A statistical approach to enhance the productivity of Streptomyces baarensis MH-133 for bioactive compounds

The goal of this study was to use statistical optimization to change the nutritional and environmental conditions so that Streptomyces baarensis MH-133 could make more active metabolites. Twelve trials were used to screen for critical variables influencing productivity using the Placket-Burman Design method. S. baarensis MH-133 is significantly influenced by elicitation, yeast extract, inoculum size, and incubation period in terms of antibacterial activity. A total of 27 experimental trials with various combinations of these factors were used to carry out the response surface technique using the Box-Behnken design. The analyses revealed that the model was highly significant (p < 0.001), with a lack-of-fit of 0.212 and a coefficient determination (R2) of 0.9224. Additionally, the model predicted that the response as inhibition zone diameter would reach a value of 27 mm. Under optimal conditions, S. baarensis MH-133 produced 18.0 g of crude extract to each 35L and was purified with column chromatography. The active fraction exhibiting antibacterial activity was characterized using spectroscopic analysis. The MIC and MBC values varied between 37.5 and 300 μg/ml and 75 and 300 μg/ml, respectively. In conclusion, the biostatistical optimization of the active fraction critical variables, including environmental and nutritional conditions, enhances the production of bioactive molecules by Streptomyces species.

Development of LC-MS/MS analytical method for the rapid determination of Diquat in water and beverages

This study aimed to develop simple, fast, and sensitive methods for the determination of diquat (DQ) in various matrices such as water and beverages. For water, direct injection was tested first, however, the sensitivity of the incurred samples were too low and couldn't possibly achieve the targeted limit of quantification. Hence, dilution with "weaker" injection solvents were tested, and the final conditions involved the dilution of water with acetonitrile (0.4 % ammonium hydroxide) which increased the sensitivity by more than ten times. Nevertheless, the beverages samples needed further treatment to achieve acceptable spiked recovery. The final conditions involved extraction using the aforementioned solvent, followed by heating and partitioning. Both of the methods satisfied the validation requirements, with an average recovery ranging from 85.9 to115 % and associated relative standard deviation (RSD %) within the range 3-8. Further applications on real samples were done to test the levels of contamination.

Iron/Copper/Phosphate nanocomposite as antimicrobial, antisnail, and wheat growth-promoting agent

BACKGROUND

One of the current challenges is to secure wheat crop production to meet the increasing global food demand and to face the increase in its purchasing power. Therefore, the current study aimed to exploit a new synthesized nanocomposite to enhance wheat growth under both normal and drought regime. The effectiveness of this nanocomposite in improving the microbiological quality of irrigation water and inhibiting the snail's growth was also assessed.

RESULTS

Upon the employed one-step synthesis process, a spherical Fe/Cu/P nanocomposite was obtained with a mean particle size of 4.35 ± 1.524 nm. Cu2+, Fe2+, and P4+ were detected in the dried nanocomposite at 14.533 ± 0.176, 5.200 ± 0.208, and 34.167 ± 0.203 mg/ml concentration, respectively. This nanocomposite was found to exert antibacterial activity against Escherichia coli and Salmonella typhi. It caused good inhibition percent against Fusarium oxysporum (43.5 ± 1.47%) and reduced both its germination rate and germination efficiency. The lethal concentration 50 (LC50) of this nanocomposite against Lanistes carinatus snails was 76 ppm. The treated snails showed disturbance in their feeding habit and reached the prevention state. Significant histological changes were observed in snail digestive tract and male and female gonads. Drought stress on wheat's growth was mitigated in response to 100 and 300 ppm treatments. An increase in all assessed growth parameters was reported, mainly in the case of 100 ppm treatment under both standard and drought regimes. Compared to control plants, this stimulative effect was accompanied by a 2.12-fold rise in mitotic index and a 3.2-fold increase in total chromosomal abnormalities.

CONCLUSION

The finding of the current study could be employed to mitigate the effect of drought stress on wheat growth and to enhance the microbiological quality of irrigation water. This is due to the increased efficacy of the newly synthesized Fe/Cu/P nanocomposite against bacteria, fungi, and snails. This methodology exhibits potential for promoting sustainable wheat growth and water resource conservation.

