Users opinions about Learning Object Recommendations: a case study

[EN]—The enormous growth of learning objects on the internet and the availability of preferences of usage by the community of users in the existing learning object repositories have opened the possibility of testing the efficiency of different techniques on recommending learning materials to the users of these communities. In this work, we focus on some particular parameters at the recommendation phase (different similarity algorithms), evaluating the new recommendations not only via offline analysis but also taking into account users feedback. It has been performed a online analysis over a small group of users. The recommendations were presented to these users along with a small inquiry form about each recommendation. Through this study we tried to find out which algorithm performs better from the online analysis and if it is possible to notice a similarity between the results obtained from the offline and online analysis

Feline immunodeficiency virus Vif N-Terminal residues selectively counteract feline APOBEC3s

Feline immunodeficiency virus (FIV) Vif protein counteracts feline APOBEC3s (FcaA3s) restriction factors by inducing their proteasomal degradation. The functional domains in FIV Vif for interaction with FcaA3s are poorly understood. Here, we have identified several motifs in FIV Vif that are important for selective degradation of different FcaA3s. Cats (Felis catus) express three types of A3s: single-domain A3Z2, single-domain A3Z3, and double-domain A3Z2Z3. We proposed that FIV Vif would selectively interact with the Z2 and the Z3 A3s. Indeed, we identified two N-terminal Vif motifs (12LF13 and 18GG19) that specifically interacted with the FcaA3Z2 protein but not with A3Z3. In contrast, the exclusive degradation of FcaA3Z3 was regulated by a region of three residues (M24, L25, and I27). Only a FIV Vif carrying a combination of mutations from both interaction sites lost the capacity to degrade and counteract FcaA3Z2Z3. However, alterations in the specific A3s interaction sites did not affect the cellular localization of the FIV Vif protein and binding to feline A3s. Pulldown experiments demonstrated that the A3 binding region localized to FIV Vif residues 50 to 80, outside the specific A3 interaction domain. Finally, we found that the Vif sites specific to individual A3s are conserved in several FIV lineages of domestic cat and nondomestic cats, while being absent in the FIV Vif of pumas. Our data support a complex model of multiple Vif-A3 interactions in which the specific region for selective A3 counteraction is discrete from a general A3 binding domain

Could phylogenetic analysis be used for feline Leukemia Virus (FeLV) classification?

The surface envelope (SU) protein determines the cell tropism and consequently the pathogenesis of the feline leukemia virus (FeLV) in felids. Recombination of exogenous FeLV (exFeLV) with endogenous retroviruses (enFeLV) allows the emergence of more pathogenic variants. Currently, phenotypic testing through interference assays is the only method to distinguish among subgroups—namely, FeLV-A, -B, -C, -E, and -T. This study proposes a new method for FeLV classification based on molecular analysis of the SU gene. A total of 404 publicly available SU sequences were used to reconstruct a maximum likelihood tree. However, only 63 of these sequences had available information about phenotypic tests or subgroup assignments. Two major clusters were observed: (a) clade FeLV-A, which includes FeLV-A, FeLV-C, FeLV-E, and FeLV-T sequences, and (b) clade enFeLV, which includes FeLV-B and enFeLV strains. We found that FeLV-B, FeLV-C, FeLV-E, and FeLV-T SU sequences share similarities to FeLV-A viruses and most likely arose independently through mutation or recombination from this strain. FeLV-B and FeLV-C arose from recombination between FeLV-A and enFeLV viruses, whereas FeLV-T is a monophyletic subgroup that has probably originated from FeLV-A through combined events of deletions and insertions. Unfortunately, this study could not identify polymorphisms that are specifically linked to the FeLV-E subgroup. We propose that phylogenetic and recombination analysis together can explain the current phenotypic classification of FeLV viruses

Real-time genomic surveillance during the 2021 re-emergence of the yellow fever virus in Rio Grande do Sul state, Brazil

The 2021 re-emergence of yellow fever in non-human primates in the state of Rio Grande do Sul (RS), southernmost Brazil, resulted in the death of many howler monkeys (genus Alouatta) and led the state to declare a Public Health Emergency of State Importance, despite no human cases reported. In this study, near-complete genomes of yellow fever virus (YFV) recovered from the outbreak were sequenced and examined aiming at a better understanding of the phylogenetic relationships and the spatio-temporal dynamics of the virus distribution. Our results suggest that the most likely sequence of events involved the reintroduction of YFV from the state of São Paulo to RS through the states of Paraná and Santa Catarina, by the end of 2020. These findings reinforce the role of genomic surveillance in determining the pathways of distribution of the virus and in providing references for the implementation of preventive measures for populations in high risk areas

Draft Genome Sequence of <i>Bacillus thuringiensis</i> Strain m401, Isolated from Honey in Argentina

We report here the 6,092,003-bp draft genome sequence of Bacillus thuringiensis strain m401, a tetracycline-resistant isolate recovered from honey. The isolate contained three plasmids of 8,307 bp, 9,934 bp, and 69,561 bp and a tetracycline resistance gene with high homology to tet45 in a contig of 236,180 bp.Centro de Investigaciones en Fitopatologí

