in a fungivorous amoeba. Environ Microbiol. Other interesting stories: Finding potential antimicrobials from ant bacteria   Email questions or comments to bacteriofiles at gmail dot com. Thanks for listening! Subscribe: Apple Podcasts, RSS, Google Play. Support the show at Patreon, or check out the show at Twitter or Facebook

The TWiV team discusses Medusavirus, isolated from a hot spring in Japan, and induction of neurodegeneration by recurrent herpes simplex virus 1 infection of mice. Hosts: Vincent Racaniello, Dickson Despommier, Alan Dove, Rich Condit, Kathy Spindler, and Brianne Barker Subscribe (free): iTunes, Google Podcasts, RSS, email Become a patron of TWiV! Links for this episode Medusavirus (J Virol) Recurrent herpes simplex virus-1 and Alzheimer's (PLoS Path) Image credit Letters read on TWiV 543 Timestamps by Jolene. Thanks! Weekly Science Picks Brianne - How to Take a Picture of a Black Hole Alan- Jupiter Marbleimage Rich - NASA Commercial Crew Program; How SpaceX and Boeing will get Astronauts to the ISS; Everyday Astronaut Dickson- Sky-High Stunners Kathy- Arts at Michigan photo winnersand UM Microscopy Core image contest winners Vincent - NYC declares emergency over measles outbreak, mandates vaccinations and EMDataResource Listener Pick Martin- Sydney Brenner passes Intro music is by Ronald Jenkees. Send your virology questions and comments to twiv@microbe.tv

The TWiV team discusses Medusavirus, isolated from a hot spring in Japan, and induction of neurodegeneration by recurrent herpes simplex virus 1 infection of mice. Hosts: Vincent Racaniello, Dickson Despommier, Alan Dove, Rich Condit, Kathy Spindler, and Brianne Barker Subscribe (free): iTunes, Google Podcasts, RSS, email Become a patron of TWiV! Links for this episode Medusavirus (J Virol) Recurrent herpes simplex virus-1 and Alzheimer's (PLoS Path) Image credit Letters read on TWiV 543 Timestamps by Jolene. Thanks! Weekly Science Picks Brianne - How to Take a Picture of a Black Hole Alan- Jupiter Marbleimage Rich - NASA Commercial Crew Program; How SpaceX and Boeing will get Astronauts to the ISS; Everyday Astronaut Dickson- Sky-High Stunners Kathy- Arts at Michigan photo winnersand UM Microscopy Core image contest winners Vincent - NYC declares emergency over measles outbreak, mandates vaccinations and EMDataResource Listener Pick Martin- Sydney Brenner passes Intro music is by Ronald Jenkees. Send your virology questions and comments to twiv@microbe.tv

This episode: Newly discovered giant virus from a hot spring turns its amoeba hosts to stone! Download Episode (6.7 MB, 7.3 minutes) Show notes: Microbe of the episode: Listeria virus P70 News item Takeaways Viruses come in endless different shapes, sizes, and genetic configurations. Even within the group called giant viruses there is a large amount of variety. Many of their genes are unknown, without homology to any other sequences we have acquired in other areas of life. There is great potential to learn interesting things from these viruses. In this study, a new giant virus is discovered. Like many others, this infects amoebas, and causes them to transform from dynamic, shape-shifting cells into hard little cyst-like circles. This ability gave it the name Medusavirus. It's the first giant virus found in a relatively hot environment (a hot spring), and among other interesting features, it shows signs of multiple instances of gene transfer to and from its amoeba host. Journal Paper: Yoshikawa G, Blanc-Mathieu R, Song C, Kayama Y, Mochizuki T, Murata K, Ogata H, Takemura M. 2019. Medusavirus, a novel large DNA virus discovered from hot spring water. J Virol JVI.02130-18. Other interesting stories: Bacteria on frog skin have antifungal potential Phages could enhance effectiveness of antibiotics against pathogen biofilms (paper) Cement-generating bacteria could make coal ash easier to store safely (paper)   Email questions or comments to bacteriofiles at gmail dot com. Thanks for listening! Subscribe: Apple Podcasts, RSS, Google Play. Support the show at Patreon, or check out the show at Twitter or Facebook

**Warning: not so great sound quality** Do you sinus rinse, have cats, and want kids? This one’s for you.   In this episode, we discuss Toxoplasma gondii infections, one of the most commonly found parasites and Naegleria fowleri, a brain-eating amoeba. 

