Chicken Red Blood Cells Research Articles

Side-chain-engineered fluorescent dyes for 3D and long-term dynamic tracking of the plasma membrane in living cells

The plasma membrane involves in many important biological events such as cell fusion and programmed cell death, but most of current plasma membrane probes cannot meet the requirement of long-term specific anchoring to the plasma membrane. Herein, we propose a molecular side-chain engineering strategy to modulate the long-term imaging performance of fluorescent dyes to the plasma membrane by regulating the cell permeability and anchoring ability. A series of FMR dyes with different lengths of side chains were designed and synthesized, and their transmembrane behaviours and staining performance were evaluated in living HeLa cells. We found that short-chain and medium-chain FMR dyes have excellent cell permeability without the labeling ability to the plasma membrane while the long-chain FMR dyes specifically stain the plasma membrane and can be firmly anchored to the plasma membrane for a long period of time. These long-chain FMR dyes have high stain specificality to the plasma membrane, and C10-FMR can be anchored to the plasma membrane of living cells for 2 h, which enables it to continuously monitor dynamic changes of the plasma membrane. The three-dimensional precision imaging of various cells was achieved using C10-FMR, which provides an opportunity to obtain complete information on the three-dimensional spatial morphology of the plasma membrane. The PEG-induced cell fusion of chicken red blood cells and H2O2-induced apoptosis of HeLa cells were monitored by real-time tracking of dynamic changes of the plasma membrane during these processes, which provide solid examples to prove the usefulness of these fluorescent dyes as long-term imaging tools. This work validates the hypothesis that cell permeability of membrane dyes can be readily regulated by tuning the side chains, and provides the effective design strategy of fluorescent dyes for 3D and long-term dynamic tracking of the plasma membrane of diverse animal cells.

Expression of haemagglutinin-neuraminidase of newcastle virus genotype VIII in insect cell Sf9

The hemagglutinin-neuraminidase (HN) protein is the surface glycoprotein of Newcastle disease virus (NDV) which is involved in the process of virus entry into host cells. HN exhibits the capability to induce agglutination of chicken red blood cells, thereby contributing to the viral infection of the host. As a consequence, HN is a potential antigen for the production of subunit vaccines for protecting poultry from NDV infections. In this study, the hn gene coding for the HN antigen of NDV genotype VIII was artificially synthesized, ligated into donor vector pFastBacHT A and integrated into the baculovirus genome for the purpose of HN expression in Spodoptera frugiperda 9 (Sf9) cells. The recombinant HN protein was successfully expressed in Sf9 cells in the SF900 III medium. The expressed recombinant HN protein, with a size of approximately 63 kDa, exhibited hemagglutinin activity (HA) of 4log2 when interacting with chicken erythrocyte fluid. The findings of this study lay the foundation for subsequent research endeavors aimed at the development of Newcastle disease virus (NDV) vaccines tailored for poultry in Vietnam.

Recent H9N2 avian influenza virus lost hemagglutination activity due to a K141N substitution in hemagglutinin.

