Hindering the biofilm of microbial pathogens and cancer cell lines development using silver nanoparticles synthesized by epidermal mucus proteins from Clarias gariepinus

Scientists know very little about the mechanisms underlying fish skin mucus, despite the fact that it is a component of the immune system. Fish skin mucus is an important component of defence against invasive infections. Recently, Fish skin and its mucus are gaining interest among immunologists. Characterization was done on the obtained silver nanoparticles Ag combined with Clarias gariepinus catfish epidermal mucus proteins (EMP-Ag-NPs) through UV-vis, FTIR, XRD, TEM, and SEM. Ag-NPs ranged in size from 4 to 20 nm, spherical in form and the angles were 38.10°, 44.20°, 64.40°, and 77.20°, Where wavelength change after formation of EMP-Ag-NPs as indicate of dark brown, the broad band recorded at wavelength at 391 nm. Additionally, the antimicrobial, antibiofilm and anticancer activities of EMP-Ag-NPs was assessed. The present results demonstrate high activity against unicellular fungi C. albicans, followed by E. faecalis. Antibiofilm results showed strong activity against both S. aureus and P. aeruginosa pathogens in a dose-dependent manner, without affecting planktonic cell growth. Also, cytotoxicity effect was investigated against normal cells (Vero), breast cancer cells (Mcf7) and hepatic carcinoma (HepG2) cell lines at concentrations (200-6.25 µg/mL) and current results showed highly anticancer effect of Ag-NPs at concentrations 100, 5 and 25 µg/mL exhibited rounding, shrinkage, deformation and granulation of Mcf7 and HepG2 with IC50 19.34 and 31.16 µg/mL respectively while Vero cells appeared rounded at concentration 50 µg/mL and normal shape at concentration 25, 12.5 and 6.25 µg/ml with IC50 35.85 µg/mL. This study evidence the potential efficacy of biologically generated Ag-NPs as a substitute medicinal agent against harmful microorganisms. Furthermore, it highlights their inhibitory effect on cancer cell lines.

Unveiling biological activities of biosynthesized starch/silver-selenium nanocomposite using Cladosporium cladosporioides CBS 174.62

BACKGROUND AND OBJECTIVES

Microbial cells capability to tolerate the effect of various antimicrobial classes represent a major worldwide health concern. The flexible and multi-components nanocomposites have enhanced physicochemical characters with several improved properties. Thus, different biological activities of biosynthesized starch/silver-selenium nanocomposite (St/Ag-Se NC) were assessed.

METHODOLOGY

The St/Ag-Se NC was biosynthesized using Cladosporium cladosporioides CBS 174.62 (C. cladosporioides) strain. The shape and average particle size were investigated using scanning electron microscope (SEM) and high-resolution transmission electron microscope (HR-TEM), respectively. On the other hand, the St/Ag-Se NC effect on two cancer cell lines and red blood cells (RBCs) was evaluated and its hydrogen peroxide (H2O2) scavenging effect was assessed. Moreover, its effects on various microbial species in both planktonic and biofilm growth forms were examined.

RESULTS

The St/Ag-Se NC was successfully biosynthesized with oval and spherical shape and a mean particle diameter of 67.87 nm as confirmed by the HR-TEM analysis. St/Ag-Se NC showed promising anticancer activity toward human colorectal carcinoma (HCT-116) and human breast cancer (MCF-7) cell lines where IC50 were 21.37 and 19.98 µg/ml, respectively. Similarly, little effect on RBCs was observed with low nanocomposite concentration. As well, the highest nanocomposite H2O2 scavenging activity (42.84%) was recorded at a concentration of 2 mg/ml. Additionally, Staphylococcus epidermidis (S. epidermidis) ATCC 12,228 and Candida albicans (C. albicans) ATCC 10,231 were the highly affected bacterial and fungal strains with minimum inhibitory concentrations (MICs) of 18.75 and 50 µg/ml, respectively. Moreover, the noticeable effect of St/Ag-Se NC on microbial biofilm was concentration dependent. A high biofilm suppression percentage, 87.5% and 68.05%, were recorded with S. epidermidis and Staphylococcus aureus (S. aureus) when exposed to 1 mg/ml and 0.5 mg/ml, respectively.

CONCLUSION

The biosynthesized St/Ag-Se NC showed excellent antioxidant activity, haemocompatibility, and anti-proliferative effect at low concentrations. Also, it exhibited promising antimicrobial and antibiofilm activities.

Synthesis, Optimization, and Characterization of Cellulase Enzyme Obtained from Thermotolerant Bacillus subtilis F3: An Insight into Cotton Fabric Polishing Activity

The efficacy of 40 bacterial isolates obtained from hot spring water samples to produce cellulase enzymes was investigated. As a result, the strain Bacillus subtilis F3, which was identified using traditional and molecular methods, was selected as the most potent for cellulase production. Optimization was carried out using one-factor-at-a-time (OFAT) and BOX-Behnken Design to detect the best conditions for the highest cellulase activity. This was accomplished after an incubation period of 24 h at 45°C and pH 8, with an inoculum size of 1% (v/v), 5 g/l of peptone as nitrogen source, and 7.5 g/l of CMC. Moreover, the best concentration of ammonium sulfate for cellulase enzyme precipitation was 60% followed by purification using a dialysis bag and Sephadex G-100 column chromatography to collect the purified enzyme. The purified cellulase enzyme was characterized by 5.39-fold enrichment, with a specific activity of 54.20 U/mg and a molecular weight of 439 kDa. There were 15 amino acids involved in the purified cellulase, with high concentrations of 160 and 100 mg/l for glycine and proline respectively. The highest stability and activity of the purified cellulase was attained at pH 7 and 50°C in the presence of 150 ppm of CaCl2, NaCl, and ZnO metal ions. Finally, the biopolishing activity of the cellulase enzyme, as indicated by weight loss percentages of the cotton fabric, was dependent on concentration and treatment time. Overall, the thermotolerant B. subtilis F3 strain has the potential to provide highly stable and highly active cellulase enzyme for use in biopolishing of cotton fabrics.

