Genomic signatures of parasite-driven natural selection in north European Atlantic salmon (Salmo salar)

Abstract Understanding the genomic basis of host-parasite adaptation is important for predicting the long-term viability of species and developing successful management practices. However, in wild populations, identifying specific signatures of parasite-driven selection often presents a challenge, as it is difficult to unravel the molecular signatures of selection driven by different, but correlated, environmental factors. Furthermore, separating parasite-mediated selection from similar signatures due to genetic drift and population history can also be difficult. Populations of Atlantic salmon (Salmo salar L.) from northern Europe have pronounced differences in their reactions to the parasitic flatworm Gyrodactylus salaris Malmberg 1957 and are therefore a good model to search for specific genomic regions underlying inter-population differences in pathogen response. We used a dense Atlantic salmon SNP array, along with extensive sampling of 43 salmon populations representing the two G. salaris response extremes (extreme susceptibility vs resistant), to screen the salmon genome for signatures of directional selection while attempting to separate the parasite effect from other factors. After combining the results from two independent genome scan analyses, 57 candidate genes potentially under positive selection were identified, out of which 50 were functionally annotated. This candidate gene set was shown to be functionally enriched for lymph node development, focal adhesion genes and anti-viral response, which suggests that the regulation of both innate and acquired immunity might be an important mechanism for salmon response to G. salaris. Overall, our results offer insights into the apparently complex genetic basis of pathogen susceptibility in salmon and highlight methodological challenges for separating the effects of various environmental factors.Peer reviewe

Correction of the toxic effect of cyclophosphamide on hemopoiesis in animals with lewis lung carcinoma using low-molecular-weight sodium alginate

The influence of low-molecular-weight sodium alginate, which is administered as an isolated agent and in combination with cyclophosphamide, on the parameters of peripheral blood and bone marrow was studied in mice with Lewis lung carcinoma. It was shown that administration of sodium alginate with a molecular weight of 1–10 and 20–30 kDa to tumor-bearing animals prevents bone marrow failure by activating the process of regeneration of granulocytic hemopoietic stem cells that are damaged by a single injection or repetitive injections of a cytostatic agent, due to stimulation of the clonal activity of granulocytopoiesis precursors. As a result, this treatment prevents the progression of leukopenia

Commencement Program, August (1966)

https://red.mnstate.edu/commencement/1105/thumbnail.jp

New biological model of moderate inhibition of tumor and metastases growth with prolonged leukopenia in mice

A new biological model of moderate inhibition of tumor growth and metastases with prolonged leukopenia on C57BI/6 mice with the Lewis Lung Carcinoma was designed. The model was created by the injection of cyclophosphamide (dose 83.3 mg/kg) on 6th, 12th, 18th days after tumor cells transplantation on animals. Experiment showed that 3-fold cyclophosphamide use leads to growth of primary tumor and metastases inhibition. Tumor growth inhibition was 34 % on 21st day after cyclophosphamide inject. The number of metastases decreased by 4.7 times (p < 0,01). Metastatic area reduced. Metastasis frequency made 100 %. In addition, the course of cyclophosphamide application caused inhibition of granulocytic and lymphoid hematopoiesis. The reducing the number of segmented neutrophils and lymphocytes was showed on the 3rd day after 1, 2 and 3 injections of cyclophosphamide. The model can be used to study the efficacy of drugs in tumor therapy and in correction of such toxic manifestation of chemotherapy as leukopenia

Determination of HIV Tropism in Patients with Antiretroviral Therapy Failure in Arkhangelsk Region