The H9N2 avian influenza virus (AIV) represents a significant risk to both the poultry industry and public health. Our surveillance efforts in China have revealed a growing trend of recent H9N2 AIV strains exhibiting a loss of hemagglutination activity at 37°C, posing challenges to detection and monitoring protocols. This study identified a single K141N substitution in the hemagglutinin (HA) glycoprotein as the culprit behind this diminished hemagglutination activity. The study evaluated the evolutionary dynamics of residue HA141 and studied the impact of the N141K substitution on aspects such as virus growth, thermostability, receptor-binding properties, and antigenic properties. Our findings indicate a polymorphism at residue 141, with the N variant becoming increasingly prevalent in recent Chinese H9N2 isolates. Although both wild-type and N141K mutant strains exclusively target α,2-6 sialic acid receptors, the N141K mutation notably impedes the virus's ability to bind to these receptors. Despite the mutation exerting minimal influence on viral titers, antigenicity, and pathogenicity in chicken embryos, it significantly enhances viral thermostability and reduces plaque size on Madin-Darby canine kidney (MDCK) cells. Additionally, the N141K mutation leads to decreased expression levels of HA protein in both MDCK cells and eggs. These findings highlight the critical role of the K141N substitution in altering the hemagglutination characteristics of recent H9N2 AIV strains under elevated temperatures. This emphasizes the need for ongoing surveillance and genetic analysis of circulating H9N2 AIV strains to develop effective control and prevention measures.IMPORTANCEThe H9N2 subtype of avian influenza virus (AIV) is currently the most prevalent low-pathogenicity AIV circulating in domestic poultry globally. Recently, there has been an emerging trend of H9N2 AIV strains acquiring increased affinity for human-type receptors and even losing their ability to bind to avian-type receptors, which raises concerns about their pandemic potential. In China, there has been a growing number of H9N2 AIV strains that have lost their ability to agglutinate chicken red blood cells, leading to false-negative results during surveillance efforts. In this study, we identified a K141N mutation in the HA protein of H9N2 AIV to be responsible for the loss of hemagglutination activity. This finding provides insight into the development of effective surveillance, prevention, and control strategies to mitigate the threat posed by H9N2 AIV to both animal and human health.

Virulence Characterization of Faecal Escherichia coli Isolates from Wild Animals

The present study was undertaken to characterize virulence factors associated with fecal Escherichia coli (E.coli) isolates (n=22) from wild animals. Isolates were phenotypically characterized for haemolytic, haemagglutination and gelatinase activity whereas presence of adhesion genes viz. fimH and papG1 was detected genotypically by PCR. Further, whole blood survival assay of E. coli isolates (n=6) was performed using human and goat blood. Isolates exhibited heamolytic (45.45%) as well as gelatinase activity (27.27%) and led mannose sensitive agglutination of human (45.45%), dog (40.90%) and chicken (27.27%) RBC. fimH gene was detected in 27.27% of the isolates whereas none of the isolates was found positive for PapG1 gene. Isolates survived, got adapted and then grew successfully in human as well as goat blood. It can be concluded from present study that wild animals are potent reservoir of virulent E. coli that could adversely affects in-contact human and livestock population.

Virus-inhibitory activity of the antigen complex of opportunistic pathogenic bacteria against SARS-CoV-2

Introduction. The antigen complex of opportunistic pathogenic bacteria (ACOPB) has a protective effect against avian influenza viruses, herpes virus type 2, and other viruses that cause acute respiratory viral infections. In the context of the COVID-19 pandemic, an important task is to find out whether ACOPB has a protective effect against SARS-CoV-2.
 The purpose of the study was to evaluate in vitro the ACOPB virus-inhibitory activity against the Dubrovka laboratory strain of SARS-CoV-2.
 Materials and methods. The study was performed using Vero cell line CCL-81, human peripheral blood mononuclear cells (PBMCs), mouse monoclonal anti-idiotypic antibodies structurally mimicking biological effects of human interferons (IFNs), the Dubrovka laboratory strain of SARS-CoV-2. The infectivity of the virus was assessed by two methods: by virus titration using cell cultures and the limiting dilution method when the results are assessed by a cytopathic effect; the second method was a plaque assay. The in vitro virus inhibition test was performed using the cell culture susceptible to SARS-CoV-2; the mixture containing a specific dose of the virus and a two-fold dilution of ACOPB was transferred to the cell culture after the ACOPB medication had interacted with the virus at 4C for 2 hours. The ACOPB virus-inhibitory activity against SARS-CoV-2 was assessed by the functional activity of / and IFN receptors (RIFN) in human PBMCs induced in vitro by ACOPB and the ACOPB mixture with the specific dose of SARS-CoV-2. The RIFN expression level was measured by the indirect membrane immunofluorescence test.
 Results. Hemagglutination assay using chicken, mouse, guinea pig, and human red blood cells was performed for detection of the SARS-CoV-2 inhibitory protein. The lysate of Vero CCL-81 cells infected with SARS-CoV-2 Dubrovka demonstrated the highest hemagglutination activity with guinea pig red blood cells and low titers of hemagglutination in the virus-containing fluid. The virus inhibition test in the Vero CCL-81 cell culture demonstrated that ACOPB inhibited 10 doses of SARS-CoV-2 Dubrovka with the titer 1 : 32, providing 100% protection of the cell culture for 8 days (the monitoring period). ACOPB induced / and RIFN expression on membranes of human PBMCs in in vitro cultures and decreased RIFN / and expression after its interaction with SARS-CoV-2 Dubrovka.
 Conclusion. The experimental studies including the virus inhibition test in the cell culture susceptible to SARS-CoV-2 Dubrovka and the indirect membrane immunofluorescence assay using monoclonal anti-idiotypic antibodies mimicking IFN-like properties demonstrated that ACOPB had both an immunomodulatory and a virus-inhibitory effect.