Surf Redfish-Based ZnO-NPs and Their Biological Activity with Reference to Their Non-Target Toxicity

The marine environment is a rich source of bioactive compounds. Therefore, the sea cucumber was isolated from the Red Sea at the Al-Ain Al-Sokhna coast and it was identified as surf redfish (Actinopyga mauritiana). The aqueous extract of the surf redfish was utilized as an ecofriendly, novel and sustainable approach to fabricate zinc oxide nanoparticles (ZnO-NPs). The biosynthesized ZnO-NPs were physico-chemically characterized and evaluated for their possible antibacterial and insecticidal activities. Additionally, their safety in the non-target organism model (Nile tilapia fish) was also investigated. ZnO-NPs were spherical with an average size of 24.69 ± 11.61 nm and had a peak at 350 nm as shown by TEM and UV-Vis, respectively. XRD analysis indicated a crystalline phase of ZnO-NPs with an average size of 21.7 nm. The FTIR pattern showed biological residues from the surf redfish extract, highlighting their potential role in the biosynthesis process. DLS indicated a negative zeta potential (-19.2 mV) of the ZnO-NPs which is a good preliminary indicator for their stability. ZnO-NPs showed larvicidal activity against mosquito Culex pipiens (LC50 = 15.412 ppm and LC90 = 52.745 ppm) and a potent adulticidal effect to the housefly Musca domestica (LD50 = 21.132 ppm and LD90 = 84.930 ppm). Tested concentrations of ZnO-NPs showed strong activity against the 3rd larval instar. Topical assays revealed dose-dependent adulticidal activity against M. domestica after 24 h of treatment with ZnO-NPs. ZnO-NPs presented a wide antibacterial activity against two fish-pathogen bacteria, Pseudomonas aeruginosa and Aeromonas hydrophila. Histopathological and hematological investigations of the non-target organism, Nile tilapia fish exposed to 75-600 ppm ZnO-NPs provide dose-dependent impacts. Overall, data highlighted the potential applications of surf redfish-mediated ZnO-NPs as an effective and safe way to control mosquitoes, houseflies and fish pathogenic bacteria.

A new strategy to integrate silver nanowires with waterborne coating to improve their antimicrobial and antiviral properties

Purpose

This study aims to focus on the preparation and characterization of the silver nanowire (AgNWs), as well as their application as antimicrobial and antivirus activities either with incorporation on the waterborne coating formulation or on their own.

Design/methodology/approach

Prepared AgNWs are characterized by different analytical instruments, such as ultraviolet-visible spectroscope, scanning electron microscope and X-ray diffraction spectrometer. All the paint formulation's physical and mechanical qualities were tested using American Society for Testing and Materials, a worldwide standard test procedure. The biological activities of the prepared AgNWs and the waterborne coating based on AgNWs were investigated. And, their effects on pathogenic bacteria, antioxidants, antiviral activity and cytotoxicity were also investigated.

Findings

The obtained results of the physical and mechanical characteristics of the paint formulation demonstrated the formulations' greatest performance, as well as giving good scrub resistance and film durability. In the antimicrobial activity, the paint did not have any activity against bacterial pathogen, whereas the AgNWs and AgNWs with paint have similar activity against bacterial pathogen with inhibition zone range from 10 to 14 mm. The development of antioxidant and cytotoxicity activity of the paint incorporated with AgNWs were also observed. The cytopathic effects of herpes simplex virus type 1 (HSV-1) were reduced in all three investigated modes of action when compared to the positive control group (HSV-1-infected cells), suggesting that these compounds have promising antiviral activity against a wide range of viruses, including DNA and RNA viruses.

Originality/value

The new waterborne coating based on nanoparticles has the potential to be promising in the manufacturing and development of paints, allowing them to function to prevent the spread of microbial infection, which is exactly what the world requires at this time.