The aim of the study was to determine the tropism of the human immunodeficiency virus in patients with virological failure of antiretroviral therapy (ART) from the Arkhangelsk Region based on the analysis of the env gene V3 loop nucleotide sequence.Materials and methods. We used blood plasma samples obtained from 76 HIV-infected persons from the Arkhangelsk Region with virological failure of antiretroviral therapy. The nucleotide sequences of the HIV env gene C2-V3-C3 region were studied by PCR followed by sequencing. The genotype of the studied strains was determined based on the analysis of their phylogenetic relations with reference sequences from the international GenBank database, as well as using specialized programs. To predict viral tropism, the Garrido rule and the online bioinformatic tool Geno2Pheno[coreceptor] were used. The Geno2Pheno[coreceptor] algorithm, determines the false positive rate (FPR) based on the analysis of the env gene V3 loop nucleotide sequence. Results and discussion. Significantly lower representation of R5X4/X4-tropic HIV variants in long-term infected persons with subsubtype A6 virus compared to subtype B virus has been shown. For all FPR cut-off algorithms, a significant correlation between subtype and HIV tropism was observed (p=0.0014 and p=0.013 for FPR 10 % and FPR 20 %, respectively). While among subtype B strains, at least 57 % were identified as R5X4/X4-tropic variants (for an FPR of 10 %), including two strains classified as X4-tropic; among HIV subsubtype A6 even at an FPR of 20 %, the frequency of R5X4/X4-tropic samples only slightly exceeded 22 %. It can be assumed that the dynamics of changes in HIV tropism depends on the virus subtype. Significant differences in the distribution of amino acid residues of the V3 region sequences in the examined group between R5-tropic and R5X4/X4-tropic strains of subsubtype A6 for positions 18 (χ2=7.616, p=0.0058), 21 (χ2=7.281, p=0.007), 24 (χ2=5.587, p=0.0181), and 34 (χ2=5.144, p=0.0233) have been demonstrated. Among the R5X4/X4-tropic strains of the A6 subsubtype, amino acid substitutions were registered at positions 6, 19, 21, 26, 29, 30, which were not found in the R5-tropic A6 strains. The high occurrence frequency of a number of mutations previously described as presumably associated with resistance to maraviroc and similar drugs may indicate a natural polymorphism characteristic of the A6 subsubtype, which does not correlate with resistance to CCR5 co-receptor antagonists

The role of infectious agent in development of tooth decay

Aim: to assess the relationship between colonization of the oral cavity with S. mutans and different genotypic characteristics and the degree of tooth decay in children.Materials and methods. 274 children aged 5 to 17 years (153 girls and 121 boys) who received a preventive dental checkup were included in the study. The dental caries experience was assessed by the DMFT index (number of decayed, missing due to caries, and filled teeth), according to WHO recommendations. The plaque was collected with sterile wooden toothpicks from the buccal gingival margin or from fissures of the first molars and placed in 1.5 mL Eppendorf tubes, and then plated on Mitis Salivarius Agar medium (HiMedia, India). 481 strains of S. mutans were selected for further study. DNA was extracted by an express method. Amplification was performed in the CFX-96 thermal cycler (Bio-Rad, USA). Serotyping was performed by multiplex PCR. PCR products were analyzed by gel electrophoresis in 1.5% agarose gel with ethidium bromide (10 mg/mL) manufactured by Helicon, Moscow, and visualized in UV light in transilluminator UVT1 by Biokom. Genotyping was performed according to the methodology (Saarela et al., 1996) with the oligonucleotide primer OPA-02 (5’-TGCCGAGCTG-3’). Strains of S. mutans were studied for the presence of the following genes: gtfB, spaP, cnm, fruA, gtfB, htrA, comE, mutA x(I), mutA (II), mutA (III), nlmAB (IV), adcA, Smu.399, Smu.583, Smu.761, Smu.940c, Smu.1449, Smu.2130.Results. S. mutans was isolated from all the examined children. Dental decay was detected in 82.4% of the children. Among the strains studied, all 4 serotypes were found: in children with a DMFT = 0 only serotypes k and f were detected; the predominant serotype in children with tooth decay was serotype c (74.7%). 19 genotypes of S. mutans were identified. In children without caries (DMFT = 0), S. mutans did not contain the genes spaP, comE, adcA, Smu.2130, Smu.1449, gtfB, htrA. With the increase in the DMFT index, the frequency of their detection increased. 9 genotypes of S. mutans had all 7 virulence factors. In 94.9% of children colonized by these “virulent” genotypes, high DMFT index scores were observed.Conclusion. The data obtained indicate that only a limited number of specific strains have a cariogenic potential. Strains of S. mutans belonging to serotypes e and c with a combination of virulence genes spaP, gtfB, comE, adcA, Smu.2130, Smu.1449, and htrA were isolated from children with tooth decay. Strains without these factors did not cause any damage to the teeth. The degree of tooth decay increases with colonization by several genotypes with the combination of virulence factors described above

Nanoparticle-Delivered 2-PAM for Rat Brain Protection against Paraoxon Central Toxicity

© 2017 American Chemical Society.Solid lipid nanoparticles (SLNs) are among the most promising nanocarriers to target the blood-brain barrier (BBB) for drug delivery to the central nervous system (CNS). Encapsulation of the acetylcholinesterase reactivator, pralidoxime chloride (2-PAM), in SLNs appears to be a suitable strategy for protection against poisoning by organophosphorus agents (OPs) and postexposure treatment. 2-PAM-loaded SLNs were developed for brain targeting and delivery via intravenous (iv) administration. 2-PAM-SLNs displayed a high 2-PAM encapsulation efficiency (∼90%) and loading capacity (maximum 30.8 ± 1%). Drug-loaded particles had a mean hydrodynamic diameter close to 100 nm and high negative zeta potential (-54 to -15 mV). These properties contribute to improve long-term stability of 2-PAM-SLNs when stored both at room temperature (22 °C) and at 4 °C, as well as to longer circulation time in the bloodstream compared to free 2-PAM. Paraoxon-poisoned rats (2 × LD50) were treated with 2-PAM-loaded SLNs at a dose of 2-PAM of 5 mg/kg. 2-PAM-SLNs reactivated 15% of brain AChE activity. Our results confirm the potential use of SLNs loaded with positively charged oximes as a medical countermeasure both for protection against OPs poisoning and for postexposure treatment