Synbiotic supplementation influence select antioxidants markers and immune response of Murrah buffalo calves

Newborn calves undergoes tremendous physiological stress during the early life stage, leading to gut dysbiosis and reduced performance. Synbiotics administration has been shown to play a vital role in immunomodulation by replenishing gut microbiota, thereby conserving and protecting biological membranes against oxidative damage. This study examined the effects of synbiotic supplementation on selected antioxidant markers and immune response in Murrah buffalo calves. A total of twenty-four Murrah buffalo calves aged 5–7 d were enrolled randomly into three treatment groups based on body weight (BW) in a sixty-day feeding trial. Treatments were (1) control (CON); basal diet with no supplementation; (2) SYN1; control + synbiotic formulation 1 (200 mL fermented milk prepared from Lactobacillus acidophilus NCDC15 + 8g Cichorium intybus root powder); (3) SYN2; control + synbiotic formulation 2 (200 mL fermented milk prepared from Limosilactobacillus reuteri BFE7 + 8g Cichorium intybus root powder). Supplementation of SYN1 and SYN2 to calves significantly improved (P < 0.05) the cell-mediated immune response to phytohaemagglutinin-P (CMI; delayed type of hypersensitivity response to PHA-P). At the same time, the humoral immune response to chicken RBC (HIR; antibody titre to C-RBC) was enhanced (P < 0.05) in SYN-fed calves than in CON calves. Moreover, increased superoxide dismutase and catalase activities (P < 0.05) were observed in synbiotic-fed calves compared to CON calves. However, glutathione peroxidase activity was not influenced by SYN supplementation. Overall, the research showed that synbiotic formulations improved the immune system and antioxidant capacity of Murrah buffalo calves, making them less likely to get sick or stressed out during their early lives.

Antimicrobial potential of myricetin-coated zinc oxide nanocomposite against drug-resistant Clostridium perfringens

BackgroundClostridium perfringens (C. perfringens) is an important pathogen in livestock animals and humans causing a wide array of systemic and enteric diseases. The current study was performed to investigate the inhibitory activity of myricetin (MYR), polyvinyl alcohol (PVA), and zinc oxide (ZnO) nanocomposite against growth and α-hemolysin of C. perfringens isolated from beef meat and chicken sources.ResultsThe overall occurrence of C. perfringens was 29.8%. The prevalence of C. perfringens was higher in chicken (38.3%) than in beef meat products (10%). The antimicrobial susceptibility testing revealed that C. perfringens isolates exhibited high resistance levels for metronidazole (93%), bacitracin (89%), penicillin G (84%), and lincomycin (76%). Of note, 1% of C. perfringens isolates were pandrug-resistant (PDR), 4% were extensive drug-resistant (XDR), while 91% were multidrug-resistant. The results of broth microdilution technique revealed that all tested C. perfringens isolates were susceptible to MYR-loaded ZnO/PVA with minimum inhibitory concentrations (MICs) ranged from 0.125 to 2 µg/mL. Moreover, the MYR either alone or combined with the nanocomposite had no cytotoxic activities on chicken red blood cells (cRBCs). Transcriptional modifications of MYR, ZnO, ZnO/PVA, and ZnO/PVA/MYR nanocomposite were determined, and the results showed significant down-regulation of α-hemolysin fold change to 0.5, 0.7, 0.6, and 0.28, respectively compared to the untreated bacteria.ConclusionThis is an in vitro study reporting the antimicrobial potential of MYR-coated ZnO nanocomposite as an effective therapeutic candidate against C. perfringens. An in vivo approach is the next step to provide evidence for applying these alternatives in the treatment and prevention of C. perfringens-associated diseases.

