Reconceptualizing transcriptional slippage in plant RNA viruses.

RNA viruses have evolved sophisticated strategies to exploit the limited encoded information within their typically compact genomes. One of them, named transcriptional slippage (TS), is characterized by the appearance of indels in nascent viral RNAs, leading to changes in the open reading frame (ORF). Although members of unrelated viral families express key proteins via TS, the available information about this phenomenon is still limited. In potyvirids (members of the Potyviridae family), TS has been defined by the insertion of an additional A at An motifs (n ≥ 6) in newly synthesized transcripts at a low frequency, modulated by nucleotides flanking the A-rich motif. Here, by using diverse experimental approaches and a collection of plant/virus combinations, we discover cases not following this definition. In summary, we observe (i) a high rate of single-nucleotide deletions at slippage motifs, (ii) overlapping ORFs acceded by slippage at an U8 stretch, and (iii) changes in slippage rates induced by factors not related to cognate viruses. Moreover, a survey of whole-genome sequences from potyvirids shows a widespread occurrence of species-specific An/Un (n ≥ 6) motifs. Even though many of them, but not all, lead to the production of truncated proteins rather than access to overlapping ORFs, these results suggest that slippage motifs appear more frequently than expected and play relevant roles during virus evolution. Considering the potential of this phenomenon to expand the viral proteome by acceding to overlapping ORFs and/or producing truncated proteins, a re-evaluation of TS significance during infections of RNA viruses is required.IMPORTANCETranscriptional slippage (TS) is used by RNA viruses as another strategy to maximize the coding information in their genomes. This phenomenon is based on a peculiar feature of viral replicases: they may produce indels in a small fraction of newly synthesized viral RNAs when transcribing certain motifs and then produce alternative proteins due to a change of the reading frame or truncated products by premature termination. Here, using plant-infecting RNA viruses as models, we discover cases expanding on previously established features of plant virus TS, prompting us to reconsider and redefine this expression strategy. An interesting conclusion from our study is that TS might be more relevant during RNA virus evolution and infection processes than previously assumed.

Enhanced Susceptibility to Tomato Chlorosis Virus (ToCV) in Hsp90- and Sgt1-Silenced Plants: Insights from Gene Expression Dynamics.

The emerging whitefly-transmitted crinivirus tomato chlorosis virus (ToCV) causes substantial economic losses by inducing yellow leaf disorder in tomato crops. This study explores potential resistance mechanisms by examining early-stage molecular responses to ToCV. A time-course transcriptome analysis compared naïve, mock, and ToCV-infected plants at 2, 7, and 14 days post-infection (dpi). Gene expression changes were most notable at 2 and 14 dpi, likely corresponding to whitefly feeding and viral infection. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed key genes and pathways associated with ToCV infection, including those related to plant immunity, flavonoid and steroid biosynthesis, photosynthesis, and hormone signaling. Additionally, virus-derived small interfering RNAs (vsRNAs) originating from ToCV predominantly came from RNA2 and were 22 nucleotides in length. Furthermore, two genes involved in plant immunity, Hsp90 (heat shock protein 90) and its co-chaperone Sgt1 (suppressor of the G2 allele of Skp1) were targeted through viral-induced gene silencing (VIGS), showing a potential contribution to basal resistance against viral infections since their reduction correlated with increased ToCV accumulation. This study provides insights into tomato plant responses to ToCV, with potential implications for developing effective disease control strategies.

cmv1-Mediated Resistance to CMV in Melon Can Be Overcome by Mixed Infections with Potyviruses.

Resistance to cucumber mosaic virus (CMV) strain LS in melon is controlled by the gene cmv1, which restricts phloem entry. In nature, CMV is commonly found in mixed infections, particularly with potyviruses, where a synergistic effect is frequently produced. We have explored the possibility that this synergism could help CMV-LS to overcome cmv1-mediated resistance. We demonstrate that during mixed infection with a potyvirus, CMV-LS is able to overcome cmv1-controlled resistance and develop a systemic infection and that this ability does not depend on an increased accumulation of CMV-LS in mechanically inoculated cotyledons. Likewise, during a mixed infection initiated by aphids, the natural vector of both cucumoviruses and potyviruses that can very efficiently inoculate plants with a low number of virions, CMV-LS also overcomes cmv1-controlled resistance. This indicates that in the presence of a potyvirus, even a very low amount of inoculum, can be sufficient to surpass the resistance and initiate the infection. These results indicate that there is an important risk for this resistance to be broken in nature as a consequence of mixed infections, and therefore, its deployment in elite cultivars would not be enough to ensure a long-lasting resistance.