Antibacterial Activity of Green Synthesized Silver Nanoparticles Using Lawsonia inermis Against Common Pathogens from Urinary Tract Infection

New and creative methodologies for the fabrication of silver nanoparticles (Ag-NPs), which are exploited in a wide range of consumer items, are of significant interest. Hence, this research emphasizes the biological approach of Ag-NPs through Egyptian henna leaves (Lawsonia inermis Linn.) extracts and analysis of the prepared Ag-NPs. Plant extract components were identified by gas chromatography mass spectrometry (GC-mass). The analyses of prepared Ag-NPs were carried out through UV-visible (UV-Vis), X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), and Fourier transform infrared (FTIR) analysis. UV-Vis reveals that Ag-NPs have a maximum peak at 460 nm in visible light. Structural characterization recorded peaks that corresponded to Bragg's diffractions for silver nano-crystal, with average crystallite sizes varying from 28 to 60 nm. Antibacterial activities of Ag-NPs were examined, and it is observed that all microorganisms are very sensitive to biologically synthesized Ag-NPs.

Influence of biosynthesized magnesium oxide nanoparticles on growth and physiological aspects of cowpea (Vigna unguiculata L.) plant, cowpea beetle, and cytotoxicity

Recently, agricultural management innovation has incorporated engineered nanoparticles. The current investigation was carried out to produce magnesium oxide nanoparticles (MgONPs) for the first time applying S. cerevisiae extract. FTIR, XRD, HRTEM, and zeta potential analysis were used to characterize the MgONPs. The FTIR data show that the bioactive substances reduce and cap the synthesized MgONPs. The crystalline metallic MgONPs had four significant peaks in the XRD pattern. The size and form of MgONPs were validated by TEM, which exhibited spherical structures with an average size of 27 nm. The effect of various dosages of MgONPs administered to the cowpea (Vigna unguiculata L.) plant on all in vitro parameters was shown to be significant in the study. The concentration 200 ppm was the most significant treatment which increased shoot length, shoot dry-weight and root dry-weight by 27.35%, 45.09%, and 31.91% when compared with the untreated cowpea plants. MgONPs significantly increased photosynthetic pigments, with 150 ppm treatment significantly increasing soluble proteins and carbohydrates. MgONPs effectively treated cowpea C. maculatus, with dose and time-dependent insecticidal activity. MgONPs death rates varied by 82.66% and 100% on fifth day. Biochemical and histopathological studies of rats were investigated. Rats treated with MgONPs showed higher GOT, GPT, Urea levels, but lower creatinine, indicating significant differences. MgONPs-treated rats' liver showed mild to moderate histopathologic changes, including portal blood vessel congestion, lymphocytic cholangitis, and degenerative changes. MgONPs has the potential to improve cowpea development outcomes and suppress grain insects (C. maculatus).

Recent Insights into Nanotechnology in Colorectal Cancer

Colorectal cancer (CRC) is the third cancer among the known causes of cancer that impact people. Although CRC drug options are imperfect, primary detection of CRC can play a key role in treating the disease and reducing mortality. Cancer tissues show many molecular markers that can be used as a new way to advance therapeutic methods. Nanotechnology includes a wide range of nanomaterials with high diagnostic and therapeutic power. Several nanomaterials and nanoformulations can be used to treat cancer, especially CRC. In this review, we discuss recent insights into nanotechnology in colorectal cancer.

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.

Preparation of new surface coating based on modified oil-based polymers blended with ZnO and CuZnO NPs for steel protection

In our paper, we have synthesized modified PEA and alkyd resin by replacing the new source of polyol (SDEA) which was confirmed by different analyses such as IR, and 1HNMR spectra. A series of conformal, novel, low-cost, and eco-friendly hyperbranched modified alkyd and PEA resins were fabricated with bio ZnO, CuO/ZnO) NPs through an ex-situ method for mechanical and anticorrosive coatings. The synthesized biometal oxides NPs and its composite modified alkyd and PEA were confirmed by FTIR, SEM with EDEX, TEM, and TGA, and can be stably dispersed into modified alkyd and PEA resins at a low weight fraction of 1%. The nanocomposite coating was also subjected to various tests to determine their surface adhesion, which ranged from (4B-5B), physico-mechanical characteristics such as scratch hardness, which improved from < 1.5 to > 2 kg, gloss (100-135) Specific gravity (0.92-0.96) and also chemical resistance test which passed for water, acid, and solvent except alkali, was poor because of the hydrolyzable ester group in the alkyd and PEA resins. The anti-corrosive features of the nanocomposites were investigated through salt spray tests in 5 wt % NaCl. The results indicate that well-dispersed bio ZnO and CuO/ZnO) NPs (1.0%) in the interior of the hyperbranched alkyd and PEA matrix improve the durability and anticorrosive attributes of the composites, such as degree of rusting, which ranged from 5 to 9, blistering size ranged from 6 to 9, and finally, scribe failure, which ranged from 6 to 9 mm. Thus, they exhibit potential applications in eco- friendly surface coatings. The anticorrosion mechanisms of the nanocomposite alkyd and PEA coating were attributed to the synergistic effect of bio ZnO and (CuO/ZnO) NPs and the prepared modified resins are highly rich in nitrogen elements, which might be regarded as a physical barrier layer for steel substrates.

A mini review on green nanotechnology and its development in biological effects

The utilization of living organisms for the creation of inorganic nanoscale particles is a potential new development in the realm of biotechnology. An essential milestone in the realm of nanotechnology is the process of creating dependable and environmentally acceptable metallic nanoparticles. Due to its increasing popularity and ease, use of ambient biological resources is quickly becoming more significant in this field of study. The phrase "green nanotechnology" has gained a lot of attention and refers to a variety of procedures that eliminate or do away with hazardous compounds to repair the environment. Green nanomaterials can be used in a variety of biotechnological sectors such as medicine and biology, as well as in the food and textile industries, wastewater treatment and agriculture field. The construction of an updated level of knowledge with utilization and a study of the ambient biological systems that might support and revolutionize the creation of nanoparticles (NPs) are presented in this article.