CD99 and the Chicken Alloantigen D Blood System.

The chicken D blood system is one of 13 alloantigen systems found on chicken red blood cells. Classical recombinant studies located the D blood system on chicken chromosome 1, but the candidate gene was unknown. Multiple resources were utilized to identify the chicken D system candidate gene, including genome sequence information from both research and elite egg production lines for which D system alloantigen alleles were reported, and DNA from both pedigree and non-pedigree samples with known D alleles. Genome-wide association analyses using a 600 K or a 54 K SNP chip plus DNA from independent samples identified a strong peak on chicken chromosome 1 at 125-131 Mb (GRCg6a). Cell surface expression and the presence of exonic non-synonymous SNP were used to identify the candidate gene. The chicken CD99 gene showed the co-segregation of SNP-defined haplotypes and serologically defined D blood system alleles. The CD99 protein mediates multiple cellular processes including leukocyte migration, T-cell adhesion, and transmembrane protein transport, affecting peripheral immune responses. The corresponding human gene is found syntenic to the pseudoautosomal region 1 of human X and Y chromosomes. Phylogenetic analyses show that CD99 has a paralog, XG, that arose by duplication in the last common ancestor of the amniotes.

Serological Study of Newcastle Disease in Ducks (Anas javanicus) Slaughtered in East Surabaya Traditional Market

The purpose of this study was to determine the serological study of Newcastle Disease that infects slaughtered ducks (Anas javanicus) at the East Surabaya Traditional Market. This study was conducted from December 2018 to January 2019. A total of 122 samples were collected from four traditional markets in East Surabaya. The Haemagglutination Inhibition (HI) test was used to determine a positive result with an antibody titer of 4 or more. Samples for the HI test were collected from duck serum that had been treated with chicken red blood cells. The results showed 13 (10.65%) of the 122 samples were positive for ND.

Validation of haemagglutination, haemagglutination inhibition and antibody neutralization assays used to determine the titre of CPV -2 virus and anti CVP – 2 egg yolk antibodies

The safety and efficacy of a biological product is determined by the highly variable in-vivo or in-vitro assays. Hence the manufacturers have to minimize the test variabilities to an acceptable limit through optimization of test conditions and validation as per the regulatory guidelines. In this study the test variables were optimized and validated the methods HA, HI and antibody neutralisation assays. During optimisation of HA method, it was observed that no change in the HA titre either due to incubation temperatures (5 ± 3°C, 25 ± 2°C and 37 ± 2°C) or % of RBC used (1% and 0.5%). But the difference was observed for species of RBC used and time taken for HA reaction. CPV – 2 isolate 1 did not show HA activity with chicken RBC and showed agglutination with porcine RBC, whereas isolate 2 was showing HA reaction with both chicken and porcine RBC. During validation studies of HA, HI, CCID50 and antibody neutralization assays the % CV observed was 31, 31, 1.1 and 2.12 respectively which are less than the expected variability of &gt; 50%.

Functional Characterization of Serum Amyloid P Component (SAP) in Host Defense against Bacterial Infection in a Primary Vertebrate.

