Pseudomonas aeruginosa Mobbing-Like Behavior against Acanthamoeba castellanii Bacterivore and Its Rapid Control by Quorum Sensing and Environmental Cues

Pseudomonas aeruginosa was shown previously to attack amoebae and other predators by adhering to them and injecting them with virulent substances. In this work, we show that an active, coordinated group behavior is enacted by the bacteria to utilize these molecular components, responding to both predator and bacterial population density.

The use of mild viruses for control of plant pathogenic viruses

Plant virus management strategies have largely been limited to the application of hygiene protocols, the control of viral vectors such as insects and nematodes and the use of resistant varieties. However, these approaches are often insufficient to prevent infections. The rapid control of newly emerging viral diseases remains challenging. This chapter focuses on cross-protection using mild viruses as active substances in biocontrol. The chapter begins by describing the theoretical modes of action of cross-protection. It then goes on to discuss crucial elements in the development of a cross-protection strategy, taking into account new insights based on commercial application of cross-protection. The chapter also provides case studies in which cross-protection has been applied in commercial crops, in particular vaccination strategies to control Pepino mosaic virus (PepMV) in greenhouse tomato. Finally, developments that may impact future research into the control of emerging viral pathogens are discussed.

Rapid surveillance platforms for key SARS-CoV-2 mutations in Denmark

Multiple mutations in SARS-CoV-2 variants of concern (VOCs) may increase, transmission, disease severity, immune evasion and facilitate zoonotic or anthoprozoonotic infections. Four such mutations, ΔH69/V70, L452R, E484K and N501Y, occur in the SARS-CoV-2 spike glycoprotein in combinations that allow detection of the most important VOCs. Here we present two flexible RT-qPCR platforms for small- and large-scale screening to detect these mutations, and schemes for adapting the platforms for future mutations. The large-scale RT-qPCR platform, was validated by pair-wise matching of RT-qPCR results with WGS consensus genomes, showing high specificity and sensitivity. Detection of mutations using this platform served as an important interventive measure for the Danish public health system to delay the emergence of VOCs and to gain time for vaccine administration. Both platforms are valuable tools for WGS-lean laboratories, as well for complementing WGS to support rapid control of local transmission chains worldwide.

Emergence of SARS-CoV-2 variant B.1.575.2 containing the E484K mutation in the spike protein in Pamplona (Spain) May-June 2021

With the emergence of new SARS-CoV-2 variants and the acquisition of novel mutations in exiting lineages, the need to implement methods capable of monitoring viral dynamics arises. We report the emergence and spread of a new SARS-CoV-2 variant within B.1.575 lineage containing the E484K mutation in the spike protein (named B.1.575.2) in a region of Northern Spain between May and June 2021. SARS-CoV-2 positive samples with cycle threshold value less than or equal to 30 were selected to screen of presumptive variants using the TaqPath TM COVID-19 RT-PCR kit and TaqMan TM SARS-CoV-2 Mutation Panel. Confirmation of variants was performed by whole genome sequencing. Of the 200 samples belonging to the B.1.575 lineage, 194 (97%) corresponded to the B.1.575.2 sub-lineage, which was related to the presence of the E484K mutation. Of 197 cases registered in GISAID EpiCoV database as lineage B.1.575.2, 194 (99.5%) were identified in Pamplona (Spain) This report emphasizes the importance of complementing surveillance of SARS-CoV-2 with sequencing for the rapid control of emerging viral variants.

Efficacy and breadth of adjuvanted SARS-CoV-2 receptor-binding domain nanoparticle vaccine in macaques

Emergence of novel variants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) underscores the need for next-generation vaccines able to elicit broad and durable immunity. Here we report the evaluation of a ferritin nanoparticle vaccine displaying the receptor-binding domain of the SARS-CoV-2 spike protein (RFN) adjuvanted with Army Liposomal Formulation QS-21 (ALFQ). RFN vaccination of macaques using a two-dose regimen resulted in robust, predominantly Th1 CD4+ T cell responses and reciprocal peak mean serum neutralizing antibody titers of 14,000 to 21,000. Rapid control of viral replication was achieved in the upper and lower airways of animals after high-dose SARS-CoV-2 respiratory challenge, with undetectable replication within 4 d in seven of eight animals receiving 50 µg of RFN. Cross-neutralization activity against SARS-CoV-2 variant B.1.351 decreased only approximately twofold relative to WA1/2020. In addition, neutralizing, effector antibody and cellular responses targeted the heterotypic SARS-CoV-1, highlighting the broad immunogenicity of RFN-ALFQ for SARS-CoV−like Sarbecovirus vaccine development.