Enhancing effect of 50 Hz rotating magnetic field on induction of Shiga toxin-converting lambdoid prophages

Palliative effect of rotating magnetic field on glucocorticoid-induced osteonecrosis of the femoral head in rats by regulating osteoblast differentiation

With the substantial increase in the overuse of glucocorticoids (GCs) in clinical medicine, the prevalence of glucocorticoid-induced osteonecrosis of the femoral head (GC-ONFH) continues to rise in recent years. However, the optimal treatment for GC-ONFH remains elusive. Rotating magnetic field (RMF), considered as a non-invasive, safe and effective approach, has been proved to have multiple beneficial biological effects including improving bone diseases. To verify the effects of RMF on GC-ONFH, a lipopolysaccharide (LPS) and methylprednisolone (MPS)-induced invivo rat model, and an MPS-induced invitro cell model have been employed. The results demonstrate that RMF alleviated bone mineral loss and femoral head collapse in GC-ONFH rats. Meanwhile, RMF reduced serum lipid levels, attenuated cystic lesions, raised the expression of anti-apoptotic proteins and osteoprotegerin (OPG), while suppressed the expression of pro-apoptotic proteins and nuclear factor receptor activator-κB (RANK) in GC-ONFH rats. Besides, RMF also facilitated the generation of ALP, attenuated apoptosis and inhibits the expression of pro-apoptotic proteins, facilitated the expression of OPG, and inhibited the expression of RANK in MPS-stimulated MC3T3-E1 cells. Thus, this study indicates that RMF can improve GC-ONFH in rat and cell models, suggesting that RMF have the potential in the treatment of clinical GC-ONFH.

Safety of Exposure to 0.2 T and 4 Hz Rotating Magnetic Field: A Ten-Month Study on C57BL/6 Mice

Amidst the burgeoning interest in rotating magnetic fields (RMF) within biological research, there remains a notable gap in the scientific evidence concerning the long-term safety of RMF. Thus, this study aimed to investigate the safety of protracted exposure to a 0.2 T, 4 Hz RMF over 10 months in mice. Two-month-old female C57BL/6 mice were randomly allocated to either the RMF group (exposed to 0.2 T, 4 Hz real RMF) or the SHAM group (exposed to 0 T, 4 Hz sham RMF). Throughout the experiment, the murine weekly body weights were recorded, and their behavioral traits were assessed via open field tests. In the final month, a comprehensive evaluation of the murine overall health was conducted, encompassing analyses of blood parameters, histomorphological examination of major organs, and skeletal assessments using X-ray and micro-CT imaging. The murine immune system and lipid metabolism were evaluated through immunochip analysis and metabolomics. Notably, no discernible adverse effects with RMF exposure were observed. Murine body weight, locomotor behavior, organ histomorphology, and skeletal health remained unaffected by RMF. Blood analysis revealed subtle changes in hormone and lipid levels between the SHAM and RMF groups, yet these differences did not reach statistical significance. Moreover, RMF led to elevated serum interleukin-28 (IL-28) levels, albeit within the normal range, and modest alterations in serum lipid metabolites. Conclusively, mice exposed to the 0.2 T, 4 Hz RMF for 10 months displayed no significant signs of chronic toxicity, indicating its potential clinical application as a physical therapy.

Advances in bacteriophage-mediated strategies for combating polymicrobial biofilms

Bacteria and fungi tend to coexist within biofilms instead of in planktonic states. Usually, such communities include cross-kingdom microorganisms, which make them harder to remove from abiotic surfaces or infection sites. Additionally, the produced biofilm matrix protects embedded microorganisms from antibiotics, disinfectants, or the host immune system. Therefore, classic therapies based on antibiotics might be ineffective, especially when multidrug-resistant bacteria are causative factors. The complexities surrounding the eradication of biofilms from diverse surfaces and the human body have spurred the exploration of alternative therapeutic modalities. Among these options, bacteriophages and their enzymatic counterparts have emerged as promising candidates, either employed independently or in synergy with antibiotics and other agents. Phages are natural bacteria killers because of mechanisms of action that differ from antibiotics, phages might answer worldwide problems with bacterial infections. In this review, we report the attempts to use bacteriophages in combating polymicrobial biofilms in in vitro studies, using different models, including the therapeutical use of phages. In addition, we sum up the advantages, disadvantages, and perspectives of phage therapy.