Serum amyloid P component (SAP), an ancient short pentraxin of the pentraxin family, plays an essential role in resistance to bacterial infection. In this study, the expression and functional characterization of SAP (OnSAP) in Nile tilapia (Oreochromis niloticus), a primary vertebrate, are investigated. The open reading frame of OnSAP is 645 bp of a nucleotide sequence encoding a polypeptide of 214 amino acids. As a calcium-binding protein, the structure and relative motif of OnSAP is highly similar to those of humans, containing amino acid residues Asn, Glu, Gln and Asp. In healthy fish, OnSAP mRNA is extensively distributed in all eleven tissues examined, with the highest level in spleen. The mRNA expression of OnSAP was significantly up-regulated after being challenged with gram-positive bacterium Streptococcus agalactiae and gram-negative bacterium Aeromonas hydrophila in vivo. In addition, recombinant OnSAP ((r)OnSAP) protein had capacities of binding S. agalactiae or A. hydrophila in the presence of Ca2+. Further, (r)OnSAP helped monocytes/macrophages to efficiently phagocytize bacteria. Moreover, the (r)OnSAP was able to enhance the complement-mediated lysis of the chicken red blood cells. Collectively, the evidence of SAP in tilapia, based on the results including its evolutionary conserved protein structure, bacterial binding and agglutination, opsonophagocytosis of macrophage and hemolysis enhancement, enriches a better understanding of the biological functions of the pentraxin family.

Laser polarization driven micromanipulation and reorientation dynamics of an asymmetric shaped microscopic biomaterial using optical tweezers

We present measurements and a theoretical model that describes the dynamics of ellipsoidal shaped, chicken red blood cells (cRBCs) reorienting in an optical trap and demonstrates the ability to control their reorientation through changes in the intensity distribution that results from the different states of the polarization of the trapping laser. We have observed that in linearly polarized light, cRBC, a type of avian RBC, undergoes dual reorientation, with the first reorientation about the cell’s major axis and the second, about its short minor axis, with the major axis aligning with the laser propagation direction at equilibrium. We compute the work done for each of these reorientations and attribute the observed dynamics to a minimization of the energy cost for the particular sequence of the reorientations that we observe. Further, we achieve a controlled second orientation of the major axis along the laser propagation direction by varying the ellipticity of the polarization of the laser. We explain these partial second reorientation results by employing a geometrical optics-based model. Characterizing the dynamics and control of these regular-shaped natural soft materials through optical polarization is relevant in the context of current work in the design and development of microscopic artefacts such as lab-on-a-chip platforms.

Immunization of Broiler Chickens With a Killed Chitosan Nanoparticle Salmonella Vaccine Decreases Salmonella Enterica Serovar Enteritidis Load.

There is a critical need for an oral-killed Salmonella vaccine for broilers. Chitosan nanoparticle (CNP) vaccines can be used to deliver Salmonella antigens orally. We investigated the efficacy of a killed Salmonella CNP vaccine on broilers. CNP vaccine was synthesized using Salmonella enterica serovar Enteritidis (S. Enteritidis) outer membrane and flagella proteins. CNP was stable at acidic conditions by releasing 14% of proteins at pH 5.5. At 17 h post-incubation, the cumulative protein release for CNP was 75% at pH 7.4. Two hundred microliters of PBS with chicken red blood cells incubated with 20 μg/ml CNP released 0% hemoglobin. Three hundred chicks were allocated into 1) Control, 2) Challenge, 3) Vaccine + Challenge. At d1 of age, chicks were spray-vaccinated with PBS or 40 mg CNP. At d7 of age, chicks were orally-vaccinated with PBS or 20 μg CNP/bird. At d14 of age, birds were orally-challenged with PBS or 1 × 107 CFU/bird of S. Enteritidis. The CNP-vaccinated birds had higher antigen-specific IgY/IgA and lymphocyte-proliferation against flagellin (p < 0.05). At 14 days post-infection, CNP-vaccinated birds reversed the loss in gut permeability by 13% (p < 0.05). At 21 days post-infection, the CNP-vaccinated birds decreased S. Enteritidis in the ceca and spleen by 2 Log10 CFU/g, and in the small intestine by 0.6 Log10 CFU/g (p < 0.05). We conclude that the CNP vaccine is a viable alternative to conventional Salmonella poultry vaccines.

