RESUMEN

BACKGROUND: Plastid genomes (plastomes) have long been recognized as highly conserved in their overall structure, size, gene arrangement and content among land plants. However, recent studies have shown that some lineages present unusual variations in some of these features. Members of the cactus family are one of these lineages, with distinct plastome structures reported across disparate lineages, including gene losses, inversions, boundary movements or loss of the canonical inverted repeat (IR) region. However, only a small fraction of cactus diversity has been analysed so far. METHODS: Here, we investigated plastome features of the tribe Opuntieae, the remarkable prickly pear cacti, which represent one of the most diverse and important lineages of Cactaceae. We assembled de novo the plastome of 43 species, representing a comprehensive sampling of the tribe, including all seven genera, and analysed their evolution in a phylogenetic comparative framework. Phylogenomic analyses with different datasets (full plastome sequences and genes only) were performed, followed by congruence analyses to assess signals underlying contentious nodes. KEY RESULTS: Plastomes varied considerably in length, from 121 to 162 kbp, with striking differences in the content and size of the IR region (contraction and expansion events), including a lack of the canonical IR in some lineages and the pseudogenization or loss of some genes. Overall, nine different types of plastomes were reported, deviating in the presence of the IR region or the genes contained in the IR. Overall, plastome sequences resolved phylogenetic relationships within major clades of Opuntieae with high bootstrap values but presented some contentious nodes depending on the dataset analysed (e.g. whole plastome vs. genes only). Congruence analyses revealed that most plastidial regions lack phylogenetic resolution, while few markers are supporting the most likely topology. Likewise, alternative topologies are driven by a handful of plastome markers, suggesting recalcitrant nodes in the phylogeny. CONCLUSIONS: Our study reveals a dynamic nature of plastome evolution across closely related lineages, shedding light on peculiar features of plastomes. Variation of plastome types across Opuntieae is remarkable in size, structure and content and can be important for the recognition of species in some major clades. Unravelling connections between the causes of plastome variation and the consequences for species biology, physiology, ecology, diversification and adaptation is a promising and ambitious endeavour in cactus research. Although plastome data resolved major phylogenetic relationships, the generation of nuclear genomic data is necessary to confront these hypotheses and assess the recalcitrant nodes further.

Asunto(s)

RESUMEN

The objective of the study was to evaluate the incidence of COVID-19 after complete vaccination in people with multiple sclerosis (PwMS) included in the Argentinean MS and NMOSD registry (RelevarEM, NCT03375177). METHODS: cohort study conducted between May 2021 and December 2021. The primary outcome was the appearance of infection during the follow-up time (at least three months after complete vaccination (second dose)). Data was collected through the contact between the treating physician and the patient. Specific information was requested (date, symptoms, need for hospitalization, ventilatory assistance, treatment, and evolution). The contact was made every 30 days during the period of 3 months after the full dose vaccination. A positive COVID-19 case was defined according to the definition established by the Ministry of Health in Argentina. Cumulative incidence was reported by Kaplan Meier survival curves as well as incidence density. RESULTS: A total of 576 PwMS were included, mean age 45.2 ± 13 years, 432 (75%) RRMS, 403 (70%) were female. The mean and median time of follow-up after the second dose was 91 ± 17 and 94 ± 21 days respectively. Most frequent first and second dose received was Astra-Zeneca vaccine, followed by Sputnik V vaccine. During follow-up a total of twenty COVID-19 cases were observed for a total exposure time of 39,557 days. The overall cumulative incidence for the observed period was 3.4% (SE 0.4%) with an overall incidence density of 5 × 10.000 patients/day (95%CI 0.7-12). We observed more cases in woman than men with an incidence density of 6 × 10.000 patients/day (95%CI 0.9-9) vs. 3 × 10.000 patients/day (95%CI 0.2-6) respectively, but not significantly different (IRR 1.7 95% CI 0.56-7.37 p = 0.15). CONCLUSION: we found an incidence density of breakthrough COVID-19 infection of 5 × 10.000 patients/day (95%CI 0.7-12) after vaccination in Argentina.

Asunto(s)

RESUMEN

The objectives of the present study were to describe the frequency of aggressive multiple sclerosis (aMS) as well as to compare clinical and radiological characteristics in aMS and non-aMS patients included in RelevarEM (NCT03375177). METHODS: The eligible study population and cohort selection included adult-onset patients (≥18 years) with definite MS. AMS were defined as those reaching confirmed EDSS ≥ 6 within 5 years from symptom onset. Confirmation was achieved when a subsequent EDSS ≥ 6 was recorded at least six months later but within 5 years of the first clinical presentation. AMS and non-aMS were compared using the χ2 test for categorical and the Mann-Whitney for continuous variables at MS onset and multivariable analysis was performed using forward stepwise logistic regression with baseline characteristics at disease onset. RESULTS: A total of 2158 patients with MS were included: 74 aMS and 2084 non-aMS. The prevalence of aMS in our cohort was 3.4% (95%CI 2.7-4.2). AMS were more likely to be male (p = 0.003), older at MS onset (p < 0.001), have primary progressive MS (PPMS) phenotype (p = 0.03), multifocal presentation (p < 0.001), and spinal cord as well as infratentorial lesions at MRI during disease onset (p = 0.004 and p = 0.002, respectively). CONCLUSION: 3.4% of our patient population could be considered aMS. Men, patients older at symptom onset, multifocal presentation, PPMS phenotype, and spinal cord as well as brainstem lesions on MRI at clinical presentation all had higher odds of having aMS.

