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Other Double-Stranded DNA Viruses
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
As reviewed by Claverie and Abergel (2018), the Mimiviridae family exhibited the broadest distribution of genome sizes, from 370 kb for Aureococcus anophagefferens virus (AaV) to 1.51 Mb for Tupanvirus deep Ocean (TupanDO, or TPV-DO), as well as of particle sizes (from 750–140 nm for icosahedral virions, up to 2.3 µm for the tailed tupanviruses). About tupanviruses and the proposed genus Tupanvirus see Rodrigues et al. (2019). Despite these huge differences, all members of the family demonstrated similar architecture of particles, including an internal lipid membrane. Figure 5.6. demonstrates a portrait of Acanthamoeba polyphaga mimivirus (APMV), a reference strain of the Mimivirus genus. However, the technical barriers have prevented high-resolution reconstructions of APMV (Xiao et al. 2009).
Therapeutic Approach in Fungal Keratitis
Published in Mahendra Rai, Marcelo Luís Occhiutto, Mycotic Keratitis, 2019
Victoria Díaz-Tome, María Teresa-Rodríguez Ares, Rubén Varela-Fernández, Rosario Touriño-Peralba, Miguel González-Barcia, Laura Martínez-Pérez, María Jesús Lamas, Francisco J. Otero-Espinar, Anxo Fernández-Ferreiro
Polyhexamethylene biguanide (PHMB), also known as polyhexanide, polyaminopropyl biguanide, polymeric biguanide hydrochloride or polyhexanide biguanide, is an antiseptic with antiviral and antibacterial properties used as an alternative for fungal keratitis treatment. It also shows a broad viricide and antifungal spectrum and has amoebicidal activity. Certainly, its antimicrobial efficacy has been demonstrated on Acanthamoeba polyphaga, A. castellanii, and A. hatchetti (Asiedu-Gyekye et al. 2015) by using 0.02 to 0.053% solutions without causing side effects.
Miconazole
Published in M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson, Kucers’ The Use of Antibiotics, 2017
The growth of Naegleria fowleri, the cause of primary amebic meningoencephalitis in humans, is suppressed in vitro by miconazole (Thong et al., 1977). Acanthamoeba polyphaga and A. castellanii may be susceptible in vitro to miconazole, but there are reports of little or no activity of this agent against trophozoites or cysts of acanthamoebae (Nagington and Richards, 1976; Kilvington et al., 1990). Miconazole has been shown to inhibit the growth of Trichomonas vaginalis to a similar degree to ketoconazole and metronidazole (Sugarman and Mummaw, 1988). Finally, miconazole is active against chloroquine-sensitive and chloroquine-resistant Plasmodium falciparum parasites (Pfaller and Krogstad, 1981).
Consequences and repair of radiation-induced DNA damage: fifty years of fun questions and answers
Published in International Journal of Radiation Biology, 2022
Unlike cellular organisms, DNA repair proteins are not very well-conserved in viruses, presumably due to their small genomes. However, the Mimivirus (short for mimicking microbe), a double stranded DNA virus that infects Acanthamoeba polyphaga, has a genome size of 1.2 megabases with six genes that code for DNA repair enzymes. Vishy Bandaru, a post-doc in my lab, cloned, expressed and purified two of these, MvNei1 and MvNei2, homologs of the human NEIL proteins (Bandaru et al. 2007). Both recognize oxidized pyrimidines in duplex DNA and in bubble structures and MvNei2 also removes lesions from single stranded DNA. The lyase activity of MvNei1 cleaves the DNA by ß,δ-elimination while MvNei2 lyase cleaves the DNA by ß-elimination. Like NEIL1, MvNei1 contains an anti-parallel ß-hairpin ‘zincless finger’ motif while MvNei2 contains a zinc finger motif like human NEIL2. Also, MvNei2 resembles human NEIL3 at the N-terminus and NEIL2 at the C-terminus.
Current understanding and therapeutic management of contact lens associated sterile corneal infiltrates and microbial keratitis
Published in Clinical and Experimental Optometry, 2021
Lily Ho, Isabelle Jalbert, Kathleen Watt, Alex Hui
For contact lens-related MK, the majority of infections are due to Pseudomonas aeruginosa.28 This is followed by Gram-positive bacteria, fungi, and Acanthamoeba species, respectively.28 For nontherapeutic contact lens wearers, the most commonly isolated fungal organism in fungal keratitis is Fusarium (filamentary fungi), followed by Aspergillus (filamentary fungi);29 in contrast, in therapeutic contact lens wearers, Candida (yeast) and Fusarium are most commonly isolated causative fungal keratitis organisms.29 Although microsporidia keratoconjunctivitis has been found in contact lens wearers, it is usually associated with soil or mud and occurs in immunocompromised patients.30 The majority of strains causing either non-contact lens associated or contact lens-associated Acanthamoeba keratitis have been shown to exhibit the T4 genotype, which includes species Acanthamoeba castellanii, Acanthamoeba polyphaga, and Acanthamoeba culbertsonii.31
The rumen microbiome: a crucial consideration when optimising milk and meat production and nitrogen utilisation efficiency
Published in Gut Microbes, 2019
Chloe Matthews, Fiona Crispie, Eva Lewis, Michael Reid, Paul W. O’Toole, Paul D. Cotter
Amoebae can represent an important reservoir for bacteria in the environment, but their role in the rumen is unclear. In the vegetative cycle (multiplication by binary fission), amoeba, similar to ciliate protozoa, survive by ingesting bacteria through phagocytosis.51 While further research is necessary in order to ascertain the role of amoeba in the rumen, it is known that some bacteria can survive phagocytosis by protozoa and live as endosymbionts.52 For instance, Campylobacter jejuni has been shown to invade Acanthamoeba polyphaga and can replicate in vacuoles.53C. jejuni and C. fetus can have large effects on cow fertility, immunity and overall health.54 Amoeba therefore may be important in rumen and general bovine health.