Converting of the 2D graphene to its 3D by chicken red blood cells as sheets separator for construction supercapacitor electrode

Here, we report on a facile green and scalable method for the fabrication of porous 3D graphene as a well-known carbon-based material used in many energy storage devices. Chicken red blood cells were used as sheets spacer and heteroatom sources in the construction of 3D graphene. First, the red blood cells were separated from the blood and mixed with graphene oxide. Then, the mixture was freeze-dried and carbonized at 700 °C. The resulted 3D graphene containing heteroatoms was used as a supercapacitor electrode modifier on a glassy carbon electrode and tested with various electrochemical techniques. The supercapacitor electrode showed a specific capacitance of 330 F g−1 at a current density of 1 A g−1, maximum power density of 1958 W kg−1, and maximum energy density of 85 Wh kg−1. Furthermore, the supercapacitive performances were tested in a two-electrode symmetrical system which exhibited a specific capacitance of 238 F g−1 for 1 A g−1. It also showed a power density of 2200 W kg−1 and an appreciable energy density of 160 Wh kg−1. The excellent electrochemical behavior of 3D graphene indicates the promising abilities of the composite for other applications such as biosensors, batteries, electrocatalysts, etc.

Способность экстрактов некоторых съедобных грибов подавлять репродукцию вируса гриппа

In this work, extracts from the mycelium of some xylophytic fungi: Pleurotus eryngii, Auricularia auriculajudae, Tremella fuciformis were obtained, the toxicity of the obtained extracts was evaluated, and the antiviral activity was researched. The influenza virus was grown in the allantois cavity of chicken embryos. The infectious titer of the influenza virus was determined by titration on chicken embryos. The presence of the virus was judged by the reaction of hemagglutinating activity. The virus infectivity titer was calculated using the Reed-Muench method. The hemagglutinating activity of viruses was determined by a standard method using 0.75 % suspension of chicken red blood cells. The main criterion for studying the specific antiviral effect of compounds was the CTI (chemical-therapeutic index), that is determined by the ratio of the average toxic concentration of the substance (TC50) to the average effective viral inhibitory concentration (EC50). The antiviral activity of the obtained extracts was studied on a model of human, animal and bird influenza viruses, in the dose range from 0.025 mcg/ml to 1.25 mcg/ml using the methodological recommendations of the “Guidelines for conducting Preclinical studies of medicines”. While studying the acute toxicity of 3 obtained fungi extracts, it was found that all studied fungi compounds with a single intragastric injection to white mongrel mice, did not show a toxic effect in the studied dose range. During the study of the ability to suppress the reproduction of various strains of the influenza virus, it was found that extracts of the fungi Auricularia auricula-judae and Tremella fuciformis have possessed antiviral properties, and extracts exceed in terms of CTI to commercial anti-influenza drugs.

In Vitro Antiviral Activity of Green Tea Polyphenon-60 against Avian Paramyxoviruses.

Avian paramyxoviruses (APMVs) have caused an economically significant drop in global domestic poultry production because of their high morbidity and mortality rates. Polyphenols are the major components of green tea that have great antiviral effects. This study aimed to evaluate the anti-APMV activities of polyphenon-60. Twelve APMV-1 strains representing three different pathotypes, two strains of APMV-2, one strain of APMV-3, and one strain of APMV-7 were propagated in chicken embryos. To determine the cytotoxic effect, chicken embryo fibroblasts were treated with the test compound in various concentrations. To assess the antiviral properties, time-dependent, dose-dependent, and virulence-dependent experiments were conducted in both cell and chicken embryo models. A reduction in virus titers was measured by the hemagglutination test. The inhibitory effect on virus adsorption to the chicken red blood cell (RBC) surface was examined by the hemagglutination inhibition test. The results showed that lentogenic and mesogenic APMV-1 strains, APMV-3 strain, and APMV-7 strain were significantly inhibited (p < 0.05) by polyphenon-60 at 50 μg/ml, while the 50% cytotoxic concentration of the compound was 345 μg/ml. Polyphenon-60 also exhibited the inhibitory activity against hemagglutination by NDV. Taken together, the results suggest that polyphenon-60 has shown promise as an antiviral agent that has wide safety margins against APMVs, and challenge studies to evaluate its efficacy in chickens are necessary.

