Virus-like particles (VLPs) derived from enteric pathogens like Norwalk virus (NV) are well suited to study oral immunization. We previously described stable transgenic plants that accumulate recombinant NV-like particles (rNVs) that were orally immunogenic in mice and humans. The transgenic approach suffers from long generation time and modest level of antigen accumulation. We now overcome these constraints with an efficient tobacco mosaic virus (TMV)-derived transient expression system using leaves of Nicotiana benthamiana. We produced properly assembled rNV at 0.8 mg/g leaf 12 days post-infection (dpi). Oral immunization of CD1 mice with 100 or 250 microg/dose of partially purified rNV elicited systemic and mucosal immune responses. We conclude that the plant viral transient expression system provides a robust research tool to generate abundant quantities of rNV as enriched, concentrated VLP preparations that are orally immunogenic.

The COVID-19 pandemic forced healthcare services organization to adjust to mutating healthcare needs. Not exhaustive data are available on the consequences of this on non-COVID-19 patients. The aim of this study was to assess the impact of the pandemic on non-COVID-19 patients living in a one-million inhabitants’ area in Northern Italy (Bologna Metropolitan Area-BMA), analyzing time trends of Emergency Department (ED) visits, hospitalizations and mortality. We conducted a retrospective observational study using data extracted from BMA healthcare informative systems. Weekly trends of ED visits, hospitalizations, in- and out-of-hospital, all-cause and cause-specific mortality between December 1st, 2019 to May 31st, 2020, were compared with those of the same period of the previous year. Non-COVID-19 ED visits and hospitalizations showed a stable trend until the first Italian case of COVID-19 has been recorded, on February 19th, 2020, when they dropped simultaneously. The reduction of ED visits was observed in all age groups and across all severity and diagnosis groups. In the lockdown period a significant increase was found in overall out-of-hospital mortality (43.2%) and cause-specific out-of-hospital mortality related to neoplasms (76.7%), endocrine, nutritional and metabolic (79.5%) as well as cardiovascular (32.7%) diseases. The pandemic caused a sudden drop of ED visits and hospitalizations of non-COVID-19 patients during the lockdown period, and a concurrent increase in out-of-hospital mortality mainly driven by deaths for neoplasms, cardiovascular and endocrine diseases. As recurrencies of the COVID-19 pandemic are underway, the scenario described in this study might be useful to understand both the population reaction and the healthcare system response at the early phases of the pandemic in terms of reduced demand of care and systems capability in intercepting it.

SummaryThis paper describes two-hybrid interactions amongst barley homeodomain proteins encoded by the Three Amino acid Loop Extension (TALE) superfamily. The class I KNOX protein BKN3 is shown to homodimerise and to associate with proteins encoded by the class I and II Knox genes BKn-1 and BKn-7. Furthermore, JUBEL1 and JUBEL2, two BELL1 homologous proteins, are identi®ed and characterised as interacting partners of BKN3. Differences in the requirements of BKN3 derivatives for interactions with KNOX and JUBEL proteins imply the involvement of overlapping but slightly different domains. This set of results is an example for interactions amongst different classes of plant TALE homeodomain proteins, as previously described for related animal proteins. Apparently identical spatial and temporal expression patterns of BKn-1, BKn-3, BKn-7, JuBel1 and JuBel2, as determined by in situ hybridisation, are compatible with possible interactions of their protein products in planta. Contradictory to the common model, that the transcriptional down-regulation of certain class 1 Knox-genes is the prerequisite for organ differentiation, transcripts of all ®ve genes were, similar to Tkn1 and Tkn2/LeT6 of tomato, detected in incipient and immature leaves as well as in meristematic tissues. A characteristic phenotype is induced by the overexpression of JuBel2 in transgenic tobacco plants.

Global demand for recombinant proteins has steadily accelerated for the last 20 years. These recombinant proteins have a wide range of important applications, including vaccines and therapeutics for human and animal health, industrial enzymes, new materials and components of novel nano-particles for various applications. The majority of recombinant proteins are produced by traditional biological "factories," that is, predominantly mammalian and microbial cell cultures along with yeast and insect cells. However, these traditional technologies cannot satisfy the increasing market demand due to prohibitive capital investment requirements. During the last two decades, plants have been under intensive investigation to provide an alternative system for cost-effective, highly scalable, and safe production of recombinant proteins. Although the genetic engineering of plant viral vectors for heterologous gene expression can be dated back to the early 1980s, recent understanding of plant virology and technical progress in molecular biology have allowed for significant improvements and fine tuning of these vectors. These breakthroughs enable the flourishing of a variety of new viral-based expression systems and their wide application by academic and industry groups. In this review, we describe the principal plant viral-based production strategies and the latest plant viral expression systems, with a particular focus on the variety of proteins produced and their applications. We will summarize the recent progress in the downstream processing of plant materials for efficient extraction and purification of recombinant proteins.

Summary In the dominant mutant Hooded (K), the barley gene BKn3 is overexpressed as a result of a duplication of 305 bp in intron IV. When fused to a cauliflower mosaic virus 35S minimal promoter, the 305 bp element activates gene expression in tobacco, as does a 655 bp BKn3 promoter sequence. Both DNA fragments contain a (GA)8 repeat (GA/TC)8. A one‐hybrid screen using the 305 bp element as the DNA target led to the cloning of the barley b recombinant (BBR) protein, which binds specifically to the (GA/TC)8 repeat. BBR is nuclear targeted and is a characterized nuclear localization signal (NLS) sequence, a DNA‐binding domain extended up to 90 aa at the C‐terminus and a putative N‐terminal activation domain. The corresponding gene has no introns and is ubiquitously expressed in barley tissues. In co‐transfection experiments, BBR activates (GA/TC)8‐containing promoters, and its overexpression in tobacco leads to a pronounced leaf shape modification. BBR has properties of a GAGA‐binding factor, but the corresponding gene has no sequence homology to Trl and Psq of Drosophila, which encode functionally analogous proteins. In Arabidopsis, (GA/TC)8 repeats occur particularly within 1500 bp upstream of gene start codons included in some homeodomain genes of different classes. The data presented suggest that expression of the barley BKn3 is regulated, at least in part, by the binding of the transcription factor BBR to GA/TC repeats.