Biosynthesized ZnO-NPs Using Sea Cucumber (Holothuria impatiens): Antimicrobial Potential, Insecticidal Activity and In Vivo Toxicity in Nile Tilapia Fish, Oreochromis niloticus

In this study, a sustainable and eco-friendly method was used to prepare zinc oxide nanoparticles (ZnO-NPs) using a sea cucumber aqueous extract. Then, ZnO-NPs were characterized by instrumental analysis (UV-vis, HR-TEM, XRD, FT-IR, and DLS) and evaluated for their possible antibacterial, antifungal, and insecticidal activities. Additionally, the toxicity of ZnO-NPs was evaluated in vivo against Nile Tilapia (Oreochromis niloticus). The sea cucumber was collected from the Gulf of Suez (Red Sea) at Al-Ain Al-Sokhna coast in Egypt and identified as Holothuria impatiens. The prepared Hi-ZnO-NPs peaked at 350 nm in UV–Vis spectral analysis. They showed quasi-spherical shaped particles with sizes ranging from 13 nm to 47 nm and a predominate size of 26 nm as indicated by HR-TEM. The XRD pattern of Hi-ZnO-NPs revealed a crystalline phase with an average size of 17.2 nm as calculated by Debye–Scherrer equation. FTIR analysis revealed the possible role of H. impatiens biological molecules in the biosynthesis process of ZnO-NPs. Hi-ZnO-NPs showed a negative zeta potential of −19.6 mV, demonstrating moderate stability. Biosynthesized Hi-ZnO-NPs revealed broad antimicrobial activity against Gram-positive bacteria (S. aureus ATCC 25923 and E. feacalis), Gram-negative bacteria (S. typhi, K. pneumonia and E. coli), and filamentous fungi (Aspergillus niger). Hi-ZnO-NPs demonstrated larvicidal activity against the mosquito, Culex pipiens (LC50 = 2.756 ppm and LC90 = 9.294 ppm), and adulticidal action against the housefly, Musca domestica (LD50 = 4.285 ppm and LD90 = 22.847 ppm). Interestingly, Hi-ZnO-NPs did not show mortality effects against Nile tilapia fish (Oreochromis niloticus), highlighting the potential safety of Hi-ZnO-NPs to highly exposed, non-target organisms. However, histopathological and hematological investigations provided dose-dependent impacts of Hi-ZnO-NPs to Nile tilapia. Overall, data provide an eco-friendly approach for synthesizing novel Hi-ZnO-NPs with multiple biomedical properties and potentially low toxicity to Nile tilapia fish.

Biostimulation of tomato growth and biocontrol of Fusarium wilt disease using certain endophytic fungi

BACKGROUND

Tomato plant (Solanum lycopersicum L.) suffers from numerous fungal pathogens that cause damage to yeild production qualitatively and quantitatively. One of the most destructive disease of tomato is Fusarium wilt that caused by soil borne fungus called F. oxysporum.

METHODS

In this study, the anti-Fusarium capabilities of the foliar application of fungal endophytes extracts have been investigated on tomato under Fusarium challenges. Antifungal assay, inhibition of conidial germination, disease severity, photosynthetic pigments, osmolytes, secondary metabolites, oxidative stress, peroxidase (POD) and polyphenol oxidases (PPO) isozymes were tested for potential resistance of tomato growing under Fusarium infection.

RESULTS

Ethyl acetate extracts of A. flavus MZ045563, A. fumigatus MZ045562 and A. nidulans MZ045561 exhibited antifungal activity toward F. oxysporum where inhibition zone diameters were 15, 12 and 20 mm, respectively. Moreover, extracts of all fungal isolates at concentration 7.5 mg/mL reduced conidia germination from 94.4 to 100%. Fusarium infection caused a destructive effects on tomato plant, high severity desiese index 84.37%, reduction in growth parameters, photosynthetic pigments, and soluble protein. However, contents of proline, total phenol, malondialdehyde (MDA), hydrogen peroxide (H₂O₂) and antioxidant enzymes activity were increased in tomato plants grown under Fusarium wilt. Treatment of healthy or infected tomato plants by ethyl acetate fungal extracts showed improvements in morphological traits, photosynthetic pigments, osmolytes, total phenol and antioxidant enzymes activity. Besides, the harmful impacts of Fusarium wilt disease on tomato plants have also been reduced by lowering MDA and H₂O₂ levels. Also, treated tomato plants showed different responses in number and density of POD and PPO isozymes.

CONCLUSION

It could be suggested that application of ethyl acetate extracts of tested fungal endophytes especially combination of A. flavus, A. nidulans and A. fumigatus could be commercially used as safe biostimulation of tomato plants as well as biofungicide against tomato Fusarium wilt disease.