Microbial community on industrial salty bovine hides: From the slaughterhouse to the salting.

The leather-making industry is an age-old industry and desiccation with salt has been one of the most used methodologies for obtaining valuable skins. However, halophiles may proliferate and affect the integrity of the hide-collagen structure, as well as leading to undesirable red colorations or less-frequent purple stains. To understand the basis of these industrial hide contaminations, the microbial community from raw hide samples, salt-cured samples and four different industrial salts, was analyzed by 16S rRNA gene metabarcoding together with standard cultivation methods. Comparison of raw hides and correctly cured hides revealed a core microbiome that was absent from contaminated hides. In addition, archaea were missing from well-cured hides, whereas Psychrobacter and Acinetobacter were highly represented (23 % and 17.4 %, respectively). In damaged hides, only a few operational taxonomic units (OTUs), from among the hundreds detected, were able to proliferate and, remarkably, a single Halomonas OTU represented 57.66 % of the reads. Halobacteria, mainly Halovenus, Halorubrum and Halovivax, increased by up to 36.24-39.5 % in the red- and purple-affected hides. The major contaminants were isolated and hide infections, together with collagenase activity, were evaluated. The results showed that hides enriched with the non-pigmented isolate Halomonas utahensis COIN160 damaged the collagen fibers similarly to Halorubrum, and together they were considered to be one of the major causes. Putative degrading inhibitors were also identified from among the Alkalibacillus isolates. It was concluded that hide contaminations were driven by clonal outbreaks of a few specific microbes, which may have been non-pigmented collagen degraders. Acinetobacter and Alkalibacillus, members of the core microbiome of raw and well-cured salted hides, are suggested as hide contaminant inhibitors that need further analysis.

CryoEM and stability analysis of virus-like particles of potyvirus and ipomovirus infecting a common host.

Sweet potato feathery mottle virus (SPFMV) and Sweet potato mild mottle virus (SPMMV) are members of the genera Potyvirus and Ipomovirus, family Potyviridae, sharing Ipomoea batatas as common host, but transmitted, respectively, by aphids and whiteflies. Virions of family members consist of flexuous rods with multiple copies of a single coat protein (CP) surrounding the RNA genome. Here we report the generation of virus-like particles (VLPs) by transient expression of the CPs of SPFMV and SPMMV in the presence of a replicating RNA in Nicotiana benthamiana. Analysis of the purified VLPs by cryo-electron microscopy, gave structures with resolutions of 2.6 and 3.0 Å, respectively, showing a similar left-handed helical arrangement of 8.8 CP subunits per turn with the C-terminus at the inner surface and a binding pocket for the encapsidated ssRNA. Despite their similar architecture, thermal stability studies reveal that SPMMV VLPs are more stable than those of SPFMV.

Fluid administration in cytoreductive surgery with hyperthermic intraperitoneal chemotherapy: neither too much nor too little

