Application of extreme environmental conditions to resuscitation of viable but non culturable E. coli DH5α

The resuscitation of Viable But Non-Culturable (VBNC) state in Escherichia coli DH5α as one of the most usable expression host was investigated. The VBNC state in bacteria is defined as while the cells are alive but unable to grow visibly on nonselective growth medium. After collecting several samples, Non-culturable E. coli DH5α (that has undertaken on various recombinant manipulations) were divided into different groups in order to carry-out different experiments. They were treated to heat shock at 42ºC in different periods of time, different concentration of Bile-salts and NaCl and combinational of these methods. The results showed that the almost of resuscitation treatment had positive effect on reactivation of VBNC E. coli DH5α. The combination of these parameters (various NaCl and bile salts concentration and heat shock method at 42 °C in different time) in a binary manner, also inferred to suitable results. Furthermore, by applying the three stresses simultaneously we achieved optical density up to 0.58 and 9×108 CFU/ml which had presented the best results. The results show that by applying some alterations in the condition of such recombinant E. coli DH5α, the growth path of these bacteria which remain to a VBNC phase can be changed to the normal status

Selective cytotoxicity of a novel immunotoxin based on pulchellin A chain for cells expressing HIV envelope.

Immunotoxins (ITs), which consist of antibodies conjugated to toxins, have been proposed as a treatment for cancer and chronic infections. To develop and improve the ITs, different toxins such as ricin, have been used, aiming for higher efficacy against target cells. The toxin pulchellin, isolated from the Abrus pulchellus plant, has similar structure and function as ricin. Here we have compared two plant toxins, recombinant A chains from ricin (RAC) and pulchellin (PAC) toxins, for their ability to kill HIV Env-expressing cells. In this study, RAC and PAC were produced in E. coli, and chromatographically purified, then chemically conjugated to two different anti-HIV monoclonal antibodies (MAbs), anti-gp120 MAb 924 or anti-gp41 MAb 7B2. These conjugates were characterized biochemically and immunologically. Cell internalization was studied by flow cytometry and confocal microscopy. Results showed that PAC can function within an effective IT. The ITs demonstrated specific binding against native antigens on persistently HIV-infected cells and recombinant antigens on Env-transfected cells. PAC cytotoxicity appears somewhat less than RAC, the standard for comparison. This is the first report that PAC may have utility for the design and construction of therapeutic ITs, highlighting the potential role for specific cell targeting

Photoinduced Photosensitizer-Antibody Conjugates Kill HIV Env-Expressing Cells, Also Inactivating HIV.

HIV-infected cells persist for decades in patients administered with antiretroviral therapy (ART). Meanwhile, an alarming surge in drug-resistant HIV viruses has been occurring. Addressing these issues, we propose the application of photoimmunotherapy (PIT) against not only HIV Env-expressing cells but also HIV. Previously, we showed that a human anti-gp41 antibody (7B2) conjugated to cationic or anionic photosensitizers (PSs) could specifically target and kill the HIV Env-expressing cells. Here, our photolysis studies revealed that the binding of photoimmunoconjugates (PICs) on the membrane of HIV Env-expressing cells is sufficient to induce necrotic cell death due to physical damage to the membrane by singlet oxygen, which is independent of the type of PSs. This finding persuaded us to study the virus photoinactivation of PICs using two HIV-1 strains, X4 HIV-1 NL4-3 and JR-CSF virus. We observed that the PICs could destroy the viral strains, probably via physical damage on the HIV envelope. In conclusion, we report the application of PIT as a possible dual-tool for HIV immunotherapy and ART by killing HIV-expressing cells and cell-free HIV, respectively

VLP-Based COVID-19 Vaccines: An Adaptable Technology against the Threat of New Variants.

Virus-like particles (VLPs) are a versatile, safe, and highly immunogenic vaccine platform. Recently, there are developmental vaccines targeting SARS-CoV-2, the causative agent of COVID-19. The COVID-19 pandemic affected humanity worldwide, bringing out incomputable human and financial losses. The race for better, more efficacious vaccines is happening almost simultaneously as the virus increasingly produces variants of concern (VOCs). The VOCs Alpha, Beta, Gamma, and Delta share common mutations mainly in the spike receptor-binding domain (RBD), demonstrating convergent evolution, associated with increased transmissibility and immune evasion. Thus, the identification and understanding of these mutations is crucial for the production of new, optimized vaccines. The use of a very flexible vaccine platform in COVID-19 vaccine development is an important feature that cannot be ignored. Incorporating the spike protein and its variations into VLP vaccines is a desirable strategy as the morphology and size of VLPs allows for better presentation of several different antigens. Furthermore, VLPs elicit robust humoral and cellular immune responses, which are safe, and have been studied not only against SARS-CoV-2 but against other coronaviruses as well. Here, we describe the recent advances and improvements in vaccine development using VLP technology

Photodynamic viral inactivation assisted by photosensitizers

The deadly viruses, which are spreading worldwide at an alarming rate, are a major challenge for the life sciences. More efficient and cost-effective methods with fewer side effects can provide a good alternative to traditional drug-based methods. Currently, physical phenomena such as light in the form of photodynamic action are increasingly being used to inactivate viruses. Photodynamic inactivation (PDI) uses a photosensitizer (PS), light, and oxygen to generate reactive oxygen species (ROS) to inactivate microorganisms. This article reviews the use of existing PSs, as one of the essential anti-viral agents, and introduces new materials and strategies combined with PDI. Physiochemical properties of PSs and their role in interaction with virus components are discussed. Furthermore, the effectiveness of optical sensitizers with radiation methods to inactivate viruses is highlighted

Viral inactivation by light.