Antibacterial activity of essential oils for combating colistin-resistant bacteria

OBJECTIVES

Colistin (polymyxin E) is a bactericidal antibiotic used to treat severe infections caused by multidrug-resistant Gram-negative bacteria. The product of the mcr1 gene generates transferrable plasmid-mediated colistin resistance, which has arisen as a worldwide healthcare problem. This study aimed to isolate, and identify colistin-resistant bacteria, and evaluate the ability of essential oils its fights.

METHODS

: Twenty-seven bacterial isolates were collected from patients who were admitted to National Cancer Institute, Cairo, Egypt, and processed by standard microbiological methods. Essential oils were purchased from AB chem company, Egypt, screened for antibacterial, cytotoxic activity, and (GC-MS) analysis.

RESULTS

A total of 5 bacterial isolates were resistant to colistin with minimum inhibitory concentration (MIC) ranging from 6.25->200µg/ml. Cinnamon oil exhibited the highest activity against colistin-resistant strains followed by thyme and eucalyptus oil. The (MIC) of cinnamon oils against resistant strains ranged from 4.88 to 312.5 µg/ml. Moreover, mcr-1 gene expression was extremely down-regulated after treatment of bacterial strains with cinnamon oil and decreased to 20-35-fold. Examination of treated bacterial cells with sub-inhibitory concentrations under transmission electron microscopy showed various abnormalities occurred in most of these cells.

CONCLUSIONS

cinnamon oil exhibits antibacterial activity against colistin-resistant strains, showing as a promising natural alternative in clinical therapy.

New Gd(I)/Cs(III) complexes of benzil‐based thiocarbohydrazone macrocyclic ligand: Chemical synthesis, characterization, and study their biological effectiveness as antibacterial, antioxidant, and antiviral additives for polyurethane surface coating

Germs are transmitted in different ways and remain viable or infectious on metal, glass, wood, fabrics, and plastic surfaces for prolonged periods of time. Thus, sterilizing commonly handled everyday objects and public places with high contamination potential is a major global strategy to combat the spread of pathogenic microorganisms. Consequently, our response is development of durable surface‐active coating embedded with new Gd(I)/Cs(III) complexes that derived from condensation of thiocarbohydrazide and benzil precursors. Chemical structures of these complexes were elucidated by Fourier transform infrared (FTIR), electron impact ionization (EI‐MS), 1H nuclear magnetic resonance (NMR), elemental analysis, and scanning electron microscopy (SEM). Next, the well‐established complexes were physically mixed with wide‐range applicable polyurethane (PU) varnish as potential biocide agents. With laboratory scale, coating material was loaded into stainless steel and wood panels to evaluate the physical and mechanical properties. In comparison with the blank formulation, our additives enhanced the gloss levels of the developed PU from 75 to 80 gloss unit (GU), and the scratch hardness was increased to reach >2 kg. Meanwhile, all the coated films passed the flexibility bend test and showed none flaking in mechanical adhesion test. Consequently, Gd(I) and Cs(III) metal complexes did not show any undesirable side effects on PU coating performance. Concerning biological screening, macrocyclic Gd(I) and Cs(III) complexes as well as the reformulated PU varnish were assayed for their antibacterial, antioxidant, and antiviral activities. Antibacterial activity of the developed PU was slightly increased than the individual treatments of Gd(I)/Cs(III) complexes by 1–2 mm, although the blank PU showed no obvious activity against all the tested bacterial strains. Antiviral overall results indicated that the Gd(I) and Cs(III) complexes demonstrated higher activity than the developed PU samples against ADeno‐7, CV‐B4, and HSV‐1 viruses in all modes of action, and hence these coordinated compounds could be promising virucidal agents with good biocompatibility.

New Series of VEGFR-2 Inhibitors and Apoptosis Enhancers: Design, Synthesis and Biological Evaluation

Background

Cancer is still a major world health threat, causing a high rate of mortality. VEGFR-2 inhibitor anticancer agents are of great significance. However, they showed some serious side effects.

Purpose

To discover new effective and safer anticancer agents, a new series of piperazinylquinoxaline-based derivatives was designed and synthesized on the basis of the pharmacophoric features of VEGFR-2 inhibitor drugs.