This episode: New type of secretion system discovered that bacteria use to stab amoeba predators to escape their digestion! Download Episode (7.8 MB, 8.5 minutes) Show notes: Microbe of the episode: Avastrovirus 1 News item Journal Paper: Böck D, Medeiros JM, Tsao H-F, Penz T, Weiss GL, Aistleitner K, Horn M, Pilhofer M. 2017. In situ architecture, function, and evolution of a contractile injection system. Science 357:713–717. Other interesting stories: Gut microbe metabolites keep yeasts from taking over (paper) Ancient fungi extracted minerals that helped ancient plants create oxygen How microbes survive on and affect tombstones (paper) Stomach bacterium produces interesting anti-inflammatory compound (paper) Finding archaea in the human lung, gut, skin, and nose (paper)   Email questions or comments to bacteriofiles at gmail dot com. Thanks for listening! Subscribe: iTunes, RSS, Google Play. Support the show at Patreon, or check out the show at Twitter or Facebook

This episode: Individual slime molds show the ability to learn about their environment! Download Episode (8.8 MB, 9.6 minutes) Show notes: News item Journal Paper: Boisseau RP, Vogel D, Dussutour A. 2016. Habituation in non-neural organisms: evidence from slime moulds. Proc R Soc B 283:20160446. Other interesting stories: Lactobacilli could control fungal plant pathogen (paper) Probiotics may not be helpful if one is genetically unable to respond to them Activity of gut microbes can affect nervous system inflammation Biofilms develop good electrical conductivity (paper) Three ways antibiotics affect more than just infections Post questions or comments here or email to bacteriofiles at gmail dot com. Thanks for listening! Subscribe at iTunes or Google Play, support the show at Patreon, or check out the show at Twitter or Facebook

This episode: Some bacteria seem to cause slime mold amoebas to carry around other bacteria for food! Download Episode (12.4 MB, 13.5 minutes) Show notes: News item Journal Paper: DiSalvo S, Haselkorn TS, Bashir U, Jimenez D, Brock DA, Queller DC, Strassmann JE. 2015. Burkholderia bacteria infectiously induce the proto-farming symbiosis of Dictyostelium amoebae and food bacteria. Proc Natl Acad Sci 112:E5029–E5037. Other interesting stories: Fish oil vs. lard affect gut microbes differently Engineered mix of engineered bacteria produce controlled oscillations Mutation and selection makes better biomass-degrading enzymes Antibodies can be produced inside bacteria (paper) Fungus can be used to kill mosquitoes (paper) Post questions or comments here or email to bacteriofiles at gmail dot com. Thanks for listening! Subscribe at iTunes, check out the show at Twitter or Facebook

This episode: Amoebas in soil gang up on and eat much larger roundworms! Download Episode (10.5 MB, 11.3 minutes)Show notes:Journal Paper Video of amoebas eating worm Discussion on This Week in Microbiology Other interesting stories: Fungi living inside plants produce potential anticancer compound (paper) Local bacteria help protect and nurture crops in Nigeria (paper) Squished bacteria grow as pancake-shaped cells (paper) Bacteria living in fungi that help plants have many genes taken from their hosts (paper) Engineering yeast that produce opiates cheaply Post questions or comments here or email to bacteriofiles at gmail dot com. Thanks for listening! Subscribe at iTunes, check out the show at Twitter or Facebook

The highly conserved protein actin is the building block in the cytoskeleton of eukaryotic cells and provides a structural framework known as the microfilament system.The molecular principle of actin-based amoeboid movement was so successful in evolution that it was kept nearly identically from lower (e.g. amoebae) to higher (e.g. neutrophils) eukaryotes.To understand this type of cellular movement one has first to identify and to characterize the proteins which play a major role during the dynamic rearrangement of actin. The collection of actin isoforms, of actin-variants and actin related proteins (Arps) in a given cell is known as the 'actinome' whose number of proteins can be quite different from one organism to the next. Therefore, the present work describes studies on the actinome of thesocial amoeba Dictyostelium discoideum, compares the findings with actinomes from other organisms, and discusses similarities and alterations that might have happened during evolution. D. discoideum is among the oldest organisms which exhibit actin-based amoeboid movement, the genome is completely sequenced and the system can be easily studied by molecular and biochemical approaches. The study was started using bioinformatics and the computational methods provided a global view on the D. discoideum actinome. It turned out that the D. discoideum genome conprises a total of 33 actin and 8 Arp genes, seven actin genes are putative pseudogenes. Interestingly, there are 17 distinguishable actin genes which code for identical proteins. Phylogenetic analyses helped to understand the putative duplication events during evolution. Modelling of the three-dimensional structures showed that the typical actin-fold, the ATP-binding pocket, and other functional domains are highly conserved. Homologues of the members of the D. discoideum actinome across various model organisms clearly demonstrated which amino acids in conserved domains are of special importance. All Arp subfamilies that are found in mammals are also present in D. discoideum. Two of the actin related proteins, Arp5 and Arp6, were selected for molecular and cellular studies. Using fluorescently labeled fusion proteins first data indicated that both Arps are present also in the nucleus, suggesting an involvement in chromatin reorganization.

