Methanosarcina Spherical Virus, a Novel Archaeal Lytic Virus Targeting Methanosarcina Strains

Abstract

A novel archaeal lytic virus targeting species of the genus was isolated using strain Gö1 as the host. Due to its spherical morphology, the virus was designated hanosarcinapherical irus (MetSV). Molecular analysis demonstrated that MetSV contains double-stranded linear DNA with a genome size of 10,567 bp containing 22 open reading frames (ORFs), all oriented in the same direction. Functions were predicted for some of these ORFs, i.e., such as DNA polymerase, ATPase, and DNA-binding protein as well as envelope (structural) protein. MetSV-derived spacers in CRISPR loci were detected in several published draft genomes using bioinformatic tools, revealing a potential protospacer-adjacent motif (PAM) motif (TTA/T). Transcription and expression of several predicted viral ORFs were validated by reverse transcription-PCR (RT-PCR), PAGE analysis, and liquid chromatography-mass spectrometry (LC-MS)-based proteomics. Analysis of core lipids by atmospheric pressure chemical ionization (APCI) mass spectrometry showed that MetSV and both contain archaeol and glycerol dialkyl glycerol tetraether without a cyclopentane moiety (GDGT-0). The MetSV host range is limited to strains growing as single cells (, and). In contrast, strains growing as sarcina-like aggregates were apparently protected from infection. Heterogeneity related to morphology phases in cultures allowed acquisition of resistance to MetSV after challenge by growing cultures as sarcina-like aggregates. CRISPR/Cas-mediated resistance was excluded since neither of the two CRISPR arrays showed MetSV-derived spacer acquisition. Based on these findings, we propose that changing the morphology from single cells to sarcina-like aggregates upon rearrangement of the envelope structure prevents infection and subsequent lysis by MetSV. Methanoarchaea are among the most abundant organisms on the planet since they are present in high numbers in major anaerobic environments. They convert various carbon sources, e.g., acetate, methylamines, or methanol, to methane and carbon dioxide; thus, they have a significant impact on the emission of major greenhouse gases. Today, very little is known about viruses specifically infecting methanoarchaea that most probably impact the abundance of methanoarchaea in microbial consortia. Here, we characterize the first identified -infecting virus (MetSV) and show a mechanism for acquiring resistance against MetSV. Based on our results, we propose that growth as sarcina-like aggregates prevents infection and subsequent lysis. These findings allow new insights into the virus-host relationship in methanogenic community structures, their dynamics, and their phase heterogeneity. Moreover, the availability of a specific virus provides new possibilities to deepen our knowledge of the defense mechanisms of potential hosts and offers tools for genetic manipulation.

Docking protein-1 promotes inflammatory macrophage signaling in gastric cancer

“…DOK1/2 regulate development and function of NK, 50 γδ NK/ T, 51 memory 52 and virus-specific CD8 + T-cells. 53 Cytotoxic NK/T cells and macrophages secrete interferons, granzymes, nitric oxide and tumor necrosis factor-alpha (TNFα), and may thus be useful for launching anti-tumor responses. Further emphasizing an activatory function of DOK1 in innate immune cells, including macrophages, DOK1 has been shown to be integrated in pathogen-sensing receptor complexes facilitating host susceptibility towards infections by viruses, parasites, and bacteria, e.g., for Pseudomonas aeruginosa 54 or Helicobacter pylori.…”

Computationally optimized broadly reactive vaccine based upon swine H1N1 influenza hemagglutinin sequences protects against both swine and human isolated viruses

“…The COBRA method uses multiple rounds of consensus building based upon not only the phylogenetic sequence of each isolate, but also the outbreak and specific time that each isolate was collected, thereby eliminating the bias in the number of sequences uploaded to online databases. Previously, our group has demonstrated the effectiveness of the COBRA HA antigens for H5N1, 14,15 H3N2, [53][54][55] and H1N1 against human seasonal and pandemic influenza viruses. 17 These H1N1 COBRA HA proteins (X3, X6, and P1) elicited antibodies with HAI activity against a range of Figure 9.…”

sRNA41 affects ribosome binding sites within polycistronic mRNAs in Methanosarcina mazei Gö1

“…In both cases, the mutation did not result in a significant growth phenotype, neither for nitrogen sufficiency nor for nitrogen limiting growth conditions (data not shown). Furthermore, determining transcript levels in Mm_Ds41 and Mm_OPs41 using established genomic microarrays (Weidenbach et al, 2017) in combination with qRT-PCR analysis of selected genes (Table 1) generally showed no significant changes in transcript levels ( twofold, for selected genes and ACDS operon see Table 1 and Supporting Information Fig. S4A).…”

“…RNA of M. mazei mutants purified for microarray analysis was reverse transcribed into cDNA and simultaneously labeled with Cy5 and Cy3 respectively, using the CyScribe First-Strand cDNA Labeling Kit (GE Healthcare) according to the manufacturer's protocol. Microarray experiments and analysis of three biological replicates was performed as described previously (Weidenbach et al, 2017).qRT-PCR assays were performed and analyzed as described in but using the QuantiTect SYBR Green RT-PCR Kit (Qiagen, Hilden, Germany) and the ViiA TM 7 Real-Time PCR System (Applied Biosystems, Foster City, CA, USA). Gene expression level of three biological replicates was calculated using the normalizing 2 -DDCt value.…”