Characterizations of highly efficient moderately halophilic toluene degrading exiguobacterium mexicanum M7 strain isolated from Egyptian saline sediments

Toluene and other monoaromatic compounds are released into the environment particularly saline habitats due to the inappropriate disposal methods of petroleum products. Studying the bio-removal strategy is required to clean up these hazardous hydrocarbons that threaten all ecosystem life using halophilic bacteria with higher biodegradation efficiency of monoaromatic compounds as a sole carbon and energy source. Therefore, sixteen pure halophilic bacterial isolates were obtained from saline soil of Wadi An Natrun, Egypt, which have the ability to degrade toluene and consume it as the only source of carbon and energy. Amongst these isolates, isolate M7 exhibited the best growth with considerable properties. This isolate was selected as the most potent strain and identified based on phenotypic and genotypic characterizations. The strain M7 was belonging to Exiguobacterium genus and founded to be closely matched to the Exiguobacterium mexicanum with a similarity of 99%. Using toluene as sole carbon source, strain M7 showed good growth at a wide range temperature degree (20-40ºC), pH (5-9), and salt concentrations (2.5-10%, w/v) with optimal growth conditions at 35ºC, pH 8, and 5%, respectively. The biodegradation ratio of toluene was estimated at above optimal conditions and analyzed using Purge-Trap GC-MS. The results showed that strain M7 has the potentiality to degraded 88.32% of toluene within greatly short time (48 h). The current study findings support the potential ability to use strain M7 as a biotechnological tool in many applications such as effluent treatment and toluene waste management.

Preparation and evaluation of antimicrobial thiadiazol azo disperse dyes as colored materials in digital transfer printing ink for printing onto polyester fabric

Purpose

Paper aims to preparation of new acid disperse dyes based on thiadiazol derivatives and evaluation of their use as antimicrobial colorants in digital transfer-printing ink formulations for printing onto polyester fabric substrates.

Design/methodology/approach

New disperse dyes based on 1,3,4 - thiadiazol derivative (dyes 1–3) were prepared and evaluated by different analysis then formulated as colored materials in the ink formulations. The viscosity, dynamic surface tension and particle size distribution of the prepared inks were measured. The printed polyester fabric substrates were tested using a variety of tests, including light fastness, washing, alkali perspiration and Crock fastness, as well as depth of penetration. Density-functional theory (DFT) calculations were carried out at the Becke3-Lee-Yang-parr (B3LYP) level using the 6–311** basis set, and the biological activity of the prepared disperse dyes was investigated.

Findings

The obtained results of the physical of the prepared ink revealed that thiadiazol disperse ink is a promising ink formulation for polyester printing and agrees with the quality of the printed polyester fabric. The optimization geometry for molecular structures agreed with the analysis of these compounds. The HOMO/LUMO and energy gap of the studied system were discussed. The molecular docking analysis showed strong interaction with DNA Gyrase and demonstrated to us the high ability of these inks to act as antimicrobial agents.

Practical implications

The prepared inks containing the prepared thiadiazol disperse dye were high-performance and suitable for this type of printing technique, according to the results. The prepared inks resist the growth of microorganisms and thus increase the ink's storage stability.

Originality/value

The prepared disperse dyes based on 1,3,4 - thiadiazol derivative (dyes 1–3) can be a promising colorant in different applications, like some types of paint formulations and as a colorant in printing of different fabric substrates.

Mitigation of the hyperglycemic effect of streptozotocin-induced diabetes albino rats using biosynthesized copper oxide nanoparticles

Diabetes mellitus is a metabolic disorder described by compromised insulin synthesis or resistance to insulin inside the human body. Diabetes is a persistent metabolic condition defined by elevated amounts of glucose in the bloodstream, resulting in a range of potential consequences. The main purpose of this study was to find out how biosynthesized copper oxide nanoparticles (CuONPs) affect the blood sugar levels of diabetic albino rats induced by streptozotocin (STZ). In the current study, CuONPs were successfully biosynthesized using Saccharomyes cervisiae using an eco-friendly method. Characterization results revealed that biosynthesized CuONPs appeared at 376 nm with a spherical shape with sizes ranging from 4 to 47.8 nm. Furthermore, results illustrated that administration of 0.5 and 5 mg/kg CuONP in diabetic rats showed a significant decrease in blood glucose levels accompanied by elevated insulin levels when compared to the diabetic control group; however, administration of 0.5 mg/kg is the best choice for diabetic management. Furthermore, it was found that the group treated with CuONPs exhibited a noteworthy elevation in the HDL-C level, along with a depletion in triglycerides, total cholesterol, LDL-C, and VLDL-cholesterol levels compared to the diabetic control group. This study found that administration of CuONPs reduced hyperglycemia and improved pancreatic function as well as dyslipidemia in diabetic rats exposed to STZ, suggesting their potential as a promising therapeutic agent for diabetes treatment.

Biosynthesis of Silver and Gold Nanoparticles and Their Efficacy Towards Antibacterial, Antibiofilm, Cytotoxicity, and Antioxidant Activities

The World Health Organization (WHO) reports that the emergence of multidrug-resistant and the slow advent of novel and more potent antitumor and antimicrobial chemotherapeutics continue to be of the highest concern for human health. Additionally, the stability, low solubility, and negative effects of existing drugs make them ineffective. Studies into alternative tactics to tackle such tenacious diseases was sparked by anticancer and antibacterial. Silver (Ag) and gold (Au) nanoparticles (NPs) were created from Trichoderma saturnisporum, the much more productive fungal strain. Functional fungal extracellular enzymes and proteins carried out the activities of synthesis and capping of the generated nano-metals. Characterization was done on the obtained Ag-NPs and Au-NPs through UV-vis, FTIR, XRD, TEM, and SEM. Additionally, versus methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Klebsiella pneumoniae, the antibacterial activities of Ag-NPs and Au-NPs were assessed. In particular, the Ag-NPs were more effective against pathogenic bacteria than Au-NPs. Furthermore, antibiofilm study that shown Au-NPs had activity more than Ag-NPs. Interestingly, applying the DPPH procedure, these noble metallic NPs had antioxidant activity, in which the IC₅₀ for Ag-NPs and Au-NPs was 73.5 μg/mL and 190.0 μg/mL, respectively. According to the cytotoxicity evaluation results, the alteration in the cells was shown as loss of their typical shape, partial or complete loss of monolayer, granulation, shrinking, or cell rounding with IC₅₀ for normal Vero cell were 693.68 μg/mL and 661.24 μg/mL, for Ag-NPs and Au-NPs, respectively. While IC₅₀ for cancer cell (Mcf7) was 370.56 μg/mL and 394.79 μg/mL for Ag-NPs and Au-NPs, respectively. Ag-NPs and Au-NPs produced via green synthesis have the potential to be employed in the medical industry as beneficial nanocompounds.