Assessment of the hemagglutinating activity of the Porcine orthorubulavirus

Blue eye disease (BED) in pigs is caused by Porcine orthorubulavirus (PRV) of the Paramyxoviridae family. It is an endemic disease in swine production in the central region of Mexico and causes nervous signs and high mortality in suckling pigs, pneumonia in growing pigs, orchitis in boars and mummification during gestation. PRV hemagglutinates most red blood cells (RBCs) of domestic species. For serological diagnosis, the hemagglutination inhibition test is used, and in this test, guinea pig, bovine and chicken RBCs have been commonly used. In this investigation, hemagglutination with PRV was evaluated using the RBCs of seven domestic species (chicken, bovine, horse, pig, dog, guinea pig and rabbit). In the hemagglutination test, the following parameters were evaluated: temperature (25 °C and 37 °C), bottoms of the wells (V and U), erythrocyte concentration (0.5%, 0.75%, and 1%), and reading time (15, 30, 45, 60 and 90 min). Significant differences (P < 0.001) were found in most of the evaluated treatments. The best hemagglutination results were obtained with chicken, bovine and horse RBCs. The hemagglutination titer is higher (2 dilutions) when using chicken RBCs than when using bovine or horse RBCs. If chicken RBCs are used in the inhibition of hemagglutination, the test will be more sensitive, while it is more specific when bovine or horse RBCs are used. The hemagglutination readings are imprecise when using RBCs from dogs, pigs, guinea pigs and rabbits. RBCs from these species should not be used for the diagnosis or investigation of PRV.

Antimicrobial activity of chemically and biologically synthesized silver nanoparticles against some fish pathogens

Pathogens isolated from fish appear to possess considerable antimicrobial resistance and represent a problem for the economy and public health. Natural antimicrobial substitutes to traditional antibiotics represent an essential tool in the fight against antibiotic resistance. Nanotechnology has shown considerable potential in different research fields, and the antimicrobial properties of silver nanoparticles are known. Silver has been used for medical purposes since ancient times because of its bactericidal properties, and the highly reactive surfaces of silver nanoparticles (AgNPs) indicate that they might have a function in antimicrobial applications. This work aimed to study the antimicrobial properties of biologically produced AgNPs from Origanum vulgare leaves compared to chemically produced AgNPs. Both types were characterized by UV–vis spectrophotometry, TEM, and dynamic light scattering and tested against three bacterial strains (Streptococcus agalactiae, and Aeromonas hydrophila, both isolated from Nile tilapia and Vibrio alginolyticus, isolated from sea bass) and three fungal strains (Aspergillus flavus, Fusarium moniliforme, and Candida albicans, all isolated from Nile tilapia). Disk diffusion test and evaluation of ultrastructure changes of tested microorganisms treated with AgNPs by transmission electron microscopy were performed. Moreover, the hemolytic properties of AgNPs were studied on chicken and goat red blood cells. The results obtained declare that the green biological production of silver nanoparticles is safer and more effective than the chemical one; moreover, AgNPs have interesting dose-dependent antimicrobial properties, with better results for biologically produced ones; their effectiveness against tested bacterial and fungal strains opens the way to their use to limit fish diseases, increase economy and improve human health.