Nowadays, viral infections are one of the greatest challenges for medical sciences and human society. While antiviral compounds and chemical inactivation remain inadequate, physical approaches based on irradiation provide new potentials for prevention and treatment of viral infections, without the risk of drug resistance and other unwanted side effects. Light across the electromagnetic spectrum can inactivate the virions using ionizing and non-ionizing radiations. This review highlights the anti-viral utility of radiant methods from the aspects of ionizing radiation, including high energy ultraviolet, gamma ray, X-ray, and neutron, and non-ionizing photo-inactivation, including lasers and blue light

Corrigendum

Heidari S, Azhdadi SN, Asefnezhad A, Sadraeian M, Montazeri M, Biazar EThe relationship between cellular adhesion and surface roughness for polyurethane modified by microwave plasma radiation. International Journal of Nanomedicine. 2011;6:641-647.The correct spelling of the third author's name is "Asefnejad."Original Articl

Thiolate DNAzymes on Gold Nanoparticles for Isothermal Amplification and Detection of Mesothelioma-derived Exosomal PD-L1 mRNA.

Catalytic DNAzymes have been used for isothermal amplification and rapid detection of nucleic acids, holding the potential for point-of-care testing applications. However, when Subzymes (universal substrate and DNAzyme) are tethered to the polystyrene magnetic microparticles via biotin-streptavidin bonds, the residual free Subzymes are often detached from the microparticle surface, which causes a significant degree of false positives. Here, we attached dithiol-modified Subzyme to gold nanoparticle and improved the limit of detection (LoD) by 200 times compared to that using magnetic microparticles. As a proof of concept, we applied our new method for the detection of exosomal programed cell-death ligand 1 (PD-L1) RNA. As the classical immune checkpoint, molecule PD-L1, found in small extracellular vesicles (sEVs, traditionally called exosomes), can reflect the antitumor immune response for predicting immunotherapy response. We achieved the LoD as low as 50 fM in detecting both the RNA homologous to the PD-L1 gene and exosomal PD-L1 RNAs extracted from epithelioid and nonepithelioid subtypes of mesothelioma cell lines, which only takes 8 min of reaction time. As the first application of isothermal DNAzymes for detecting exosomal PD-L1 RNA, this work suggests new point-of-care testing potentials toward clinical translations

Characterization and in vitro probiotic assessment of potential indigenous Bacillus strains isolated from soil rhizosphere

BACKGROUND: Probiotics mainly Bacillus species can be advantageous to the host by promoting its intestinal balance. Attempts were made to isolate and identify Bacillus strains from rhizosphere environment. METHODS: The in vitro probiotic criteria were used for screening and characterizing potential Bacillus probiotics. Morphological, physiological and biochemical characteristics as well as 16S rRNA gene sequence analysis were utilized for identification of the isolates. Seven isolates were chosen based on withstanding to acidic condition (pH 2.5) and various bile salt concentrations (1-4%(w/v)). RESULTS: Isolates found to have the least antimicrobial activity against Listeria monocytogenes PTCC 1163, Staphylococcus aureus ATCC 1912 and Bacillus cereus PTCC 1015; however, no activity against Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 25922 was observed. The Bacillus Isolates showed different variation in auto-aggregation features and adhesion to hydrocarbons ranging from 60% to 90% and 10% to 60%, respectively. Excluding isolate 14 that exhibited resistance to penicillin and ampicillin, all the other Bacillus strains were sensitive to the tested antibiotics. All isolates showed relatively low cytotoxic effect on HepG2 cell line except strains 12 and 14. CONCLUSION: Taking together, among the investigated Bacillus isolates, strains 17 and S10 found to be the most promising candidates to fulfill in vitro probiotic specifications

Aspect Ratio of PEGylated Upconversion Nanocrystals Affects the Cellular Uptake In Vitro and In Vivo.

The central nervous system (CNS) is protected by the blood-brain barrier (BBB), which acts as a physical barrier to regulate and prevent the uptake of endogenous metabolites and xenobiotics. However, the BBB prevents most non-lipophilic drugs from reaching the CNS following systematic administration. Therefore, there is considerable interest in identifying drug carriers that can maintain the biostability of therapeutic molecules and target their transport across the BBB. In this regard, upconversion nanoparticles (UCNPs) have become popular as a nanoparticle-based solution to this problem, with the additional benefit that they display unique properties for in vivo visualization. The majority of studies to date have explored basic spherical UCNPs for drug delivery applications. However, the biophysical properties of UCNPs, cell uptake and BBB transport have not been thoroughly investigated. In this study, we described a one-pot seed-mediated approach to precisely control longitudinal growth to produce bright UCNPs with various aspect ratios. We have systematically evaluated the effects of the physical aspect ratios and PEGylation of UCNPs on cellular uptake in different cell lines and an in vivo zebrafish model. We found that PEGylated the original UCNPs can enhance their biostability and cell uptake capacity. We identify an optimal aspect ratio for UCNP uptake into several different types of cultured cells, finding that this is generally in the ratio of 2 (length/width). This data provides a crucial clue for further optimizing UCNPs as a drug carrier to deliver therapeutic agents into the CNS. STATEMENT OF SIGNIFICANCE: The central nervous system (CNS) is protected by the blood-brain barrier (BBB), which acts as a highly selective semipermeable barrier of endothelial cells to regulate and prevent the uptake of toxins and pathogens. However, the BBB prevents most non-lipophilic drugs from reaching the CNS following systematic administration. The proposed research is significant because identifying the aspect ratio of drug carriers that maintains the biostability of therapeutic molecules and targets their transport across the blood-brain barrier (BBB) is crucial for designing an efficient drug delivery system. Therefore, this research provides a vital clue for further optimizing UCNPs as drug carriers to deliver therapeutic molecules into the brain