Mycosynthesis of Hematite (α-Fe2O3) Nanoparticles Using Aspergillus niger and Their Antimicrobial and Photocatalytic Activities

Nanoparticles (NPs) and nanomaterials (NMs) are now widely used in a variety of applications, including medicine, solar energy, drug delivery, water treatment, and pollution detection. Hematite (α-Fe₂O₃) nanoparticles (Hem-NPs) were manufactured in this work by utilizing a cost-effective and ecofriendly approach that included a biomass filtrate of A. niger AH1 as a bio-reducer. The structural and optical properties of Hem-NPs were investigated using X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), and UV-visible and Fourier-transform infrared (FTIR) spectroscopies. The results revealed that all of the studied parameters, as well as their interactions, had a significant impact on the crystallite size. The average diameter size of the biosynthesized Hem-NPs ranged between 60 and 80 nm. The antimicrobial and photocatalytic activities of Hem-NPs were investigated. The antimicrobial results of Hem-NPs revealed that Hem-NPs exhibited antibacterial activity against E. coli, B. subtilis, and S. mutans with MICs of 125, 31.25, and 15.62 µg/mL, respectively. Moreover, Hem-NPs exhibited antifungal activity against C. albicans and A. fumigatus, where the MICs were 2000 and 62.5 µg/mL, respectively. The efficiency of biosynthesized Hem-NPs was determined for the rapid biodegradation of crystal violet (CV) dye, reaching up to 97 percent after 150 min. Furthermore, Hem-NPs were successfully used more than once for biodegradation and that was regarded as its efficacy. In conclusion, Hem-NPs were successfully biosynthesized using A. niger AH1 and demonstrated both antimicrobial activity and photocatalytic activity against CV dye.

Synthesis of Silver Nanocomposite Based on Carboxymethyl Cellulose: Antibacterial, Antifungal and Anticancer Activities

Traditional cancer treatments include surgery, radiation, and chemotherapy. According to medical sources, chemotherapy is still the primary method for curing or treating cancer today and has been a major contributor to the recent decline in cancer mortality. Nanocomposites based on polymers and metal nanoparticles have recently received the attention of researchers. In the current study, a nanocomposite was fabricated based on carboxymethyl cellulose and silver nanoparticles (CMC-AgNPs) and their antibacterial, antifungal, and anticancer activities were evaluated. The antibacterial results revealed that CMC-AgNPs have promising antibacterial activity against Gram-negative (Klebsiella oxytoca and Escherichia coli) and Gram-positive bacteria (Bacillus cereus and Staphylococcus aureus). Moreover, CMC-AgNPs exhibited antifungal activity against filamentous fungi such as Aspergillus fumigatus, A. niger, and A. terreus. Concerning the HepG2 hepatocellular cancer cell line, the lowest IC₅₀ values (7.9 ± 0.41 µg/mL) were recorded for CMC-AgNPs, suggesting a strong cytotoxic effect on liver cancer cells. As a result, our findings suggest that the antitumor effect of these CMC-Ag nanoparticles is due to the induction of apoptosis and necrosis in hepatic cancer cells via increased caspase-8 and -9 activities and diminished levels of VEGFR-2. In conclusion, CMC-AgNPs exhibited antibacterial, antifungal, and anticancer activities, which can be used in the pharmaceutical and medical fields.

Environmental Impacts of Ecofriendly Iron Oxide Nanoparticles on Dyes Removal and Antibacterial Activity

Biosynthesized nanoparticles have a promising future since they are a more environmentally friendly, cost-effective, repeatable, and energy-efficient technique than physical or chemical synthesis. In this work, Purpureocillium lilacinum was used to synthesize iron oxide nanoparticles (Fe₂O₃-NPs). Characterization of mycosynthesized Fe₂O₃-NPs was done by using UV-vis spectroscopy, transmission electron microscope (TEM), dynamic light scattering (DLS), and X-ray diffraction (XRD) analysis. UV-vis gave characteristic surface plasmon resonance (SPR) peak for Fe₂O₃-NPs at 380 nm. TEM image reveals that the morphology of biosynthesized Fe₂O₃-NPs was hexagonal, and their size range between 13.13 and 24.93 nm. From the XRD analysis, it was confirmed the crystalline nature of Fe₂O₃ with average size 57.9 nm. Further comparative study of photocatalytic decolorization of navy blue (NB) and safranin (S) using Fe₂O₃-NPs was done. Fe₂O₃-NPs exhibited potential catalytic activity with a reduction of 49.3% and 66% of navy blue and safranin, respectively. Further, the antimicrobial activity of Fe₂O₃-NPs was analyzed against pathogenic bacteria (Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis, and Staphylococcus aureus). The Fe₂O₃-NPs were clearly more effective on gram-positive bacteria (S. aureus and B. subtilis) than gram-negative bacteria (E. coli and P. aeruginosa). Thus, the mycosynthesized Fe₂O₃-NPs exhibited an ecofriendly, sustainable, and effective route for decolorization of navy blue and safranin dyes and antibacterial activity.

