Calculation Method to Determine the Group Composition of Vacuum Distillate with High Content of Saturated Hydrocarbons

Calculation method to determine the group composition of the heavy fraction of vacuum distillate with high content of saturated hydrocarbons, obtained by vacuum distillation of the residue from the West Siberian oil with subsequent hydrotreating, are given in this research. The method is built on the basis of calculation the physico-chemical characteristics and the group composition of vacuum distillate according to the fractional composition and density considering with high content of saturated hydrocarbons in the fraction. Calculation method allows to determine the content of paraffinic, naphthenic, aromatic hydrocarbons and the resins in vacuum distillate with high accuracy and can be used in refineries for rapid determination of the group composition of vacuum distillate

Listeria monocytogenes meningoencephalitis against the background of the new coronavirus infection: a clinical case

Background: Among the bacteria that affect the central nervous system, Listeria monocytogenes (facultative intracellular bacterium) is one of the most lethal to humans and animals. Listeriosis affects domestic and farm animals (pigs, small and large cattle, horses, rabbits, less often cats and dogs), as well as domestic and ornamental birds (geese, chickens, ducks, turkeys, pigeons, parrots and canaries). L. monocytogenes can be detected in fish and seafood (shrimp). The source of L. monocytogenes infection are animals in which the disease may manifest itself or occur in erased and asymptomatic forms followed by the transition to a long-term carriage. This pathogen is found throughout the world in foodstuffs, and most cases of infection occur through the ingestion of contaminated food. Particularly susceptible to the disease are embryos, newborns, the elderly and individuals with immunodeficiencies and chronic diseases. L. monocytogenes can cause intracranial hemorrhage, meningitis, meningoencephalitis, and rhombencephalitis. Clinical case description: This paper presents our own clinical observation of the development of severe listeriosis meningoencephalitis in a 47 year-old patient against the background of the new coronavirus infection (COVID-19). We describe the details of the clinical presentation, the treatment and the favorable outcome in our patient. Conclusion: Invasive listeriosis is a rare disease. The knowledge about the clinical manifestations of this disease is needed not only for epidemiologists and infectious disease specialists, but also for physicians of other specialties. Untimely diagnosis and inadequate antibacterial therapy are dangerous leading to severe somatic and neurological complications with a lethal outcome or disability both in children and adult persons

Antibodies to S2 domain of SARS-CoV-2 spike protein in Moderna mRNA vaccinated subjects sustain antibody-dependent NK cell-mediated cell cytotoxicity against Omicron BA.1

Vaccination with the primary two-dose series of SARS-CoV-2 mRNA protects against infection with the ancestral strain, and limits the presentation of severe disease after re-infection by multiple variants of concern (VOC), including Omicron, despite the lack of a strong neutralizing response to these variants. We compared antibody responses in serum samples collected from mRNA-1273 (Moderna) vaccinated subjects to identify mechanisms of immune escape and cross-protection. Using pseudovirus constructs containing domain-specific amino acid changes representative of Omicron BA.1, combined with domain competition and RBD-antibody depletion, we showed that RBD antibodies were primarily responsible for virus neutralization and variant escape. Antibodies to NTD played a less significant role in antibody neutralization but acted along with RBD to enhance neutralization. S2 of Omicron BA.1 had no impact on neutralization escape, suggesting it is a less critical domain for antibody neutralization; however, it was as capable as S1 at eliciting IgG3 responses and NK-cell mediated, antibody-dependent cell cytotoxicity (ADCC). Antibody neutralization and ADCC activities to RBD, NTD, and S1 were all prone to BA.1 escape. In contrast, ADCC activities to S2 resisted BA.1 escape. In conclusion, S2 antibodies showed potent ADCC function and resisted Omicron BA.1 escape, suggesting that S2 contributes to cross-protection against Omicron BA.1. In line with its conserved nature, S2 may hold promise as a vaccine target against future variants of SARS-CoV-2

Calculation Method to Determine the Group Composition of Vacuum Distillate with High Content of Saturated Hydrocarbons