Asunto(s)

RESUMEN

BACKGROUND: Like MS prevalence, oligoclonal bands (OCB) frequency seems to follow a latitudinal gradient. Argentina is extensive, latitude-wise, and previous studies have not found an MS prevalence latitudinal gradient. Our aim is to describe OCB prevalence in MS, clinically isolated syndrome (CIS) and radiologically isolated syndrome (RIS) patients included in the Argentinean MS and NMOSD registry (RelevarEM) and to investigate if it follows a latitudinal gradient. METHODS: For each province, an average latitude was calculated, and OCB frequency was investigated. Multivariate logistical regression analysis and linear correlation were performed. Statistical analysis was repeated after excluding patients from centers using isoelectric focusing (IEF) in less than 95% of patients (CwIEF<95). RESULTS: We included 2866 patients. OCB where positive in 73.9% of patients. No association or correlation were found between OCB and latitude of residence, even after excluding patients from (CwIEF<95). CONCLUSION: OCB positivity does not follow a latitudinal gradient in Argentina. Also, OCB positivity is lower than described in other world regions.

Asunto(s)

RESUMEN

Chloroplast genomes (plastomes) are frequently treated as highly conserved among land plants. However, many lineages of vascular plants have experienced extensive structural rearrangements, including inversions and modifications to the size and content of genes. Cacti are one of these lineages, containing the smallest plastome known for an obligately photosynthetic angiosperm, including the loss of one copy of the inverted repeat (∼25 kb) and the ndh gene suite, but only a few cacti from the subfamily Cactoideae have been sufficiently characterized. Here, we investigated the variation of plastome sequences across the second-major lineage of the Cactaceae, the subfamily Opuntioideae, to address (1) how variable is the content and arrangement of chloroplast genome sequences across the subfamily, and (2) how phylogenetically informative are the plastome sequences for resolving major relationships among the clades of Opuntioideae. Our de novo assembly of the Opuntia quimilo plastome recovered an organelle of 150,347 bp in length with both copies of the inverted repeat and the presence of all the ndh gene suite. An expansion of the large single copy unit and a reduction of the small single copy unit was observed, including translocations and inversion of genes, as well as the putative pseudogenization of some loci. Comparative analyses among all clades within Opuntioideae suggested that plastome structure and content vary across taxa of this subfamily, with putative independent losses of the ndh gene suite and pseudogenization of genes across disparate lineages, further demonstrating the dynamic nature of plastomes in Cactaceae. Our plastome dataset was robust in resolving three tribes with high support within Opuntioideae: Cylindropuntieae, Tephrocacteae and Opuntieae. However, conflicting topologies were recovered among major clades when exploring different assemblies of markers. A plastome-wide survey for highly informative phylogenetic markers revealed previously unused regions for future use in Sanger-based studies, presenting a valuable dataset with primers designed for continued evolutionary studies across Cactaceae. These results bring new insights into the evolution of plastomes in cacti, suggesting that further analyses should be carried out to address how ecological drivers, physiological constraints and morphological traits of cacti may be related with the common rearrangements in plastomes that have been reported across the family.

RESUMEN

Cactaceae comprise a diverse and iconic group of flowering plants which are almost exclusively indigenous to the New World. The wide variety of growth forms found amongst the cacti have led to the trafficking of many species throughout the world as ornamentals. Despite the evolution and physiological properties of these plants having been extensively studied, little research has focused on cactus-associated viral communities. While only single-stranded RNA viruses had ever been reported in cacti, here we report the discovery of cactus-infecting single-stranded DNA viruses. These viruses all apparently belong to a single divergent species of the family Geminiviridae and have been tentatively named Opuntia virus 1 (OpV1). A total of 79 apparently complete OpV1 genomes were recovered from 31 different cactus plants (belonging to 20 different cactus species from both the Cactoideae and Opuntioideae clades) and from nine cactus-feeding cochineal insects (Dactylopius sp.) sampled in the USA and Mexico. These 79 OpV1 genomes all share > 78.4% nucleotide identity with one another and < 64.9% identity with previously characterized geminiviruses. Collectively, the OpV1 genomes display evidence of frequent recombination, with some genomes displaying up to five recombinant regions. In one case, recombinant regions span ~40% of the genome. We demonstrate that an infectious clone of an OpV1 genome can replicate in Nicotiana benthamiana and Opuntia microdasys. In addition to expanding the inventory of viruses that are known to infect cacti, the OpV1 group is so distantly related to other known geminiviruses that it likely represents a new geminivirus genus. It remains to be determined whether, like its cactus hosts, its geographical distribution spans the globe.

Asunto(s)