The SARS-CoV-2 pandemic has affected also the school environment. Prolonged closures and the weakness of available data prevent a definitive answer to the question of school transmission. We report ...our experience of responding to COVID-19 cases in the school setting, presenting a case study of the management of an outbreak in a large school.
The LHA/ASL Roma 1 has organized the School Units with a structure firmly rooted in the territory. At the local level, the District Unit mainly manages the relationship with schools, while the Hygiene and Public Health Service of the Prevention Department holds a coordinating and facilitating role. The HPHS carries out contact tracing activities facilitated by the schools, through the figure of the COVID-19 Contact Person, who is specifically trained to manage the preliminary stages of the reports.
Following several reports of COVID-19 suspect cases from two schools and, after a complex phase of contact tracing, it was possible to identify the major transmission chains. Furthermore, we performed a population-based screening on the entire school. Beyond the known transmission chains, for which quarantine was already in place, only five additional cases emerged, all asymptomatic, out of 1,231 swabs tested with RT-PCR.
Our experience confirms that an active interaction between the school and the School Unit made it possible to quickly control a potentially dangerous outbreak. The large-scale screening test demonstrated the substantial absence of collateral transmission chains. Effective contact tracing allowed to set forth a successful response. Our model of intervention can be used to support public health protocols regarding school outbreaks.
Diffraction data and quasicrystallography provide average quasiperiodic structures for real quasicrystals. In the present paper it is reported a detailed analysis of one of these quasiperiodic ...structures, with the emphasis on complementarity of Mackay- and Bergman-like polyhedra as well as on chemical order aspects.
Proteoforms expand genomic diversity and direct developmental processes. While high-resolution mass spectrometry has accelerated characterization of proteoforms, molecular techniques working to bind ...and disrupt the function of specific proteoforms have lagged behind. In this study, we worked to develop intrabodies capable of binding specific proteoforms. We employed a synthetic camelid nanobody library expressed in yeast to identify nanobody binders of different SARS-CoV-2 receptor binding domain (RBD) proteoforms. Importantly, employment of the positive and negative selection mechanisms inherent to the synthetic system allowed for amplification of nanobody-expressing yeast that bind to the original (Wuhan strain RBD) but not the E484 K (Beta variant) mutation. Nanobodies raised against specific RBD proteoforms were validated by yeast-2-hybrid analysis and sequence comparisons. These results provide a framework for development of nanobodies and intrabodies that target proteoforms.
Phytic acid (myo-inositol-1, 2, 3, 4, 5, 6-hexakisphosphate or Ins P6) typically represents approximately 75% to 80% of maize (Zea mays) seed total P. Here we describe the origin, inheritance, and ...seed phenotype of two non-lethal maize low phytic acid mutants, lpa1-1 and lpa2-1. The loci map to two sites on chromosome 1S. Seed phytic acid P is reduced in these mutants by 50% to 66% but seed total P is unaltered. The decrease in phytic acid P in mature lpa1-1 seeds is accompanied by a corresponding increase in inorganic phosphate (Pi). In mature lpa2-1 seed it is accompanied by increases in Pi and at least three other myo-inositol (Ins) phosphates (and/or their respective enantiomers): D-Ins(1,2,4,5,6) P5; D-Ins (1,4,5,6) P4; and D-Ins(1,2,6) P3. In both cases the sum of seed Pi and Ins phosphates (including phytic acid) is constant and similar to that observed in normal seeds. In both mutants P chemistry appears to be perturbed throughout seed development. Homozygosity for either mutant results in a seed dry weight loss, ranging from 4% to 23%. These results indicate that phytic acid metabolism during seed development is not solely responsible for P homeostasis and indicate that the phytic acid concentration typical of a normal maize seed is not essential to seed function.
The Leishmania (Viannia) braziliensis complex is responsible for most cases of New World tegumentary leishmaniasis. This complex includes two closely related species but with different geographic ...distribution and disease phenotypes, L. (V.) peruviana and L. (V.) braziliensis. However, the genetic basis of these differences is not well understood and the status of L. (V.) peruviana as distinct species has been questioned by some. Here we sequenced the genomes of two L. (V.) peruviana isolates (LEM1537 and PAB-4377) using Illumina high throughput sequencing and performed comparative analyses against the L. (V.) braziliensis M2904 reference genome. Comparisons were focused on the detection of Single Nucleotide Polymorphisms (SNPs), insertions and deletions (INDELs), aneuploidy and gene copy number variations.
