Currently available anti-influenza drugs are often associated with limitations such as toxicity and the appearance of drug-resistant strains. Therefore, there is a pressing need for the development of novel, safe and more efficient antiviral agents. In this study, we evaluated the antiviral activity of zinc oxide nanoparticles (ZnO-NPs) and PEGylated zinc oxide nanoparticles against H1N1 influenza virus. The nanoparticles were characterized using the inductively coupled plasma mass spectrometry, x-ray diffraction analysis, and electron microscopy. MTT assay was applied to assess the cytotoxicity of the nanoparticles, and anti-influenza activity was determined by TCID50 and quantitative Real-Time PCR assays. To study the inhibitory impact of nanoparticles on the expression of viral antigens, an indirect immunofluorescence assay was also performed. Post-exposure of influenza virus with PEGylated ZnO-NPs and bare ZnO-NPs at the highest non-toxic concentrations could be led to 2.8 and 1.2 log10 TCID50 reduction in virus titer when compared to the virus control, respectively (P < 0.0001). At the highest non-toxic concentrations, the PEGylated and unPEGylated ZnO-NPs led to inhibition rates of 94.6% and 52.2%, respectively, which were calculated based on the viral loads. There was a substantial decrease in fluorescence emission intensity in viral-infected cell treated with PEGylated ZnO-NPs compared to the positive control. Taken together, our study indicated that PEGylated ZnO-NPs could be a novel, effective, and promising antiviral agent against H1N1 influenza virus infection, and future studies can be designed to explore the exact antiviral mechanism of these nanoparticles.

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Inhibition of H1N1 influenza virus infection by zinc oxide nanoparticles: another emerging application of nanomedicine

Dps, the DNA-binding protein from starved cells, is capable of providing protection to cells during exposure to severe environmental assaults; including oxidative stress and nutritional deprivation. The structure and function of Dps have been the subject of numerous studies and have been examined in several bacteria that possess Dps or a structural/functional homologue of the protein. Additionally, the involvement of Dps in stress resistance has been researched extensively as well. The ability of Dps to provide multifaceted protection is based on three intrinsic properties of the protein: DNA binding, iron sequestration, and its ferroxidase activity. These properties also make Dps extremely important in iron and hydrogen peroxide detoxification and acid resistance as well. Regulation of Dps expression in E. coli is complex and partially dependent on the physiological state of the cell. Furthermore, it is proposed that Dps itself plays a role in gene regulation during starvation, ultimately making the cell more resistant to cytotoxic assaults by controlling the expression of genes necessary for (or deleterious to) stress resistance. The current review focuses on the aforementioned properties of Dps in E. coli, its prototypic organism. The consequences of elucidating the protective mechanisms of this protein are far-reaching, as Dps homologues have been identified in over 1000 distantly related bacteria and Archaea. Moreover, the prevalence of Dps and Dps-like proteins in bacteria suggests that protection involving DNA and iron sequestration is crucial and widespread in prokaryotes.

https://sfamjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2672.2010.04890.x

Structure, function and regulation of the DNA-binding protein Dps and its role in acid and oxidative stress resistance in Escherichia coli: a review.

Glucoamylase is one of the oldest and widely used biocatalysts in food industry. The major application of glucoamylase is the saccharification of partially processed starch/dextrin to glucose, which is an essential substrate for numerous fermentation processes and a range of food and beverage industries. Glucoamylase for commercial purposes has traditionally been produced employing filamentous fungi, although a diverse group of microorganisms is reported to produce glucoamylase, since they secrete large quantities of the enzyme extracellularly. The commercially used fungal glucoamylases have certain limitations such as moderate thermostability, acidic pH requirement, and slow catalytic activity that increase the process cost. Consequently, the search for newer glucoamylases and protein engineering to improve pH and temperature optima leading to amelioration in catalytic efficiency of existing enzymes have been the major areas of research over the years. The present review focuses attention on the recent advances in molecular biology and protein engineering of glucoamylase to improve its production and functional properties including the so far success achieved in isolating mutants with enhanced thermostability and selectivity, higher pH optimum and improved catalytic activity. A comprehensive account is included on the diversity, regulation of production, classification, purification and properties, and potential applications of microbial glucoamylases to provide an overview on all the important aspects of the enzyme.

