Acanthamoeba polyphaga mimivirus Stability in Environmental and Clinical Substrates: Implications for Virus Detection and Isolation

Abstract

Viruses are extremely diverse and abundant and are present in countless environments. Giant viruses of the Megavirales order have emerged as a fascinating research topic for virologists around the world. As evidence of their ubiquity and ecological impact, mimiviruses have been found in multiple environmental samples. However, isolation of these viruses from environmental samples is inefficient, mainly due to methodological limitations and lack of information regarding the interactions between viruses and substrates. In this work, we demonstrate the long-lasting stability of mimivirus in environmental (freshwater and saline water) and hospital (ventilator plastic device tube) substrates, showing the detection of infectious particles after more than 9 months. In addition, an enrichment protocol was implemented that remarkably increased mimivirus detection from all tested substrates, including field tests. Moreover, biological, morphological and genetic tests revealed that the enrichment protocol maintained mimivirus particle integrity. In conclusion, our work demonstrated the stability of APMV in samples of environmental and health interest and proposed a reliable and easy protocol to improve giant virus isolation. The data presented here can guide future giant virus detection and isolation studies.

Cedratvirus lausannensis – digging into Pithoviridae diversity

“…Interestingly, C. lausannensis presents a high resistance to selected inactivation treatments, including ethanol and hydrogen peroxide. It has been reported that other amoeba‐infecting viruses such as Acanthamoeba polyphaga mimivirus (APMV) are able to survive in various environmental and clinical substrates (Dornas et al ., ). This could become a concern since it has also been suggested that APMV as well as other amoebae‐infecting viruses that belong to Marseilleviridae could be associated with human infections (La Scola, ; Aherfi et al ., ).…”

Oysters as hot spots for mimivirus isolation

“…Briefly, Acanthamoeba castellanii were infected at an m.o.i. of 0.01 for 36 hours and then fixed with 2.5 % glutaraldehyde (Merck, Germany) for one hour before visualization by electron microscopy, ultrathin sections were prepared and analyzed at the Centro de Microscopia, UFMG, Brazil [10]. Images of our samples revealed the presence of typical mimiviruslike particles, with sizes ranging between 500 and 700 nm ( Fig.…”

“…1A and Table 1. In order to increase the efficiency of virus recovery, samples were subjected to an enrichment process [10]. After this procedure, total DNA was extracted from the samples by the phenol-chloroform method and used as template for real-time PCR assays targeting the conserved helicase gene (primers: 5 0 -ACCTGATCCACATCCCATAACTAAA-3 0 and 5 0 -GGCCTCATCAACAAATGGTTTCT-3 0 ), using a SYBR Green Master Mix (Applied Biosystems, USA) in 10-lL reactions.…”

“…In parallel, samples were also used for an isolation assay in Acanthamoeba castellanii (ATCC 30010) monolayers. A total of three blind passages were performed, and samples showing a cytopathic effect were collected, titrated using the TCID 50 method and analyzed by transmission electron microscopy (TEM) and qPCR [10]. Also, to characterize those isolates biologically, representative viral samples from each studied area were used to make one-step-growth curves and analyzed by polyacrylamide gel electrophoresis (PAGE) [3].…”

Boiling Acid Mimics Intracellular Giant Virus Genome Release

“…GV are ubiquitous (Aherfi et al, 2016b;Andrade et al, 2018) and maintain infectivity in harsh environments such as alkaline lakes , frozen permafrost (Legendre et al, 2014), 3 km deep in the ocean and dry valleys in Antarctica Kerepesi and Grolmusz, 2017). GV have retained infectivity following exposure to harsh chemicals (Campos et al, 2012), extreme pH and salinity , extreme temperatures Legendre et al, 2014), and are able to persist on hospital equipment (Campos et al, 2012;Dornas et al, 2014b). To survive such extremes, GV have developed incredible capsid stability.…”