We found 94,070 variants shared by both L. (V.) peruviana isolates (144,079 in PAB-4377 and 136,946 in LEM1537) against the L. (V.) braziliensis M2904 reference genome while only 26,853 variants separated both L. (V.) peruviana genomes. Analysis in coding sequences detected 26,750 SNPs and 1,513 indels shared by both L. (V.) peruviana isolates against L. (V.) braziliensis M2904 and revealed two L. (V.) braziliensis pseudogenes that are likely to have coding potential in L. (V.) peruviana. Chromosomal read density and allele frequency profiling showed a heterogeneous pattern of aneuploidy with an overall disomic tendency in both L. (V.) peruviana isolates, in contrast with a trisomic pattern in the L. (V.) braziliensis M2904 reference. Read depth analysis allowed us to detect more than 368 gene expansions and 14 expanded gene arrays in L. (V.) peruviana, and the likely absence of expanded amastin gene arrays.
The greater numbers of interspecific SNP/indel differences between L. (V.) peruviana and L. (V.) braziliensis and the presence of different gene and chromosome copy number variations support the classification of both organisms as closely related but distinct species. The extensive nucleotide polymorphisms and differences in gene and chromosome copy numbers in L. (V.) peruviana suggests the possibility that these may contribute to some of the unique features of its biology, including a lower pathology and lack of mucosal development.
•A new nanostructured TiO2 film deposited on a stainless steel mesh was prepared.•The new supported photocatalyst was successfully reused several times.•Identified by-products revealed minor ...differences between photocatalytic processes.•Toxicity tests showed that few of them are useful for investigating CECs degradation.
A new supported catalyst composed of a nanostructured TiO2 film deposited on a stainless steel mesh (nanoTiO2-SS) using the Metal Organic Chemical Vapour Deposition (MOCVD) technique was evaluated for the photocatalytic degradation of a mixture of contaminants of emerging concern. Results showed that under the oxidative conditions tested, the nanoTiO2-SS catalyst demonstrated an efficiency in degrading the target contaminants higher than that observed under direct photolysis and photocatalysis using the conventional TiO2 Degussa P25 catalyst at the same amount of TiO2 participating to the photocatalysis. Specifically, the rate of removal of warfarin and trimethoprim obtained with the new catalyst was found twice the one observed by using TiO2 Degussa P25 and approximately 1.6 times faster for metoprolol, carbamazepine and gemfibrozil. An evaluation of the electrical energy per order magnitude of removal (EE/O) confirmed the enhanced performance of the new catalyst (24.3–31.8kWhm−3 rather than 32.8–39.3kWhm−3 for conventional TiO2) and that the performance is compound-dependent. Toxicity testing revealed that some assays are suitable for the investigation of bioactivity of treated waters containing contaminants of emerging concern at μgL−1 level. Specifically, the AMES Fluctuation Test, Fish Embryo Acute Toxicity Test and Green alga Selenastrum capricornutum test provided valuable results for an environmental impact assessment. On the other hand, the Daphnia magna and Vibrio fischeri acute toxicity tests were not sensitive enough to detect bioactivity in the samples analysed without prior pre-concentration.
SARS-CoV-2 cellular infection is mediated by the heavily glycosylated spike protein. Recombinant versions of the spike protein and the receptor-binding domain (RBD) are necessary for seropositivity ...assays and can potentially serve as vaccines against viral infection. RBD plays key roles in the spike protein’s structure and function, and thus, comprehensive characterization of recombinant RBD is critically important for biopharmaceutical applications. Liquid chromatography coupled to mass spectrometry has been widely used to characterize post-translational modifications in proteins, including glycosylation. Most studies of RBDs were performed at the proteolytic peptide (bottom-up proteomics) or released glycan level because of the technical challenges in resolving highly heterogeneous glycans at the intact protein level. Herein, we evaluated several online separation techniques: (1) C2 reverse-phase liquid chromatography (RPLC), (2) capillary zone electrophoresis (CZE), and (3) acrylamide-based monolithic hydrophilic interaction chromatography (HILIC) to separate intact recombinant RBDs with varying combinations of glycosylations (glycoforms) for top-down mass spectrometry (MS). Within the conditions we explored, the HILIC method was superior to RPLC and CZE at separating RBD glycoforms, which differ significantly in neutral glycan groups. In addition, our top-down analysis readily captured unexpected modifications (e.g., cysteinylation and N-terminal sequence variation) and low abundance, heavily glycosylated proteoforms that may be missed by using glycopeptide data alone. The HILIC top-down MS platform holds great potential in resolving heterogeneous glycoproteins for facile comparison of biosimilars in quality control applications.