Methods

The new candidates were evaluated against A549 lung cancer cells, HepG-2 hepatoma cells, Caco-2 colon cancer cells, MDA breast cancer cells, and VEGFR-2 kinase. Moreover, cell cycle kinetics and apoptosis rates were studied in HepG-2 cells treated with compound 11, which was the most promising candidate.

Results

The new derivatives revealed better antitumor results (IC₅₀ from 6.48 to 38.58 µM) against the aforementioned cancer cell lines than sorafenib. Also, the new candidates showed VEGFR-2 inhibition with IC₅₀ values ranging from 0.19 to 0.60 µM compared to 0.08 µM for sorafenib. Compound 11, meanwhile, showed IC₅₀ values equal to 10.61, 9.52, 12.45, 11.52, and 0.19 µM against the cancer cell lines and VEGFR-2, respectively. Moreover, compound 11 raised the apoptosis rate in HepG-2 cells from 5% to 44% and caused 4, 2.3, and 3-fold increases in BAX/Bcl-2 ratio, caspase-3 level, and P53 expression, respectively, compared to control untreated cells. Finally, the new derivatives displayed the correct binding mode into VEGFR-2 kinase pocket, giving interactions with the essential residues.

Conclusion

This work suggests that compound 11 is a very significant anticancer candidate, and piperazinylquinoxaline is an important scaffold in the development of new potential effective and safer VEGFR-2 inhibitor agents.

Antimicrobial, Antioxidant, Cytotoxic Activities and Phytochemical Analysis of Fungal Endophytes Isolated from Ocimum Basilicum

Fungal endophytes are living inside plants without any harmful effects; the prospecting about them is increased day by day because they can produce bioactive compounds which can be used in different applications. Herein, the current study was aimed to isolate the endophytic fungi from the Ocimum basilicum plant as safe microorganisms and evaluate their biological activities. The results illustrated that three endophytic fungal strains were isolated and identified morphologically and genetically as Aspergillus nidulans, Aspergillus fumigatus, and Aspergillus flavus and deposited in gene bank under accession numbers MZ045561, MZ045562, and MZ045563 respectively. Moreover, cell-free filtrates of endophytic fungal strains were extracted using ethyl acetate, where these crude extracts exhibited promising antimicrobial activity against Staphylococcus aureus, Bacillus cereus, Bacillus subtilis, Escherichia coli, Salmonella typhimurium, Pseudomonas aeruginosa, Klebsiella pneumonia, and Candida albicans at a concentration of 1000 µg/mL. Furthermore, these endophytic strains exhibited a potential antioxidant activity where IC₅₀ of the crude extract of A. nidulans, A. fumigatus, and A. flavus were (166.3, 68.4, and 347.1 µg/mL) and (151.2, 77.9, and 246.3 µg/mL) using DPPH and ABTS methods, respectively. Furthermore, the ethyl acetate crude extracts of these endophytic fungi did not exhibit any cytotoxic effect against Vero and Wi 38 normal cells. GC-MS analysis of the crude extract of A. nidulans, A. fumigatus, and A. flavus indicated the presence of 22, 22, and 20 active compounds, respectively. The major compounds in the fungal extracts are belonging to fatty acids, fatty acid esters, tetrahydrofurans, and sterols. In conclusion, the isolated endophytic A. nidulans, A. fumigatus, and A. flavus from Ocimum basilicum are promising sources for bioactive compounds.

Green Synthesized ZnO Nanoparticles Mediated by Streptomyces plicatus: Characterizations, Antimicrobial and Nematicidal Activities and Cytogenetic Effects