Rotating Magnetic Field Mitigates Ankylosing Spondylitis Targeting Osteocytes and Chondrocytes via Ameliorating Immune Dysfunctions

Ankylosing spondylitis (AS) is clinically characterized by bone fusion that is induced by the pathological formation of extra bone. Unfortunately, the fundamental mechanism and related therapies remain unclear. The loss of SHP-2 (encoded by Ptpn11) in CD4-Cre;Ptpn11^f/f mice resulted in the induction of AS-like pathological characteristics, including spontaneous cartilage and bone lesions, kyphosis, and arthritis. Hence, this mouse was utilized as an AS model in this study. As one of the basic physical fields, the magnetic field (MF) has been proven to be an effective treatment method for articular cartilage degeneration. In this study, the effects of a rotating magnetic field (RMF; 0.2 T, 4 Hz) on an AS-like mouse model were investigated. The RMF treatment (2 h/d, 0.2 T, 4 Hz) was performed on AS mice from two months after birth until the day before sampling. The murine specimens were subjected to transcriptomics, immunomics, and metabolomics analyses, combined with molecular and pathological experiments. The results demonstrated that the mitigation of inflammatory deterioration resulted in an increase in functional osteogenesis and a decrease in dysfunctional osteolysis due to the maintenance of bone homeostasis via the RANKL/RANK/OPG signaling pathway. Additionally, by regulating the ratio of CD4+ and CD8+ T-cells, RMF treatment rebalanced the immune microenvironment in skeletal tissue. It has been observed that RMF interventions have the potential to alleviate AS, including by decreasing pathogenicity and preventing disease initiation. Consequently, RMF, as a moderately physical therapeutic strategy, could be considered to alleviate the degradation of cartilage and bone tissue in AS and as a potential option to halt the progression of AS.

Biological effects of rotating magnetic field: A review from 1969 to 2021

As one of the common variable magnetic fields, rotating magnetic field (RMF) plays a crucial role in modern human society. The biological effects of RMF have been studied for over half a century, and various results have been discovered. Several reports have shown that RMF can inhibit the growth of various types of cancer cells in vitro and in vivo and improve clinical symptoms of patients with advanced cancer. It can also affect endogenous opioid systems and rhythm in central nerve systems, promote nerve regeneration and regulate neural electrophysiological activity in the human brain. In addition, RMF can influence the growth and metabolic activity of some microorganisms, alter the properties of fermentation products, inhibit the growth of some harmful bacteria and increase the susceptibility of antibiotic-resistant bacteria to common antibiotics. Besides, there are other biological effects of RMF on blood, bone, prenatal exposure, enzyme activity, immune function, aging, parasite, endocrine, wound healing, and plants. These discoveries demonstrate that RMF have great application potential in health care, medical treatment, fermentation engineering, and even agriculture. However, in some cases like pregnancy, RMF exposure may need to be avoided. Finally, the specific mechanisms of RMF's biological effects remain unrevealed, despite various hypotheses and theories. It does not prevent us from using it for our good.

The use of the electromagnetic field in microbial process bioengineering

An electromagnetic field (EMF) has been shown to have various stimulatory or inhibitory effects on microorganisms. Over the years, growing interest in this topic led to numerous discoveries suggesting the potential applicability of EMF in biotechnological processes. Among these observations are stimulative effects of this physical influence resulting in intensified biomass production, modification of metabolic activity, or pigments secretion. In this review, we present the current state of the art and underline the main findings of the application of EMF in bioprocessing and their practical meaning in process engineering using examples selected from studies on bacteria, archaea, microscopic fungi and yeasts, viruses, and microalgae. All biological data are presented concerning the classification of EMF. Furthermore, we aimed to highlight missing parts of contemporary knowledge and indicate weak spots in the approaches found in the literature.

Rotating Magnetic Field-Assisted Reactor Enhances Mechanisms of Phage Adsorption on Bacterial Cell Surface

Growing interest in bacteriophage research and use, especially as an alternative treatment option for multidrug-resistant bacterial infection, requires rapid development of production methods and strengthening of bacteriophage activities. Bacteriophage adsorption to host cells initiates the process of infection. The rotating magnetic field (RMF) is a promising biotechnological method for process intensification, especially for the intensification of micromixing and mass transfer. This study evaluates the use of RMF to enhance the infection process by influencing bacteriophage adsorption rate. The RMF exposition decreased the t₅₀ and t₇₅ of bacteriophages T4 on Escherichia coli cells and vb_SauM_A phages on Staphylococcus aureus cells. The T4 phage adsorption rate increased from 3.13 × 10⁻⁹ mL × min⁻¹ to 1.64 × 10⁻⁸ mL × min⁻¹. The adsorption rate of vb_SauM_A phages exposed to RMF increased from 4.94 × 10⁻⁹ mL × min⁻¹ to 7.34 × 10⁻⁹ mL × min⁻¹. Additionally, the phage T4 zeta potential changed under RMF from −11.1 ± 0.49 mV to −7.66 ± 0.29 for unexposed and RMF-exposed bacteriophages, respectively.