Calculation method to determine the group composition of the heavy fraction of vacuum distillate with high content of saturated hydrocarbons, obtained by vacuum distillation of the residue from the West Siberian oil with subsequent hydrotreating, are given in this research. The method is built on the basis of calculation the physico-chemical characteristics and the group composition of vacuum distillate according to the fractional composition and density considering with high content of saturated hydrocarbons in the fraction. Calculation method allows to determine the content of paraffinic, naphthenic, aromatic hydrocarbons and the resins in vacuum distillate with high accuracy and can be used in refineries for rapid determination of the group composition of vacuum distillate

Tetramer organizing polyproline-rich peptides identified by mass spectrometry after release of the peptides from Hupresin-purified butyrylcholinesterase tetramers isolated from milk of domestic pig (Sus scrofa)

Milk of the domestic pig has 10 times more butyrylcholinesterase (BChE) per mL than porcine serum. We purified BChE from porcine milk by affinity chromatography on Hupresin-Sepharose. The pure porcine BChE (PoBChE) was a tetramer with a molecular weight of 340,000, similar to that of human BChE tetramers. The C-terminal 40 residues of PoBChE constitute the tetramerization domain. The glue that holds the 4 BChE subunits together is a polyproline-rich peptide. Mass spectrometry analysis of trypsin-digested PoBChE identified a variety of polyproline-rich peptides originating from 12 different proteins. The donor proteins exist in the nucleus or cytoplasm of cells and contribute their polyproline-rich peptides after a cell is degraded. The secreted PoBChE scavenges the polyproline-rich peptides and incorporates one polyproline peptide per PoBChE tetramer, where the polyproline peptide is bound noncovalently but very tightly with an estimated dissociation constant of 10–12 M. The most abundant polyproline-rich peptides were derived from acrosin, homeobox protein HoxB4, lysine-specific demethylase 6B, proline-rich protein 12, and proline-rich membrane anchor 1 (PRiMA). The research article associated with the data in this report can be found in Saxena et al. (2018). The Data in Brief report lists all the polyproline-rich peptides identified in PoBChE tetramers

Assessment of a Sensitive qPCR Assay Targeting a Multiple-Copy Gene to Detect Orientia tsutsugamushi DNA

Scrub typhus is caused by an obligated intracellular organism, Orientia tsutsugamushi (Orientia). The disease was traditionally thought to be limited in the tsutsugamushi triangle. Recently, scrub typhus has been confirmed in areas outside the triangle. Serological diagnosis of scrub typhus relies on indirect immunofluorescence assay (IFA). Molecular assays such as PCR, qPCR, loop-mediated isothermal amplification, and recombinase polymerase amplification are often targeting a single copy gene. These assays are sensitive and specific, yet they are not broadly used in clinical settings possibly due to low circulating Orientia in blood. In this study, we compared qPCR results using a multiple copy (traD) gene with those using a single copy (47 kDa) gene to assess the improvement of sensitivity and limit of detection. Our results demonstrate that the qPCR using the traD gene provides superior sensitivity in 15 Orientia strains. The limit of detection is below single Orientia genome equivalent and the assay retains specificity with excessive DNA from mouse, chiggers and human. The clinical utility was evaluated using confirmed scrub typhus positive and negative samples. The results show 100% sensitivity and specificity in these samples suggesting that the traD gene qPCR may be useful for clinical diagnosis of Orientia infection

Development of Recombinase Polymerase Amplification Assays for Detection of <i>Orientia tsutsugamushi</i> or <i>Rickettsia typhi</i>