Zinc oxide nanoparticles (ZnO-NPs) are regarded as one of the most promising kinds of materials in a variety of fields, including agriculture. Therefore, this study aimed to biosynthesize and characterize ZnO-NPs and evaluate their different biological activities. Seven isolates of actinomycetes were obtained and screened for ZnO-NPs synthesis. The isolate MK-104 was chosen and identified as the Streptomyces plicatus MK-104 strain. The biosynthesized ZnO-NPs exhibited an absorbance peak at 350 nm and were spherical in shape with an average size of 21.72 ± 4.27 nm under TEM. XRD and DLS methods confirmed these results. The biosynthesized ZnO-NPs demonstrated activity against plant pathogenic microbes such as Erwinia amylovora, Aspergillus flavus, Aspergillus niger, Fusarium oxysporum, Fusarium moniliform and Alternaria alternata, with MIC values ranging from 15.6 to 500 µg/mL. Furthermore, ZnO-NPs had a significant effect on Meloidogyne incognita, with death percentages of 88.2, 93.4 and 96.72% after 24, 48 and 72 h of exposure, respectively. Vicia faba seeds were treated with five concentrations of ZnO-NPs (12.5, 25, 50, 100 and 200 µg/mL). Low-moderate ZnO-NP concentrations (12.5-50 µg/mL) were shown to promote seed germination and seedling development, while the mitotic index (MI) decreased as the dosage of ZnO-NPs increased. Micronuclei (MNs) and the chromosomal abnormality index increased as well.

New combination approaches to combat methicillin-resistant Staphylococcus aureus (MRSA)

The herbal products proved to be more promising antimicrobials even though their antimicrobial activity is milder than commercially available antibiotics. Moreover, herbal drugs may act synergistically with antibiotics to kill microbes. In this study, we aimed to enhance the activity of penicillin against MRSA through combination with the active saponin fraction isolated from the Zygophyllum album plant. Three different types of metabolites (saponins, sterols, and phenolics) have been extracted from Zygophyllum album with ethanol and purified using different chromatographic techniques. The antibacterial activity of crude extract and the separated metabolites were checked against MRSA isolates, Saponin fraction (ZA-S) was only the active one followed by the crude extract. Therefore, the compounds in this fraction were identified using ultra-high-performance liquid chromatography connected to quadrupole time-of-flight mass spectrometry (UHPLC/QTOF-MS) operated in positive and negative ionization modes. UHPLC/QTOF-MS revealed the presence of major six ursane-type tritepenoidal saponins (Quinovic acid, Quinovic acid 3β-O-β-D-quinovopyranoside, Zygophylloside C, Zygophylloside G, Zygophylloside K and Ursolic acid), in addition to Oleanolic acid. Interaction studies between saponin fraction and penicillin against MRSA were performed through the checkerboard method and time-kill assay. According to checkerboard results, only three combinations showed a fractional inhibitory concentration index less than 0.5 at concentrations of (62.5 + 312.5, 62.5 + 156.25, and 62.5 + 78.125 of penicillin and ZA-S, respectively). Time kill assay results showed that the highest reduction in log10 colony-forming unit (CFU)/ml of initial inoculum of MRSA after 24 h occurred by 3.7 at concentrations of 62.5 + 312.5 (µg/µg)/ml of penicillin and ZA-S, respectively. Thus, the combination between saponin fraction of Zygophyllum album and penicillin with these concentrations could be a potential agent against MRSA that can serve as possible model for new antibacterial drug.

Design and synthesis of new 4-(2-nitrophenoxy)benzamide derivatives as potential antiviral agents: molecular modeling and in vitro antiviral screening

Novel benzamide derivatives as anti adenovirus, HSV-1, coxsackievirus, and SARS-CoV-2: in vitro and in silico study.

Structural, physical characteristics and biological activities assessment of scleroglucan from a local strain Athelia rolfsii TEMG

Athelia rolfsii TEMG (MH 236106) an exopolysaccharide (EPS) producing fungal strain was isolated and identified. Extraction, purification, characterization, antimicrobial, antioxidant, antiviral and antitumor activities of the polysaccharide were investigated. It characterized as a homopolysaccharide of glucose with a molecular weight of 345.622 kDa. The identification of the polysaccharide was conducted using scanning electron microscopy, energy dispersive X-ray analysis, ¹H and ¹³C NMR spectra. The existence of β-1,3 and β-1,6 linkages suggests that EPS could be scleroglucan. The purified scleroglucan showed considerable antibacterial and antioxidant activities. The results indicated that, there was no cytotoxicity on normal cell (W138) and no effect on tumor cell lines including HepG2 and PC3 showing IC50 of 5096.83, 5885.80 and 4803.90 μg/mL, respectively. The results showed also that Sclg could reduce the cytopathic effect by 50% (EC₅₀) at 15 and 50 μg/mL of herpes simplex virus type-1 (HSV-1) and influenza virus (H5N1), respectively.