Microbial glucoamylases: characteristics and applications

Virus infection induces different cellular responses in infected cells. These include cellular stress responses like autophagy and unfolded protein response (UPR). Both autophagy and UPR are connec...

https://tandfonline.com/doi/pdf/10.1080/21505594.2019.1605803

The roles of apoptosis, autophagy and unfolded protein response in arbovirus, influenza virus, and HIV infections

Multiple strains of Campylobacter coli, C. jejuni, C. helveticus, C. lari, C. sputorum, and C. upsaliensis isolated from animal, clinical, or food samples have been analyzed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Whole bacterial cells were harvested from colonies or confluent growth on agar and transferred directly into solvent and then to a spot of dried 3-methoxy-4-hydroxycinnamic acid (matrix). Multiple ions in the 5,000- to 15,000-Da mass range were evident in spectra for each strain; one or two ions in the 9,500- to 11,000-Da range were consistently high intensity. “Species-identifying” biomarker ions (SIBIs) were evident from analyses of multiple reference strains for each of the six species, including the genome strains C. jejuni NCTC 11168 and C. jejuni RM1221. Strains grown on nine different combinations of media and atmospheres yielded SIBI masses within ±5 Da with external instrument calibration. The highest-intensity C. jejuni SIBIs were cytosolic proteins, including GroES, HU/HCj, and RplL. Multiple intraspecies SIBIs, corresponding probably to nonsynonymous nucleotide polymorphisms, also provided some intraspecies strain differentiation. MALDI-TOF MS analysis of 75 additional Campylobacter strains isolated from humans, poultry, swine, dogs, and cats revealed (i) associations of SIBI type with source, (ii) strains previously speciated incorrectly, and (iii) “strains” composed of more than one species. MALDI-TOF MS provides an accurate, sensitive, and rapid method for identification of multiple Campylobacter species relevant to public health and food safety.

Speciation of Campylobacter coli, C. jejuni, C. helveticus, C. lari, C. sputorum, and C. upsaliensis by Matrix-Assisted Laser Desorption Ionization--Time of Flight Mass Spectrometry

Histone-like proteins in bacteria

Purpose Autophagy plays a key role in host defence responses against microbial infections by promoting degradation of pathogens and participating in acquired immunity The interaction between autophagy and viruses is complex, and this pathway is hijacked by several viruses Influenza virus (IV) interferes with autophagy through its replication and increases the accumulation of autophagosomes by blocking lysosome fusion Thus, autophagy could be an effective area for antiviral research Methodology In this study, we evaluated the effect of autophagy on IV replication Two cell lines were transfected with Beclin-1 expression plasmid before (prophylactic approach) and after (therapeutic approach) IV inoculation Results/Key findings Beclin-1 overexpression in the cells infected by virus induced autophagy to 26 % The log10 haemagglutinin titre and TCID50 (tissue culture infective dose giving 50% infection) of replicating virus were measured at 24 and 48 h post-infection In the prophylactic approach, the virus titre was enhanced significantly at 24 h post-infection (P?001), but it was not significantly different from the control at 48 h post-infection In contrast, the therapeutic approach of autophagy induction inhibited the virus replication at 24 and 48 h post-infection Additionally, we showed that inhibition of autophagy using 3-methyladenine reduced viral replication Conclusion This study revealed that the virus (H1N1) titre was controlled in a time-dependent manner following autophagy induction in host cells Manipulation of autophagy during the IV life cycle can be targeted both for antiviral aims and for increasing viral yield for virus production

Autophagy induction regulates influenza virus replication in a time-dependent manner.

To evaluate MDCK and MDCK-SIAT1 cell lines for their ability to produce the yield of influenza virus in different Multiplicities of Infection. Yields obtained for influenza virus H1N1 grown in MDCK-SIAT1 cell was almost the same as MDCK; however, H3N2 virus grown in MDCK-SIAT1 had lower viral titers in comparison with MDCK cells. The optimized MOIs to infect the cells on plates and microcarrier were selected 0.01 and 0.1 for H1N1 and 0.001 and 0.01 for H3N2, respectively. MDCK-SIAT1 cells may be considered as an alternative mean to manufacture cell-based flu vaccine, especially for the human strains (H1N1), due to its antigenic stability and high titer of influenza virus production.

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Maryam Saleh

Papers

Histone-like proteins in bacteria

Autophagy induction regulates influenza virus replication in a time-dependent manner.

Comparison between MDCK and MDCK-SIAT1 cell lines as preferred host for cell culture-based influenza vaccine production.

Biotransformation of alcohols to aldehydes by immobilized cells of Saccharomyces cerevisiae PTCC5080

Expression of the influenza M2 protein in three different eukaryotic cell lines.