Sensitivity of infl uenza virus strains isolated from various regions of Kazakhstan in 2018–2019 to antiviral drugs

The purpose of the study was to examine susceptibility of the Kazakhstan strains of infl uenza A/H1N1 and type B viruses, isolated from various regions of Kazakhstan in 2018–2019, to antiviral drugs. Materials and methods. The susceptibility analysis of 20 strains of infl uenza A/H1N1 and B viruses was carried out with chemotherapeutic agents including Remantadine, Tamifl u, Arbidol, and Ingavirin. Viruses were cultured in the allantoic cavity of developing 10-day-old chicken embryos for 48 hours at 36 °C. The hemagglutinating activity was determined according to the conventional method on 96-well plates using 0.75% chicken red blood cell suspension; the infectivity was calculated by the Reed-Muench method. The sensitivity of virus strains to diff erent concentrations of antiviral drugs was evaluated by the level of reproductive suppression of 100 lg EID50/0.2 ml of virus in chicken embryos. Statistical analysis was performed with the use of Microsoft Offi ce Excel 2010 software. Results. A study of sensitivity to chemotherapeutic agents demonstrated heterogeneity of Kazakhstan 2018–2019 infl uenza A and B viruses population on this feature. The sensitivity to Tamifl u was found in all Kazakhstan strains of infl uenza A/H1N1 virus and three type B strains (inhibitory concentration was 0.44–25.38 μg/mL). The reproduction of most viruses was eff ectively inhibited by tamifl u at a concentration of 0.68–3.23 μg/mL. The inhibitory concentration for the three strains of A/H1N1 virus was 7.23–25.38 μg/mL. Remantadin inhibited the reproduction of viruses at higher doses (12.60–25.55 μg/mL). All viruses under study were resistant to Arbidol and Ingavirin. One type B infl uenza virus was found to be weakly sensitive to Ingavirin. Conclusion. The heterogeneity of the infl uenza virus population in their sensitivity to antiviral drugs indicates the need for constant epidemiological surveillance in order to identify drug-resistant variants.

2018–2019 antiviral drug sensitivity of the influenza virus strains isolated from various regions of Kazakhstan

Influenza is a serious public health problem. The ability of influenza virus to change upon replication is the most serious issue for practical medicine and virology, which can fundamentally alter virus biological properties, such as infectivity and virulence. The high mutational variability of influenza viruses can contribute to rapidly emerging drug resistance. Therefore, the study of antiviral drug sensitivity among influenza viruses is necessary to justify proper drug use for treatment and prevention of influenza infection. The aim of the study was to examine antiviral drug susceptibility of influenza A/H1N1 and B virus strains isolated from various regions of Kazakhstan in the years 2018–2019. Materials and methods. The susceptibility analysis of 20 strains of influenza A/H1N1 and B viruses was carried out by using chemotherapeutic agents including Remantadine, Tamiflu, Arbidol, and Ingavirin. Viruses were cultured in the allantoic cavity of developing 10-day-old chicken embryos for 48 hours at 36оC. The hemagglutinating activity was determined according to the standard method on 96-well plates using 0.75% chicken red blood cell suspension; the infectivity was calculated by the Reed–Muench method. The susceptibility of virus strains to different concentrations of antiviral drugs was evaluated by the level of virus reproductive suppression of 100 lg EID50/0.2 ml in chicken embryos. Statistical analysis was performed using Microsoft Office Excel 2010 software. Results. A study of susceptibility to chemotherapeutic agents demonstrated heterogeneity of influenza A and B virus population isolated in Kazakhstan during the 2018–2019 period. The susceptibility to tamiflu was found in all Kazakhstan strains of influenza A/H1N1 virus and three type B strains (inhibitory concentration was 0.44–25.38 μg/mL). The reproduction of most viruses was effectively inhibited by Tamiflu at a concentration of 0.68–3.23 μg/mL. The inhibitory concentration for three strains of A/H1N1 virus was 7.23–25.38 μg/mL. Remantadine inhibited reproduction of viruses at higher doses (12.60–25.55 μg /mL). All investigated viruses were resistant to Arbidol and Ingavirin. A single type B influenza virus strain was found to be weakly susceptible to Ingavirin. Conclusion. The heterogeneity of influenza virus population in susceptibility to antiviral drugs suggest a need for constant epidemiological surveillance in order to identify drug-resistant variants.