Abstract Introduction Intraoperative fluid therapy in cytoreductive surgery with hyperthermic intraperitoneal chemotherapy plays an important role in postoperative morbidity. Studies have found an association between overload fluid therapy and increased postoperative complications, advising restrictive intraoperative fluid therapy. Our objective in this study was to compare the morbidity associated with restrictive versus non-restrictive intraoperative fluid therapy. Methods Retrospective analysis of a database collected prospectively in the Anesthesiology Service of Virgen del Rocío Hospital, from December 2016 to April 2019. One hundred and six patients who underwent complete cytoreductive surgery and hyperthermic intraperitoneal chemotherapy were divided into two cohorts according to Fluid Therapy received 1. Restrictive ≤ 9 mL.kg-1.h-1 (34 patients), 2. Non-restrictive ≥ 9 mL.kg-1.h-1 (72 patients). Percentage of major complications (Clavien-Dindo grade III-IV) and length hospital stay were the main outcomes variables. Results Of the 106 enrolled patients, 68.9% were women; 46.2% had ovarian cancer, 35.84% colorectal cancer, and 7.5% peritoneal cancer. The average fluid administration rate was 11 ± 3.58 mL.kg-1.h-1. The restrictive group suffered a significantly higher percentage of Clavien-Dindo grade III-IV complications (35.29%) compared with the non-restrictive group (15.27%) (p= 0.02). The relative risk associated with restrictive therapy was 1.968 (95% confidence interval: 1.158-3.346). We also found a significant difference for hospital length of stay, 20.91 days in the restrictive group vs 16.19 days in the non-restrictive group (p= 0.038). Conclusions Intraoperative fluid therapy restriction below 9 mL.kg-1.h-1 in cytoreductive surgery with hyperthermic intraperitoneal chemotherapy was associated with a higher percentage of major postoperative complications.

New definitions of susceptibility categories EUCAST 2019: clinic application

In January 2019, the European Committee for the Study of Antimicrobial Susceptibility (EUCAST) introduced some changes in the definitions of clinical categories for antibiotic susceptibility. The objective of these changes was to improve the credibility of category “I”, optimizing and lengthening the survival and use of available antibiotics in the face of increasing antimicrobial resistance. This article aims to describe and explain these changes in the EUCAST criteria as well as make a short review about the factors on which the antibiotic susceptibility criteria depend. (AU)

ICTV Virus Taxonomy Profile: Potyviridae 2022.

The family Potyviridae includes plant viruses with single-stranded, positive-sense RNA genomes of 8-11 kb and flexuous filamentous particles 650-950 nm long and 11-20 nm wide. Genera in the family are distinguished by the host range, genomic features and phylogeny of the member viruses. Most genomes are monopartite, but those of members of the genus Bymovirus are bipartite. Some members cause serious disease epidemics in cultivated plants. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the family Potyviridae, which is available at ictv.global/report/potyviridae.

Ideological Influences on Intergroup Attitudes in the Context of the Hague Court Boundary Dispute between Peru and Chile / Influencias ideológicas de las actitudes intergrupales en el contexto de la disputa fronteriza entre Perú y Chile ante la Corte de la Haya / Influências ideológicas das atitudes intergrupais no contexto da disputa fronteiriça entre Peru e Chile frente à Corte de Haia

Abstract In the context of the border dispute presented by Peru against Chile in the The Hague Court, this study analyzes the influences of two ideological motivational dimensions: Right-Wing Authoritarianism (RWA) and Social Dominance Orientation (SDO) on a set of intergroup attitudes that involve both nations. To this end, a survey study of 196 Chileans and 223 Peruvians participants was conducted. The instruments used to measure ideology and political attitudes are the following ones: RWA Scale; SDO Scale; Scale of Intergroup attitudes between Chile-Peru and specific questions on interest in the Hague litigation and willingness to fight for one's country. The results show that in the Peruvian case attitudes of belligerence and alert and a greater willingness to fight for the country are better explained by the RWA, while in the Chilean case these same attitudes are explained both by the RWA as well as the SDO. On the other hand, pacificist attitudes are explained inversely by SDO in both countries. These findings support the hypothesis that intergroup dynamics between both countries have been marked by expressed actions of a Chilean expansionism versus a Peruvian vengefulness and suggest that equalitarianism will promote attitudes toward respect and cooperation between both groups, changing the frames of expansionism and vengefulness for one of a culture of peace.