This episode: Slime mold cells carry bacteria with them, some for food and some for chemical warfare! Download Episode (6.4 MB, 7 minutes)Show notes:News item 1/News item 2/Journal Paper Other interesting stories: Vaccines using Salmonella could now pass through the stomach, becoming more effective C-section might not be as good for infants' gut communities Useful RNA-based technique for modifying biotech cells' metabolism Protein allows gut cells to tolerate good bacteria and depend on them for protection from pathogens Bacteria may be better way to clean chemicals from water supply Post questions or comments here or email to bacteriofiles at gmail dot com. Thanks for listening! Subscribe at iTunes, check out the show at Twitter or Facebook

This episode: New giant virus discovered, with a genome larger than that of some eukaryotes! Download Episode (7.5 MB, 8.1 minutes)Show notes:News item 1/News item 2/News item 3/News item 4/Journal Paper Other interesting stories: Using bacteria as factories to produce drugs, originally found in plants, cheaply Ocean bacteria can "see" by sensing the color of light and adjusting their behavior Though many gut viruses are stable, some change rapidly over time Reducing need for fertilizer by creating artificial plant-bacteria symbioses Fungal symbionts help plants tolerate heat and drought (paper) Post questions or comments here or email to bacteriofiles at gmail dot com. Thanks for listening! Subscribe at iTunes, check out the show at Twitter or Facebook

Here's my summary of the fourth and final day of ASM2013, with a special surprise guest appearance at the end! Download Episode (5.5 MB, 6 minutes) Session 1: Synthetic Genomics to Create a Minimal Bacterial Cell and Some Other Neat Stuff Presented by John I. Glass He talked about the cell with the synthetic genome (full episode 13), and about how important it is to determine what is the minimal amount of genome a cell needs to grow--knowing that, you can start there and build almost anything you want. He also talked about a new method of producing new flu strains for vaccine production using synthetic nucleic acids, which could greatly shorten the time it takes to get a new vaccine going to counter a pandemic. Session 2: C. difficile vs. the Microbiota: The Enemy of My Enemy is My Friend Presented by Shonna McBride When a probiotic (Lactococcus lactis) was grown with C. difficile, the latter was killed. Session 3: An Intriguing Bacterial Symbiont in the Nucleus of Amoebae Presented by Frederik SchulzInteractions between amoebae and bacteria are interesting and also relevant to our health, considering the similarities between amoebae and cells of our immune system. This interaction is particularly interesting: bacteria living inside the nucleus. Post questions or comments here or email to bacteriofiles at gmail dot com. Thanks for listening! Subscribe at iTunes, check out the show at Twitter or Facebook

This episode: Amoebae snag pathogenic bacteria in soil and carry them around as a portable snack! Download Episode (3.9 MB, 4.25 minutes)Show notes:Journal Paper /Video Other interesting stories: Bacteria could be used to produce pleasing scents Plant-dwelling bacteria with particular enzyme could help cut flowers last longer (paper) Fragile bacterial crusts are important for desert ecosystems Bacteria could protect frogs from deadly fungus plague How bacteria help animals eat grass Post questions or comments here or email to bacteriofiles at gmail dot com . Thanks for listening! Subscribe at iTunes, check out the show at Twitter or SciencePodcasters.org

This episode: Slime molds farm their own bacterial food! Download Episode (4.4 MB, 4.75 minutes)Show notes:News item 1/News item 2/Journal paper Other interesting stories: Some bacteria could probably survive on Mars Trying to keep our space travels from contaminating Mars How bacteria bore into sea shells Extracellular DNA is an important part of bacterial biofilms Engineering cheese-maker into fuel producer How aerial microbes affect everything Post questions or comments here or email to bacteriofiles at gmail dot com This e-mail address is being protected from spambots. You need JavaScript enabled to view it . Thanks for listening! Subscribe at iTunes, check out the show at Twitter or SciencePodcasters.org

Dictyostelium, an amoeboid motile cell, harbors several paralogous Sec7 genes that encode members of three distinct subfamilies of the Sec7 superfamily of Guanine nucleotide exchange factors. Among them are proteins of the GBF/BIG family present in all eukaryotes. The third subfamily represented with three members in D. discoideum is the cytohesin family that has been thought to be metazoan specific. Cytohesins are characterized by a Sec7 PH tandem domain and have roles in cell adhesion and migration. Dictyostelium SecG exhibits highest homologies to the cytohesins. It harbors at its amino terminus several ankyrin repeats that are followed by the Sec7 PH tandem domain. Mutants lacking SecG show reduced cell-substratum adhesion whereas cell-cell adhesion that is important for development is not affected. Accordingly, multicellular development proceeds normally in the mutant. During chemotaxis secG(-) cells elongate and migrate in a directed fashion towards cAMP, however speed is moderately reduced. The data indicate that SecG is a relevant factor for cell-substrate adhesion and reveal the basic function of a cytohesin in a lower eukaryote.

On episode #63 of the podcast This Week in Virology, Vincent, Alan, and Rich talk about US government contract for freeze-dried smallpox vaccine, red squirrels in the UK threatened by poxvirus, and Marseillevirus, another DNA virus from amoebae built for comfort and speed. Host links Vincent Racaniello, Alan Dove, and Rich Condit Links for this episode: US Government awards contract to Bavarian Nordic for freeze-dried smallpox vaccine (pdf and clinical trial) UK red squirrels threatened by poxvirus: news article one and two,epidemiologyand experimental infection Another huge virus from amoebae (Wired article, PNASarticle, review article) Discussion on rabies bait vaccine at virology blog, and status of the program Viral diseases of humans (pdf)