Yellow fever virus maintained by Sabethes mosquitoes during the dry season in Cerrado, a Semiarid Region of Brazil, in 2021

In recent decades, waves of yellow fever virus (YFV) from the Amazon Rainforest have spread and caused outbreaks in other regions of Brazil, including the Cerrado, a savannah-like biome through which YFV usually moves before arriving at the Atlantic Forest. To identify the vectors involved in the maintenance of the virus in semiarid environments, an entomological survey was conducted after confirmation of yellow fever (YF) epizootics at the peak of the dry season in the Cerrado areas of the state of Minas Gerais. In total, 917 mosquitoes from 13 taxa were collected and tested for the presence of YFV. Interestingly, mosquitoes of the Sabethes genus represented 95% of the diurnal captured specimens, displaying a peak of biting activity never previously recorded, between 4:30 and 5:30 p.m. Molecular analysis identified three YFV-positive pools, two from Sabethes chloropterus—from which near-complete genomes were generated—and one from Sa. albiprivus, whose low viral load prevented sequencing. Sa. chloropterus was considered the primary vector due to the high number of copies of YFV RNA and the high relative abundance detected. Its bionomic characteristics allow its survival in dry places and dry time periods. For the first time in Brazil, Sa. albiprivus was found to be naturally infected with YFV and may have played a role as a secondary vector. Despite its high relative abundance, fewer copies of viral RNA were found, as well as a lower Minimum Infection Rate (MIR). Genomic and phylogeographic analysis showed that the virus clustered in the sub-lineage YFVPA-MG, which circulated in Pará in 2017 and then spread into other regions of the country. The results reported here contribute to the understanding of the epidemiology and mechanisms of YFV dispersion and maintenance, especially in adverse weather conditions. The intense viral circulation, even outside the seasonal period, increases the importance of surveillance and YFV vaccination to protect human populations in affected areas

Comparison between DNA detection in trigeminal nerve ganglia and serology to detect cattle infected with bovine herpesviruses types 1 and 5

Bovine herpesviruses (BoHVs) types 1 (BoHV-1) and 5 (BoHV-5) are alphaherpesviruses of major importance to the bovine production chain. Such viruses are capable of establishing latent infections in neuronal tissues. Infected animals tend to develop a serological response to infection; however, such response—usually investigated by antibody assays in serum—may eventually not be detected in laboratory assays. Nevertheless, serological tests such as virus neutralization (VN) and various enzyme-linked immunosorbent assays (ELISAs) are widely employed to check individual or herd status of BoHV infections. The correlation between detection of antibodies and the presence of viral nucleic acids as indicatives of infection in infected cattle has not been deeply examined. In order to investigate such correlation, 248 bovine serum samples were tested by VN to BoHV-1 and BoHV-5, as well as in a widely employed (though not type-differential) gB ELISA (IDEXX IBR gB X2 Ab Test) in search for antibodies to BoHVs. Immediately after blood withdrawal, cattle were slaughtered and trigeminal ganglia (TG) excised for DNA extraction and viral nucleic acid detection (NAD) by nested PCR. Neutralizing antibodies to BoHV-1 and/or BoHV-5 were detected in 44.8% (111/248) of sera, whereas the gB ELISA detected antibodies in 51.2% (127/248) of the samples. However, genomes of either BoHV-1, BoHV-5, or both, were detected in TGs of 85.9% (213/248) of the animals. These findings reveal that the assays designed to detect antibodies to BoHV-1 and/or BoHV-5 employed here may fail to detect a significant number of latently infected animals (in this study, 35.7%). From such data, it is clear that antibody assays are poorly correlated with detection of viral genomes in BoHV-1 and BoHV-5-infected animals

Serological evidence of orthopoxvirus infection in neotropical primates in Brazil

The genus Orthopoxvirus (OPXV) of the family Poxviridae comprises several viruses that are capable of infecting a wide range of hosts. One of the most widespread OPXVs is the Vaccinia virus (VACV), which circulates in zoonotic cycles in South America, especially in Brazil, infecting domestic and wild animals and humans and causing economic losses as well as impacting public health. Despite this, little is known about the presence and/or exposure of neotropical primates to orthopoxviruses in the country. In this study, we report the results of a search for evidence of OPVX infections in neotropical free-living primates in the state of Minas Gerais, southeast Brazil. The sera or liver tissues of 63 neotropical primates were examined through plaque reduction neutralization tests (PRNT) and real-time PCR. OPXV-specific neutralizing antibodies were detected in two sera (4.5%) from Callithrix penicillata, showing 55% and 85% reduction in plaque counts, evidencing their previous exposure to the virus. Both individuals were collected in urban areas. All real-time PCR assays were negative. This is the first time that evidence of OPXV exposure has been detected in C. penicillata, a species that usually lives at the interface between cities and forests, increasing risks of zoonotic transmissions through spillover/spillback events. In this way, studies on the circulation of OPXV in neotropical free-living primates are necessary, especially now, with the monkeypox virus being detected in new regions of the planet