Green Biosynthesis of Selenium Nanoparticles Using Orange Peel Waste: Characterization, Antibacterial and Antibiofilm Activities against Multidrug-Resistant Bacteria

There is an increase of pathogenic multidrug-resistant bacteria globally due to the misuse of antibiotics. Recently, more scientists used metal nanoparticles to counteract antibacterial resistance. In this study, orange peel waste (OPW) was used for selenium nanoparticles’ (Se-NPs) biosynthesis through the green and ecofriendly method, and their applications as antibacterial and antibiofilm agents. Green biosynthesized Se-NPs were characterized using FTIR, XRD, SEM, EDAX, and TEM. Characterization results revealed that biosynthesized Se-NPs were highly crystalline, spherical, and polydisperse, and had sizes in the range of 16–95 nm. The biosynthesized Se-NPs were evaluated as antibacterial and antibiofilm activities against multidrug-resistant bacteria. Results illustrated that Se-NPs exhibited potential antibacterial activity against Gram-positive bacteria (S. aureus ATCC 29213 and biofilm-producing clinical isolates of S. aureus) and Gram-negative bacteria (Pseudomonas aeruginosa PAO1, MDR, biofilm, and quorum-sensing and producing clinical isolates of MDR P. aeruginosa, MDR E. coli, and K. pneumonia). Moreover, results illustrated that S. aureus ATCC 29213 was the most sensitive bacteria to Se-NPs at 1000 µg/mL, where the inhibition zone was 35 mm and MIC was 25 µg/mL. Furthermore, Se-NPs at 0.25 and 0.5 MIC decreased the biofilm significantly. The largest inhibition of biofilm was noticed in MDR K. pneumonia, which was 62% and 92% at 0.25 and 0.5 MIC, respectively. In conclusion, Se-NPs were successfully biosynthesized using OPW through the green method and had promising antibacterial and antibiofilm activity against multidrug-resistant bacteria, which can be used later in fighting resistant bacteria.

Pseudomonas indica-Mediated Silver Nanoparticles: Antifungal and Antioxidant Biogenic Tool for Suppressing Mucormycosis Fungi

Mucormycosis is considered one of the most dangerous invasive fungal diseases. In this study, a facile, green and eco-friendly method was used to biosynthesize silver nanoparticles (AgNPs) using Pseudomonas indica S. Azhar, to combat fungi causing mucormycosis. The biosynthesis of AgNPs was validated by a progressive shift in the color of P. indica filtrate from colorless to brown, as well as the identification of a distinctive absorption peak at 420 nm using UV-vis spectroscopy. Fourier-transform infrared spectroscopy (FTIR) results indicated the existence of bioactive chemicals that are responsible for AgNP production. AgNPs with particle sizes ranging from 2.4 to 53.5 nm were discovered using transmission electron microscopy (TEM). Pattern peaks corresponding to the 111, 200, 220, 311, and 222 planes, which corresponded to face-centered cubic forms of metallic silver, were also discovered using X-ray diffraction (XRD). Moreover, antifungal activity measurements of biosynthesized AgNPs against Rhizopus Microsporus, Mucor racemosus, and Syncephalastrum racemosum were carried out. Results of antifungal activity analysis revealed that the biosynthesized AgNPs exhibited outstanding antifungal activity against all tested fungi at a concentration of 400 µg/mL, where minimum inhibitory concentrations (MIC) were 50, 50, and 100 µg/mL toward R. microsporus, S. racemosum, and M. racemosus respectively. In addition, the biosynthesized AgNPs revealed antioxidant activity, where IC₅₀ was 31 µg/mL when compared to ascorbic acid (0.79 µg/mL). Furthermore, the biosynthesized AgNPs showed no cytotoxicity on the Vero normal cell line. In conclusion, the biosynthesized AgNPs in this study can be used as effective antifungals with safe use, particularly for fungi causing mucormycosis.

Cefotaxime incorporated bimetallic silver-selenium nanoparticles: promising antimicrobial synergism, antibiofilm activity, and bacterial membrane leakage reaction mechanism

In this research, we reported for the first time the simple incorporation of antibiotic cefotaxime (CFM) with the synthesized Ag NPs, Se NPs, and bimetallic Ag–Se NPs by gamma rays, as a promising cost-effective, and eco-friendly method. The synthesized nanocomposites were characterized by UV-Vis. spectroscopy, XRD, EDX, HR-TEM, SEM/mapping, and EDX studies. The antimicrobial synergistic potential was investigated after CFM drug incorporation. Antibiofilm activity, growth curve assay, and effect of UV illumination were examined against some pathogenic microbes. The antibacterial reaction mechanism was evaluated by protein leakage assay and SEM imaging. HRTEM imaging confirmed the spherical shape and an average diameter of 10.95, 20.54, and 12.69 nm for Ag NPs, Se NPs, and Ag–Se NPs, respectively. Ag NPs-CFM, Se NPs-CFM, and Ag–Se NPs-CFM possessed antimicrobial activity against Staphylococcus aureus (40, 42, and 43 mm ZOI, respectively), Escherichia coli (33, 35, and 34 mm ZOI, respectively) and Candida albicans (25, 22, and 23 mm ZOI, respectively). CFM-incorporated Ag–Se NPs were able to inhibit biofilm formation of S. aureus (96.09%), E. coli (98.32%), and C. albicans (95.93%). Based on the promising results, the synthesized nanocomposites showed superior antimicrobial potential at low concentrations and continued-phase durability; they may find use in pharmaceutical, and biomedical applications.

In this research, we reported for the first time the simple incorporation of antibiotic cefotaxime (CFM) with Ag NPs, Se NPs, and bimetallic Ag–Se NPs by gamma rays; as a promising cost-effective, and eco-friendly method.

Green and ecofriendly biosynthesis of selenium nanoparticles using Urtica dioica (stinging nettle) leaf extract: Antimicrobial and anticancer activity

BACKGROUND/GOAL/AIM

Plant extract is affordable and does not require any particular conditions; rapid production of nanoparticles using plants offers more advantages than other approaches. Selenium nanoparticles (SeNPs) have received much attention in the last decade due to SeNPs diverse and different applications. Herein, this study aimed to biosynthesize SeNPs using aqueous extract of Urtica dioica leaf through green and ecofriendly method. Moreover to fully characterize SeNPs using different techniques, and to evaluate it for antimicrobial activity as well as anticancer activity.

MAIN METHODS AND MAJOR RESULTS

SeNPs were biosynthesis using aqueous leaf extract of U. dioica (stinging nettle). The biosynthesized SeNPs were characterized using UV-visible spectroscopy (UV-Vis), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive electron spectroscopy (EDX), transmission electron microscopy (TEM), and thermal-gravimetric analysis (TGA). Antimicrobial and anticancer activities of biosynthesized SeNPs were assessed. Results illustrated that SeNPs exhibited promising antibacterial activity against Gram-positive and Gram-negative bacteria, as well as unicellular and multi-cellular fungi. Moreover, minimal-inhibitory concentration (MIC) of SeNPs against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus were 250, 31.25, and 500 μg mL^-1 , respectively, while were 62.5, 15.62, 31.25, and 7.81 μg mL^-1 against Candida albicans, Aspergillus fumigatus, Aspergillus niger, and Aspergillus flavus, respectively. The cytotoxicity of SeNPs was performed on Vero normal-cell line CCL-81, where IC₅₀ was 173.2 μg mL^-1 .