Atropisomerism of phosphorus-containing N-aryl carbamates. Experimental and computational data

Studies by 1H NMR spectroscopy and X-ray diffraction analysis revealed hindered rotation of the aromatic substituent about the C Ar-N bond in ortho-substituted (except for o-fluorine-substituted) phosphorus-containing carbamates. The energy barriers to rotation (AG c ≠) and coalescence temperatures (Tc) determined by the coalescence method increase with increasing volume of the ortho substituent. Conformations resulting from rotation of the ortho-substituted aryl group about the CAr-N bond were analyzed by quantum-chemical methods, potential curves were constructed, and differences between the conformational energies and the heights of rotation barriers were estimated. The theoretical rotation barriers change in parallel with the experimental values of ΔGc ≠ however, the theoretical values are much smaller in magnitude

Slow-binding inhibition of acetylcholinesterase by an alkylammonium derivative of 6-methyluracil: Mechanism and possible advantages for myasthenia gravis treatment

© 2016 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.Inhibition of human AChE (acetylcholinesterase) and BChE (butyrylcholinesterase) by an alkylammonium derivative of 6-methyluracil, C-547, a potential drug for the treatment of MG (myasthenia gravis) was studied. Kinetic analysis of AChE inhibition showed that C-547 is a slow-binding inhibitor of type B, i.e. after formation of the initial enzyme•inhibitor complex (Ki = 140 pM), an induced-fit step allows establishment of the final complex (Ki = 22 pM). The estimated koff is low, 0.05 -1 . On the other hand, reversible inhibition of human BChE is a fast-binding process of mixed-type (Ki = 1.77 μM; Ki = 3.17 μM). The crystal structure of mouse AChE complexed with C-547 was solved at 3.13 Å resolution. The complex is stabilized by cation-π , stacking and hydrogenbonding interactions. Molecular dynamics simulations of the binding/dissociation processes of C-547 and C-35 (a noncharged analogue) to mouse and human AChEs were performed. Molecular modelling on mouse and human AChE showed that the slow step results from an enzyme conformational change that allows C-547 to cross the bottleneck in the active-site gorge, followed by formation of tight complex, as observed in the crystal structure. In contrast, the related non-charged compound C-35 is not a slow-binding inhibitor. It does not cross the bottleneck because it is not sensitive to the electrostatic driving force to reach the bottom of the gorge. Thus C-547 is one of the most potent and selective reversible inhibitors of AChE with a long residence time, τ; = 20 min, longer than for other reversible inhibitors used in the treatment of MG. This makes C-547 a promising drug for the treatment of this disease

Combination delivery of two oxime-loaded lipid nanoparticles: Time-dependent additive action for prolonged rat brain protection

© 2018 Elsevier B.V. A novel approach for brain protection against poisoning by organophosphorus agents is developed based on the combination treatment of dual delivery of two oximes. Pralidoxime chloride (2-PAM) and a novel reactivator, 6-(5-(6,7-dimethoxy-3,4-dihydroisoquinolin-2(1H)-yl)pentyl)-3-hydroxy picolinaldehyde oxime (3-HPA), have been loaded in solid-lipid nanoparticles (SLNs) to offer distinct release profile and systemic half-life for both oximes. To increase the therapeutic time window of both oximes, SLNs with two different compartments were designed to load each respective drug. Oxime-loaded SLNs of hydrodynamic diameter between 100 and 160 nm and negative zeta potential (−30 to −25 mV) were stable for a period of 10 months at 4 °C. SLNs displayed longer circulation time in the bloodstream compared to free 3-HPA and free 2-PAM. Oxime-loaded SLNs were suitable for intravenous (iv) administration. Paraoxon-poisoned rats (0.8 × LD50) were treated with 3-HPA-loaded SLNs and 2-PAM+3-HPA-loaded SLNs at the dose of 3-HPA and 2-PAM of 5 mg/kg. Brain AChE reactivation up to 30% was slowly achieved in 5 h after administration of 3-HPA-SLNs. For combination therapy with two oximes, a time-dependent additivity and increased reactivation up to 35% were observed