Resumo Este estudo analisa as influências de duas dimensões motivacionais ideológicas: o Autoritarismo de Direita (RWA) e a Orientação à Dominação Social (SDO) em um conjunto de atitudes intergrupais que envolvem Perú e Chile, no contexto da disputa fronteiriça apresentada pelo primeiro contra o segundo na Corte de Haia. Para isso, foi desenvolvido um estudo com 196 participantes do Chile e 223 do Peru. Os instrumentos utilizados para medir a ideologia e as atitudes políticas são os seguintes: Questionário de RWA; questionário de SDO; questionário de atitudes intergrupos entre Chile é Peru e itens de interesse na disputa ante A Haia e a vontade de lutar pelo próprio país. Os resultados mostram que, no caso peruano, as atitudes de beligerância e alerta, e uma maior disposição de lutar pelo país são explicadas pelo RWA, enquanto no caso chileno, essas mesmas atitudes são explicadas tanto pelo RWA quanto pela SDO. Por outro lado, as atitudes pacifistas são diminuidas pela SDO nos dois países. Estos resultados corroboram á hipótese da dinâmica intergrupal entre os dois países, marcada por ações explícitas do expansionismo chileno versus revanchismo peruano; os resultados também sugerem que as ideologias igualitarias poderão promover atitudes de respeito e cooperação entre os dois grupos, alterando os esquemas expansionista e revanchista para uma cultura de paz.

Resumen En el contexto de la disputa fronteriza presentada por Perú contra Chile ante la Corte de la Haya, este estudio analiza las influencias dos dimensiones motivacionales ideológicas: el Autoritarismo de Derecha (RWA) y la Orientación a la Dominancia Social (SDO) en un conjunto de actitudes intergrupales que involucran a ambas naciones. Con esta finalidad, fue desarrollado un estudio por encuestas con 196 participantes de Chile y 223 de Perú. Los instrumentos utilizados para medir la ideología y las actitudes políticas son los siguientes: Escala de RWA; Escala de SDO; Escala de actitudes intergrupales entre Chile-Perú y preguntas específicas sobre el interés en el litigio de La Haya y la disposición de luchar por el propio país. Los resultados muestran que en el caso peruano las actitudes de beligerancia y alerta, y una mayor disposición a luchar por el país son explicadas por el RWA, mientras en el caso chileno, estas mismas actitudes son explicadas tanto por el RWA como por la SDO. Por otra parte, las actitudes pacifistas son explicadas inversamente por la SDO en ambos países. Estos hallazgos corroboran la hipótesis sobre las dinámicas intergrupales entre ambos países, las cuales han estado marcadas por acciones explicitas de expansionismo chileno versus revanchismo peruano; asimismo, los resultados sugieren que el igualitarismo promovería actitudes hacia el respeto y cooperación entre ambos grupos, cambiando los esquemas expansionista y revanchista por uno de cultura de paz.

Specificity of Resistance and Tolerance to Cucumber Vein Yellowing Virus in Melon Accessions and Resistance Breaking with a Single Mutation in VPg.

Cucumber vein yellowing virus (CVYV) is an emerging virus on cucurbits in the Mediterranean Basin, against which few resistance sources are available, particularly in melon. The melon accession PI 164323 displays complete resistance to isolate CVYV-Esp, and accession HSD 2458 presents a tolerance, i.e., very mild symptoms despite virus accumulation in inoculated plants. The resistance is controlled by a dominant allele Cvy-11, while the tolerance is controlled by a recessive allele cvy-2, independent from Cvy-11. Before introducing the resistance or tolerance in commercial cultivars through a long breeding process, it is important to estimate their specificity and durability. Upon inoculation with eight molecularly diverse CVYV isolates, the resistance was found to be isolate-specific because many CVYV isolates induced necrosis on PI 164323, whereas the tolerance presented a broader range. A resistance-breaking isolate inducing severe mosaic on PI 164323 was obtained. This isolate differed from the parental strain by a single amino acid change in the VPg coding region. An infectious CVYV cDNA clone was obtained, and the effect of the mutation in the VPg cistron on resistance to PI 164323 was confirmed by reverse genetics. This represents the first determinant for resistance-breaking in an ipomovirus. Our results indicate that the use of the Cvy-11 allele alone will not provide durable resistance to CVYV and that, if used in the field, it should be combined with other control methods such as cultural practices and pyramiding of resistance genes to achieve long-lasting resistance against CVYV.