Embryonic stem cells (ESCs) possess a distinct chromatin conformation maintained by specialized chromatin proteins. To identify chromatin regulators in ESCs, we developed a simple biochemical assay ...named D-CAP (differential chromatin-associated proteins), using brief micrococcal nuclease digestion of chromatin, followed by liquid chromatography tandem mass spectrometry (LC-MS/MS). Using D-CAP, we identified several differentially chromatin-associated proteins between undifferentiated and differentiated ESCs, including the chromatin remodeling protein SMARCD1. SMARCD1 depletion in ESCs led to altered chromatin and enhanced endodermal differentiation. Gene expression and chromatin immunoprecipitation sequencing (ChIP-seq) analyses suggested that SMARCD1 is both an activator and a repressor and is enriched at developmental regulators and that its chromatin binding coincides with H3K27me3. SMARCD1 knockdown caused H3K27me3 redistribution and increased H3K4me3 around the transcription start site (TSS). One of the identified SMARCD1 targets was Klf4. In SMARCD1-knockdown clones, KLF4, as well as H3K4me3 at the Klf4 locus, remained high and H3K27me3 was abolished. These results propose a role for SMARCD1 in restricting pluripotency and activating lineage pathways by regulating H3K27 methylation.
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•D-CAP identifies differentially bound chromatin proteins between different cell types•SMARCD1, identified by D-CAP, regulates ectodermal differentiation of ESCs•SMARCD1 is associated with bivalent genes and regulates H3K4me3/H3K27me3 distribution•SMARCD1 binds and regulates Klf4 directly and indirectly
Alajem et al. develop an assay that indicates differential association of SMARCD1 with chromatin in embryonic stem cells (ESCs) and early-differentiating cells. SMARCD1 is associated with bivalent genes in ESCs, regulates H3K4me3/H3K27me3 distribution, and binds and regulates the pluripotency factor Klf4.
Outdoor malaria transmission hinders malaria elimination efforts in the Amazon region and novel vector control tools are needed. Ivermectin mass drug administration (MDA) to humans kills wild ...Anopheles, targets outdoor-feeding vectors, and can suppress malaria parasite transmission. Laboratory investigations were performed to determine ivermectin susceptibility, sporontocidal effect and inhibition of time to re-feed for the primary Amazonian malaria vector, Anopheles darlingi.
To assess ivermectin susceptibility, various concentrations of ivermectin were mixed in human blood and fed to An. darlingi. Mosquito survival was monitored daily for 7 days and a non-linear mixed effects model with Probit analysis was used to calculate lethal concentrations of ivermectin that killed 50% (LC
), 25% (LC
) and 5% (LC
) of mosquitoes. To examine ivermectin sporonticidal effect, Plasmodium vivax blood samples were collected from malaria patients and offered to mosquitoes without or with ivermectin at the LC
, LC
or LC
. To assess ivermectin inhibition of mosquito time to re-feed, concentrations of ivermectin predicted to occur after a single oral dose of 200 μg/kg ivermectin were fed to An. darlingi. Every day for 12 days thereafter, individual mosquitoes were given the opportunity to re-feed on a volunteer. Any mosquitoes that re-blood fed or died were removed from the study.
Ivermectin significantly reduced An. darlingi survivorship: 7-day-LC
= 43.2 ng/ml 37.5, 48.6, -LC
= 27.8 ng/ml 20.4, 32.9 and -LC
= 14.8 ng/ml 7.9, 20.2. Ivermectin compound was sporontocidal to P. vivax in An. darlingi at the LC
and LC
concentrations reducing prevalence by 22.6 and 17.1%, respectively, but not at the LC
. Oocyst intensity was not altered at any concentration. Ivermectin significantly delayed time to re-feed at the 4-h (48.7 ng/ml) and 12-h (26.9 ng/ml) concentrations but not 36-h (10.6 ng/ml) or 60-h (6.3 ng/ml).
Ivermectin is lethal to An. darlingi, modestly inhibits sporogony of P. vivax, and delays time to re-feed at concentrations found in humans up to 12 h post drug ingestion. The LC
value suggests that a higher than standard dose (400-μg/kg) is necessary to target An. darlingi. These results suggest that ivermectin MDA has potential in the Amazon region to aid malaria elimination efforts.
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