Application of Magnetically Assisted Reactors for Modulation of Growth and Pyocyanin Production by Pseudomonas aeruginosa

Pseudomonas aeruginosa is a producer of desired secondary metabolites, including pyocyanin. Potential uses of this pigment urge a search for improved production methods. Recent trends in bioprocessing show the potential of the use of electromagnetic fields (EMFs) to influence the growth of microorganisms and even modulate the concentration of bioproducts. Here, we aimed at assessing the influence of rotating magnetic field (RMF) and static magnetic field (SMF) on pyocyanin production, growth rate, and respiration of P. aeruginosa. Moreover, exposure time to EMFs (2, 6, and 12 h) and culture volume (10 and 50 ml) were initially assessed. P. aeruginosa was cultivated in magnetically assisted reactors with 5 and 50 Hz RMF (magnetic induction of 24.32 and 42.64 mT, respectively) and SMF (−17.37 mT). Growth kinetics was assessed with Gompertz equation. The viability was tested using resazurin assay, whereas pyocyanin production by chloroform-HCl methodology. The growth of P. aeruginosa was slightly stimulated by exposure to a RMF with 50 Hz (108% related to the control) and significantly by SMF (132% related to the control), while RMF 5 Hz exposure prolonged the time of inflection (in comparison to RMF 50 Hz and SMF). The 6-h exposure to EMFs resulted in the highest pyocyanin production in comparison to the control, indicating a relationship between exposure time and product concentration. Moreover, cultures led in smaller volumes produced more pyocyanin. Our findings show that the use of different EMF types, frequency, and exposition time and volume could be used interchangeably to obtain different bioprocess aims.

Characterization of a Novel Bacteriophage Henu2 and Evaluation of the Synergistic Antibacterial Activity of Phage-Antibiotics

Staphylococcus aureus phage Henu2 was isolated from a sewage sample collected in Kaifeng, China, in 2017. In this study, Henu2, a linear double-stranded DNA virus, was sequenced and found to be 43,513 bp long with 35% G + C content and 63 putative open reading frames (ORFs). Phage Henu2 belongs to the family Siphoviridae and possesses an isometric head (63 nm in diameter). The latent time and burst size of Henu2 were approximately 20 min and 7.8 plaque forming unit (PFU)/infected cells. The Henu2 maintained infectivity over a wide range of temperature (10–60 °C) and pH values (4–12). Phylogenetic and comparative genomic analyses indicate that Staphylococcus aureus phage Henu2 should be a new member of the family of Siphoviridae class-II. In this paper, Phage Henu2 alone exhibited weak inhibitory activity on the growth of S. aureus. However, the combination of phage Henu2 and some antibiotics or oxides could effectively inhibit the growth of S. aureus, with a decrease of more than three logs within 24 h in vitro. These results provide useful information that phage Henu2 can be combined with antibiotics to increase the production of phage Henu2 and thus enhance the efficacy of bacterial killing.

Phage Therapy: Beyond Antibacterial Action

Until recently, phages were considered as mere “bacteria eaters” with potential for use in combating antimicrobial resistance. The real value of phage therapy assessed according to the standards of evidence-based medicine awaits confirmation by clinical trials. However, the progress in research on phage biology has shed more light on the significance of phages. Accumulating data indicate that phages may also interact with eukaryotic cells. How such interactions could be translated into advances in medicine (especially novel means of therapy) is discussed herein.

Antimicrobial Activity of Al₂O₃, CuO, Fe₃O₄, and ZnO Nanoparticles in Scope of Their Further Application in Cement-Based Building Materials

Nanoparticles were proposed as antibacterial cement admixtures for the production of cement-based composites. Nevertheless, the standards for evaluation of such admixtures still do not indicate which model organisms to use, particularly in regard to the further application of material. Apart from the known toxicity of nanomaterials, in the case of cement-based composites there are limitations associated with the mixing and dispersion of nanomaterials. Therefore, four nanooxides (Al₂O₃, CuO, Fe₃O₄, and ZnO) and seven microorganisms were tested to initially evaluate the applicability of nanooxides in relation to their further use in cement-based composites. Studies of nanoparticles included chemical analysis, microbial growth kinetics, 4- and 24 h toxicity, and biofilm formation assay. Nanooxides showed toxicity against microorganisms in the used concentration, although the populations were able to re-grow. Furthermore, the effect of action was variable even between strains from the same genus. The effect of nanoparticles on biofilms depended on the used strain. Gathered results show several problems that can occur while studying nanoparticles for specific further application. Proper protocols for nanomaterial dispersion prior the preparation of cement-based composites, as well as a standardized approach for their testing, are the fundamental issues that have to be resolved to produce efficient composites.