CONCLUSIONS AND IMPLICATIONS

For the first time, aqueous stinging nettle leaf extract was utilized to biosynthesize SeNPs in a green method. SeNPs have outstanding antimicrobial-activity against pathogenic bacterial and fungal strains. Moreover, SeNPs have promising anticancer activity against HepG2 cancerous cell line without cytotoxicity on Vero normal cell line. Finally, the biosynthesized SeNPs via aqueous extract of stinging nettle leaf exhibited potential antibacterial, antifungal, and anticancer action, making them useful in the medical field.

Biomedical Applications of Mycosynthesized Selenium Nanoparticles Using Penicillium expansum ATTC 36200

In this study, green and eco-friendly biosynthesis of selenium nanoparticles (Se-NPs) were performed using Penicillium expansum ATTC 36200 for multiple biomedical applications. Mycosynthesized Se-NPs were completely characterized using UV, FT-IR, XRD, SEM, and TEM techniques. Se-NPs biosynthesized by P. expansum was characterized as a spherical shape with average size 4 to 12.7 nm. Moreover, Se-NPs were evaluated for multiple biomedical applications as antimicrobial, antioxidant, and anticancer activities and hemocompatibility. Results illustrated that Se-NPs have potential antimicrobial activity against Gram-positive (Bacillus subtilis ATCC6051 and Staphylococcus aureus ATCC23235), Gram-negative bacteria (Escherichia coli ATCC8739and Pseudomonas aeruginosa ATCC9027), fungi (Candida albicans ATCC90028, Aspergillus niger RCMB 02724 and Aspergillus fumigatus RCMB 02568), and antioxidant activity. Additionally, Se-NPs exhibited anticancer activity against PC3 cell line; IC50 was 99.25 μg/mL. Meanwhile, they showed non-hemolytic activity on human RBCs at concentration up to 250 μg/mL. In conclusion, biosynthetic Se-NPs by P. expansum are promising for many safe-use biomedical applications.

Eco-friendly Mycogenic Synthesis of ZnO and CuO Nanoparticles for In Vitro Antibacterial, Antibiofilm, and Antifungal Applications

Mycogenic synthesis of medically applied zinc oxide (ZnO) and copper oxide (CuO) nanoparticles (NPs) were exploited using Penicillium chrysogenum. The biogenesis and capping processes of the produced nano-metals were conducted by functional fungal extracellular enzymes and proteins. The obtained ZnO-NPs and CuO-NPs were characterized. Also, the antibacterial activity and minimum inhibitory concentration (MIC) values of ZnO-NPs and CuO-NPs were determined. Also, antibiofilm and antifungal activities were investigated. Results have demonstrated the ability of the bio-secreted proteins to cape and reduce ZnO and CuO to hexagonal and spherical ZnO-NPs and CuO-NPs with particle size at 9.0-35.0 nm and 10.5-59.7 nm, respectively. Both ZnO-NPs and CuO-NPs showed high antimicrobial activities not only against Gram-positive and Gram-negative bacteria but also against some phytopathogenic fungal strains. Besides this, those NPs showed varied antibiofilm effects against different microorganisms. Quantitative and qualitative analyses indicated that CuO-NPs had an effective antibiofilm activity against Staphylococcus aureus and therefore can be applied in diverse medical devices. Thus, the mycogenic green synthesized ZnO-NPs and CuO-NPs have the potential as smart nano-materials to be used in the medical field to limit the spread of some pathogenic microbes.

Harnessing Bacterial Endophytes for Promotion of Plant Growth and Biotechnological Applications: An Overview

Endophytic bacteria colonize plants and live inside them for part of or throughout their life without causing any harm or disease to their hosts. The symbiotic relationship improves the physiology, fitness, and metabolite profile of the plants, while the plants provide food and shelter for the bacteria. The bacteria-induced alterations of the plants offer many possibilities for biotechnological, medicinal, and agricultural applications. The endophytes promote plant growth and fitness through the production of phytohormones or biofertilizers, or by alleviating abiotic and biotic stress tolerance. Strengthening of the plant immune system and suppression of disease are associated with the production of novel antibiotics, secondary metabolites, siderophores, and fertilizers such as nitrogenous or other industrially interesting chemical compounds. Endophytic bacteria can be used for phytoremediation of environmental pollutants or the control of fungal diseases by the production of lytic enzymes such as chitinases and cellulases, and their huge host range allows a broad spectrum of applications to agriculturally and pharmaceutically interesting plant species. More recently, endophytic bacteria have also been used to produce nanoparticles for medical and industrial applications. This review highlights the biotechnological possibilities for bacterial endophyte applications and proposes future goals for their application.

Efficacy Assessment of Biosynthesized Copper Oxide Nanoparticles (CuO-NPs) on Stored Grain Insects and Their Impacts on Morphological and Physiological Traits of Wheat (Triticum aestivum L.) Plant

Herein, CuO-NPs were fabricated by harnessing metabolites of Aspergillus niger strain (G3-1) and characterized using UV-vis spectroscopy, XRD, TEM, SEM-EDX, FT-IR, and XPS. Spherical, crystallographic CuO-NPs were synthesized in sizes ranging from 14.0 to 47.4 nm, as indicated by TEM and XRD. EDX and XPS confirmed the presence of Cu and O with weight percentages of 62.96% and 22.93%, respectively, at varied bending energies. FT-IR spectra identified functional groups of metabolites that could act as reducing, capping, and stabilizing agents to the CuO-NPs. The insecticidal activity of CuO-NPs against wheat grain insects Sitophilus granarius and Rhyzopertha dominica was dose- and time-dependent. The mortality percentages due to NP treatment were 55-94.4% (S. granarius) and 70-90% (R. dominica). A botanical experiment was done in a randomized block design. Low CuO-NP concentration (50 ppm) caused significant increases in growth characteristics (shoot and root length, fresh and dry weight of shoot and root, and leaves number), photosynthetic pigments (total chlorophylls and carotenoids), and antioxidant enzymes of wheat plants. There was no significant change in carbohydrate or protein content. The use of CuO-NPs is a promising tool to control grain insects and enhance wheat growth performance.