<div><p>Sensitive, specific and rapid diagnostic tests for the detection of <i>Orientia tsutsugamushi</i> (<i>O</i>. <i>tsutsugamushi</i>) and <i>Rickettsia typhi</i> (<i>R</i>. <i>typhi</i>), the causative agents of scrub typhus and murine typhus, respectively, are necessary to accurately and promptly diagnose patients and ensure that they receive proper treatment. Recombinase polymerase amplification (RPA) assays using a lateral flow test (RPA-nfo) and real-time fluorescent detection (RPA-exo) were developed targeting the 47-kDa gene of <i>O</i>. <i>tsutsugamushi</i> or 17 kDa gene of <i>R</i>. <i>typhi</i>. The RPA assay was capable of detecting <i>O</i>. <i>tsutsugamushi</i> or <i>R</i>. <i>typhi</i> at levels comparable to that of the quantitative PCR method. Both the RPA-nfo and RPA-exo methods performed similarly with regards to sensitivity when detecting the 17 kDa gene of <i>R</i>. <i>typhi</i>. On the contrary, RPA-exo performed better than RPA-nfo in detecting the 47 kDa gene of <i>O</i>. <i>tsutsugamushi</i>. The clinical performance of the <i>O</i>. <i>tsutsugamushi</i> RPA assay was evaluated using either human patient samples or infected mouse samples. Eight out of ten PCR confirmed positives were determined positive by RPA, and all PCR confirmed negative samples were negative by RPA. Similar results were obtained for <i>R</i>. <i>typhi</i> spiked patient sera. The assays were able to differentiate <i>O. tsutsugamushi</i> and <i>R. typhi</i> from other phylogenetically related bacteria as well as mouse and human DNA. Furthermore, the RPA-nfo reaction was completed in 20 minutes at 37^oC followed by a 10 minute incubation at room temperature for development of an immunochromatographic strip. The RPA-exo reaction was completed in 20 minutes at 39^oC. The implementation of a cross contamination proof cassette to detect the RPA-nfo fluorescent amplicons provided an alternative to regular lateral flow detection strips, which are more prone to cross contamination. The RPA assays provide a highly time-efficient, sensitive and specific alternative to other methods for diagnosing scrub typhus or murine typhus.</p></div

Evaluation of RPA-nfo assay using XCP cassette.

<p>The RPA-nfo assay for both 17 kDa gene of <i>R</i>. <i>typhi</i> and 47 kDa gene of <i>O</i>. <i>tsutsugamushi</i> was performed as described in Materials and Methods. Upon completion of the assay, the reaction tube was transferred to the cassette and the cassette was closed. The appearance of a red line along the T mark indicated the positive detection of FAM labeled probe. Cassette 1 reaction mixture contained no DNA template and complete primer sets for 47 kDa gene and 17 kDa gene with FAM labeled probes. Cassette 2 was the same as cassette 1 with the addition of 350 copies of <i>O</i>. <i>tsutsugamushi</i> DNA. Cassette 3 was the same as cassette 1 with the addition of 350 copies of <i>R</i>. <i>typhi</i> DNA. *Note: As mentioned previously, no C line was expected because there are no DIG-labeled primers in the RPA reactions, as these cassettes were initially designed for the LAMP assay.</p

Representative results of RPA-nfo for the detection of <i>O</i>. <i>tsutsugamushi</i> or <i>R</i>. <i>typhi</i> genomic DNA.

<p>(A), different copy # of pure <i>O</i>. <i>tsutsugamushi</i> Karp strain genomic DNA as determined by qPCR were added in the RPA reaction. At the end of reaction, amplicons were removed and diluted as described in Materials and Methods for lateral flow strip detection of amplicons. Lane N: negative control, 1–4 contained 600, 220, 53 and 10 copies/reaction of <i>O</i>. <i>tsutsugamushi</i> DNA, respectively. (B), different copy # of pure <i>R</i>. <i>typhi</i> Wilmington strain genomic DNA as determined by qPCR were added as described. Lane N: negative control, lanes 1–4 contained 130, 45, 20, and 6 copies/reaction of <i>R</i>. <i>typhi</i> DNA, respectively. Control band, test band and sample application area are indicated by blue, red and green arrow, respectively.</p

Experimental design.

<p>(A), the two TwistAmp kits used for detection of amplicons using a lateral flow strip, a cross contaminated proof (XCP) cassette, or a real-time monitoring of fluorescent signal. (B),a flowchart of the experimental design from evaluation of primers, optimization of assay conditions, determination of detection limit and evaluation of assay performance.</p