Green Synthesis of Metallic Nanoparticles and Their Prospective Biotechnological Applications: an Overview

The green synthesis of nanoparticles (NPs) using living cells is a promising and novelty tool in bionanotechnology. Chemical and physical methods are used to synthesize NPs; however, biological methods are preferred due to its eco-friendly, clean, safe, cost-effective, easy, and effective sources for high productivity and purity. High pressure or temperature is not required for the green synthesis of NPs, and the use of toxic and hazardous substances and the addition of external reducing, stabilizing, or capping agents are avoided. Intra- or extracellular biosynthesis of NPs can be achieved by numerous biological entities including bacteria, fungi, yeast, algae, actinomycetes, and plant extracts. Recently, numerous methods are used to increase the productivity of nanoparticles with variable size, shape, and stability. The different mechanical, optical, magnetic, and chemical properties of NPs have been related to their shape, size, surface charge, and surface area. Detection and characterization of biosynthesized NPs are conducted using different techniques such as UV-vis spectroscopy, FT-IR, TEM, SEM, AFM, DLS, XRD, zeta potential analyses, etc. NPs synthesized by the green approach can be incorporated into different biotechnological fields as antimicrobial, antitumor, and antioxidant agents; as a control for phytopathogens; and as bioremediative factors, and they are also used in the food and textile industries, in smart agriculture, and in wastewater treatment. This review will address biological entities that can be used for the green synthesis of NPs and their prospects for biotechnological applications.

Endophytic Streptomyces laurentii Mediated Green Synthesis of Ag-NPs with Antibacterial and Anticancer Properties for Developing Functional Textile Fabric Properties

Improvement of the medical textile industry has received more attention recently, especially with widespread of microbial and viral infections. Medical textiles with new properties, such as bacterial pathogens self-cleaning, have been explored with nanotechnology. In this study, an endophytic actinomycetes strain of Streptomyces laurentii R-1 was isolated from the roots of the medicinal plant Achillea fragrantissima. This is used as a catalyst for the mediated biosynthesis of silver nanoparticles (Ag-NPs) for applications in the textile industry. The biosynthesized Ag-NPs were characterized using UV-vis spectroscopy, Fourier transform infrared (FT-IR), transmission electron microscopy (TEM), and X-ray Diffraction (XRD), which confirmed the successful formation of crystalline, spherical metal nanoparticles. The biosynthesized Ag-NPs exhibited broad-spectrum antibacterial activity. Our data elucidated that the biosynthesized Ag-NPs had a highly cytotoxic effect against the cancerous caco-2 cell line. The selected safe dose of Ag-NPs for loading on cotton fabrics was 100 ppm, regarding their antibacterial activity and safe cytotoxic efficacy. Interestingly, scanning electron microscope connected with energy dispersive X-ray spectroscopy (SEM-EDX) of loaded cotton fabrics demonstrated the smooth distribution of Ag-NPs on treated fabrics. The obtained results highlighted the broad-spectrum activity of nano-finished fabrics against pathogenic bacteria, even after 5 and 10 washing cycles. This study contributes a suitable guide for the performance of green synthesized NPs for utilization in different biotechnological sectors.

Optimization of green biosynthesized visible light active CuO/ZnO nano-photocatalysts for the degradation of organic methylene blue dye

Herein, CuO/ZnO nanocomposites at different ratios were successfully synthesized through a green biosynthesis approach. This was performed by harnessing the fungal-secreted enzymes and proteins during the sol-gel process for nanocomposites seed growth. All fabricated nanoparticles/nanocomposites were characterized using Fourier Transform Infra-Red (FT-IR) Spectroscopy, X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM-EDX) and X-ray Photoelectron Spectroscopy (XPS) analyses. The photocatalytic degradation efficacy of the synthesized nanocomposites was evaluated using a cationic methylene blue (MB) dye as a model of reaction. Results obtained from the FT-IR and EDX analyses revealed that CuO-NPs, ZnO-NPs, CuO/ZnO50/50, CuO/ZnO80/20, and CuO/ZnO20/80 were successfully prepared by harnessing the biomass filtrate of Penicillium corylophilum As-1. Furthermore, XRD and TEM revealed the variation in the particle size of the nanocomposites (10-55 nm) with the ratio of the nanoparticles. Notably, the size of the nanocomposites was proportionally increased with an increasing ratio of ZnO-NPs. XPS analysis affirmed the presence of both Cu and Zn in the nanocomposites with varying binding energies compared with individual nanoparticles. Furthermore, a high photo-degradation efficacy was achieved by increasing the ratio of ZnO-NPs in the nanocomposite formulation, and 97% of organic MB dye was removed after 85 min of irradiation using the CuO/ZnO20/80 nanocomposite.

Multifunctional properties of spherical silver nanoparticles fabricated by different microbial taxa

This study addresses the impacts of metabolites from different microbial taxa on the fabrication and multifunctional biological properties of spherical silver nanoparticles (Ag-NPs). Three microbial taxa, a bacterial (Bacillus cereus A1-5), actinomycetes (Streptomyces noursei H1-1), and fungal (Rhizopus stolonifer A6-2) strains were used for Ag-NPs biosynthesis, whereas Streptomyces noursei is demonstrated for the first time. These isolates were identified using either 16S rRNA or ITS gene sequencing. Characterization of Ag-NPs was done using color change analysis, Uv-Vis spectroscopy, FT-IR spectroscopy, XRD, TEM, SEM-EDX, DLS, and Zeta potential analysis. All biosynthesized NPs exhibited spherical shape with different sizes ranged from 6‒50 nm, 6-30 nm and 6-40 nm for NPs obtained by A1-5, H1-1 and A6-2, respectively. The crystalline center cubic face of Ag-NPs was confirmed using XRD at 2θ values 38.08o, 44.27o, 64.41o and 77.36o. FT-IR analysis revealed varied intense absorption peaks for biomolecules required for NPs synthesize by each microbial strain. The stability of spherical Ag-NPs was confirmed due to highly DLS negative surface charge of ‒17.5mV, ‒18.9mV, and ‒15.6mV for NPs synthesized by strains A1-5, H1-1, and A6-2, respectively. Ag-NPs exhibited a broadspectrum of antibacterial activity against Gram-positive and Gram-negative bacteria with varied effectiveness. They also exhibited a cytotoxic effect against cancer cell line (caco-2) in a dose-dependent pattern with IC50 of 8.9 ± 0.5, 5.6 ± 3.0, 11.2 ± 0.5 μg/ml for NPs synthesized by strains A1-5, H1-1, and A6-2, respectively. Moreover, these spherical Ag-NPs showed larvicidal activity against the 3rd instar larvae of the dengue vector Aedes aegypti.

Endophytic actinomycetes Streptomyces spp mediated biosynthesis of copper oxide nanoparticles as a promising tool for biotechnological applications

In this study, two endophytic actinomycetes isolates Oc-5 and Acv-11, were isolated from healthy leaves of medicinal plant Oxalis corniculata L. These isolates were identified as Streptomyces zaomyceticus Oc-5 and Streptomyces pseudogriseolus Acv-11 using 16S rRNA gene sequence. Biomass extract of these strains were used as a greener attempt for synthesis of copper oxide nanoparticles (CuO-NPs). The synthesized NPs were characterized by UV-Vis spectroscopy, Fourier transform infra-red (FT-IR) spectroscopy, X-ray diffraction (XRD)' transmission electron microscopy (TEM), energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS). Green synthesized NPs showed surface plasmon resonance (SPR) absorption band at 400 nm, crystalline nature, spherical-shaped with an average size of 78 nm and 80.0 nm for CuO-NPs synthesized using strain Oc-5 and Acv-11, respectively. The bioactivities of CuO-NPs were evaluated. Results revealed that CuO-NPs exhibited promising antimicrobial activity against prokaryotic and eukaryotic microbial cells (Gram positive bacteria, Gram negative bacteria, unicellular and multicellular fungi). In addition, it showed antimicrobial potential against phyto-pathogenic fungal strains Fusarium oxysporum, Pythium ultimum, Aspergillus niger and Alternaria alternata. We further explored the in vitro antioxidant activity and cytotoxicity for biosynthesized CuO-NPs. The results revealed that' scavenging and total antioxidant activity for NPs synthesized using Streptomyces pseudogriseolus Acv-11 was better than those synthesized by Streptomyces zaomyceticus Oc-5. Also, the morphological changes and cell viability for Vero and Caco-2 cell line due to NPs treatments were assessed using MTT assay method. Furthermore, Larvicidal efficacy against Musca domestica and Culex pipiens was evaluated. The results obtained in this study clearly showed that biosynthesized CuO-NPs exhibited effective bioactivity and, therefore, provide a base for the development of versatile biotechnological applications soon.

In-Vitro cytotoxicity, antibacterial, and UV protection properties of the biosynthesized Zinc oxide nanoparticles for medical textile applications

Nowadays, medical textiles have become the most essential and developing part in human healthcare sector. This work was undertaken with a view to harness the bio-active macromolecules secreted by fungi e.g. proteins and enzymes in bio-synthesis of ZnO nanoparticles for multifunctional textiles such as antibacterial activity and UV protection with considering the cytotoxicity limitation. Herein, the isolated fungus, Aspergillus terreus, was allowed to produce proteins which has affinity to cape ZnO-NPs. Various factors affecting the behavior of the secreted proteins on the formed nanoparticles were investigated. Thorough characterizations of the protein capped ZnO-NPs were performed by the using of UV-Visible spectroscopy, transmission electron microscope (TEM) Fourier Transform-Infra Red (FT-IR) spectroscopy, X-ray diffraction (XRD) analysis and Dynamic light scattering analysis (DLS). Prior treatment of cotton fabrics with ZnO-NPs, the cytotoxicity of the protein capped ZnO-NPs was examined. After that, the antibacterial activity of the ZnO-NPs before and after treating of cotton fabrics, besides, the UV-protection (UPF) properties were investigated. Results obviously demonstrated the ability of the bio-secreted protein to cape and reduce ZnO to spherical ZnO-NPs with particle size lied around 10-45 nm, as indicated form UV-vis., spectra TEM, Zeta sizer, FTIR and XRD. Regarding to the results of cytotoxicity, the treatment of the cotton fabrics with ZnO-NPs were performed at safe dose (20 ppm). At this dose, ZnO-NPs loaded samples exhibited reasonable antibacterial activity against both Gram positive and Gram negative bacteria; besides, good UV-protection with reasonable increase in UVA and UVB blocking values. Indeed, nanotechnology based microbiological active molecules opens up new opportunities for us to explore novel applications in terms of green technology.

Unusual presentation of solitary bone metastasis from breast carcinoma mimicking acute osteomyelitis of the left midtibial shaft

The authors report an unusual presentation of a solitary bone metastasis in the left midtibial shaft with no other skeletal involvement in a patient with breast carcinoma. The incidence of solitary bone metastasis below the knees is rare. Clinically, the lesion was tender when palpated. A bone scan revealed increased blood flow and blood pool activity, with intense midtibial bony uptake in delayed images. These findings are similar to those of acute osteomyelitis. Biopsy revealed bony metastasis from the patient's breast carcinoma.

Discrepancy between Ga-67 citrate and F-18 fluorodeoxyglucose positron emission tomographic scans in pulmonary infection

The authors describe a patient with the acquired immunodeficiency syndrome who had active pulmonary tuberculosis and was receiving anti-tuberculosis treatment. High-grade fever and a right-sided pleural effusion had recently developed. Results of a Ga-67 scan were negative for any focal infection in the chest. Fluorine-18 fluorodeoxyglucose positron emission tomography showed increased uptake in the right lower lung field, which correlated with the diagnosis of concomitant bacterial pneumonia. Anti-tuberculosis treatment can decrease the sensitivity of the Ga-67 scan and could have contributed to this discrepancy. The authors predict that the fluorine-18 fluorodeoxyglucose positron emission tomographic scan will play an important diagnostic role in the management of such a selected group of patients.