Microalgae-mediated bioremediation: current trends and opportunities-a review.

Environmental pollution poses a critical global challenge, and traditional wastewater treatment methods often prove inadequate in addressing the complexity and scale of this issue. On the other hand, microalgae exhibit diverse metabolic capabilities that enable them to remediate a wide range of pollutants, including heavy metals, organic contaminants, and excess nutrients. By leveraging the unique metabolic pathways of microalgae, innovative strategies can be developed to effectively remediate polluted environments. Therefore, this review paper highlights the potential of microalgae-mediated bioremediation as a sustainable and cost-effective alternative to conventional methods. It also highlights the advantages of utilizing microalgae and algae-bacteria co-cultures for large-scale bioremediation applications, demonstrating impressive biomass production rates and enhanced pollutant removal efficiency. The promising potential of microalgae-mediated bioremediation is emphasized, presenting a viable and innovative alternative to traditional treatment methods in addressing the global challenge of environmental pollution. This review identifies the opportunities and challenges for microalgae-based technology and proposed suggestions for future studies to tackle challenges. The findings of this review advance our understanding of the potential of microalgae-based technology wastewater treatment.

A critical review on plastic waste life cycle assessment and management: Challenges, research gaps, and future perspectives.

The global production and consumption of plastics, as well as their deposition in the environment, are experiencing exponential growth. In addition, mismanaged plastic waste (PW) losses into drainage channels are a growing source of microplastic (MP) pollution concern. However, the complete understanding of their environmental implications throughout their life cycle is yet to be fully understood. Determining the potential extent to which MPs contribute to overall ecotoxicity is possible through the monitoring of PW release and MP removal during remediation. Life cycle assessments (LCAs) have been extensively utilized in many comparative analyses, such as comparing petroleum-based plastics with biomass and single-use plastics with multi-use alternatives. These assessments typically yield unexpected or paradoxical results. Nevertheless, there is still a paucity of reliable data and tools for conducting LCAs on plastics. On the other hand, the release and impact of MP have so far not been considered in LCA studies. This is due to the absence of inventory-related data regarding MP releases and the characterization factors necessary to quantify the effects of MP. Therefore, this review paper conducts a comprehensive literature review in order to assess the current state of knowledge and data regarding the environmental impacts that occur throughout the life cycle of plastics, along with strategies for plastic management through LCA.

Recent advances in sustainable hydrogen production from microalgae: Mechanisms, challenges, and future perspectives.

The depletion of fossil fuel reserves has resulted from their application in the industrial and energy sectors. As a result, substantial efforts have been dedicated to fostering the shift from fossil fuels to renewable energy sources via technological advancements in industrial processes. Microalgae can be used to produce biofuels such as biodiesel, hydrogen, and bioethanol. Microalgae are particularly suitable for hydrogen production due to their rapid growth rate, ability to thrive in diverse habitats, ability to resolve conflicts between fuel and food production, and capacity to capture and utilize atmospheric carbon dioxide. Therefore, microalgae-based biohydrogen production has attracted significant attention as a clean and sustainable fuel to achieve carbon neutrality and sustainability in nature. To this end, the review paper emphasizes recent information related to microalgae-based biohydrogen production, mechanisms of sustainable hydrogen production, factors affecting biohydrogen production by microalgae, bioreactor design and hydrogen production, advanced strategies to improve efficiency of biohydrogen production by microalgae, along with bottlenecks and perspectives to overcome the challenges. This review aims to collate advances and new knowledge emerged in recent years for microalgae-based biohydrogen production and promote the adoption of biohydrogen as an alternative to conventional hydrocarbon biofuels, thereby expediting the carbon neutrality target that is most advantageous to the environment.

Potential applications of extremophilic bacteria in the bioremediation of extreme environments contaminated with heavy metals.

Protecting the environment from harmful pollutants has become increasingly difficult in recent decades. The presence of heavy metal (HM) pollution poses a serious environmental hazard that requires intricate attention on a worldwide scale. Even at low concentrations, HMs have the potential to induce deleterious health effects in both humans and other living organisms. Therefore, various strategies have been proposed to address this issue, with extremophiles being a promising solution. Bacteria that exhibit resistance to metals are preferred for applications involving metal removal due to their capacity for rapid multiplication and growth. Extremophiles are a special group of microorganisms that are capable of surviving under extreme conditions such as extreme temperatures, pH levels, and high salt concentrations where other organisms cannot. Due to their unique enzymes and adaptive capabilities, extremophiles are well suited as catalysts for environmental biotechnology applications, including the bioremediation of HMs through various strategies. The mechanisms of resistance to HMs by extremophilic bacteria encompass: (i) metal exclusion by permeability barrier; (ii) extracellular metal sequestration by protein/chelator binding; (iii) intracellular sequestration of the metal by protein/chelator binding; (iv) enzymatic detoxification of a metal to a less toxic form; (v) active transport of HMs; (vi) passive tolerance; (vii) reduced metal sensitivity of cellular targets to metal ions; and (viii) morphological change of cells. This review provides comprehensive information on extremophilic bacteria and their potential roles for bioremediation, particularly in environments contaminated with HMs, which pose a threat due to their stability and persistence. Genetic engineering of extremophilic bacteria in stressed environments could help in the bioremediation of contaminated sites. Due to their unique characteristics, these organisms and their enzymes are expected to bridge the gap between biological and chemical industrial processes. However, the structure and biochemical properties of extremophilic bacteria, along with any possible long-term effects of their applications, need to be investigated further.

Strategies to enhance biohydrogen production from microalgae: A comprehensive review.

Microalgae represent a promising renewable feedstock for the sustainable production of biohydrogen. Their high growth rates and ability to fix carbon utilizing just sunlight, water, and nutrients make them well-suited for this application. Recent advancements have focused on improving microalgal hydrogen yields and cultivation methods. This review aims to summarize recent developments in microalgal cultivation techniques and genetic engineering strategies for enhanced biohydrogen production. Specific areas of focus include novel microalgal species selection, immobilization methods, integrated hybrid systems, and metabolic engineering. Studies related to microalgal strain selection, cultivation methods, metabolic engineering, and genetic manipulations were compiled and analyzed. Promising microalgal species with high hydrogen production capabilities such as Synechocystis sp., Anabaena variabilis, and Chlamydomonas reinhardtii have been identified. Immobilization techniques like encapsulation in alginate and integration with dark fermentation have led to improved hydrogen yields. Metabolic engineering through modulation of hydrogenase activity and photosynthetic pathways shows potential for enhanced biohydrogen productivity. Considerable progress has been made in developing microalgal systems for biohydrogen. However, challenges around process optimization and scale-up remain. Future work involving metabolic modeling, photobioreactor design, and genetic engineering of electron transfer pathways could help realize the full potential of this renewable technology.

Exploring the potential of 1,8-cineole from cardamom oil against food-borne pathogens: Antibacterial mechanisms and its application in meat preservation.

Food-borne pathogenic bacteria are a major public health concern globally. Traditional control methods using antibiotics have limitations, leading to the exploration of alternative strategies. Essential oils such as cardamom possess antimicrobial properties and have shown efficacy against food-borne pathogenic bacteria. The utilization of essential oils and their bioactive constituents in food preservation is a viable strategy to prolong the shelf-life of food products while ensuring their quality and safety. To the best of our knowledge, there are no studies that have utilized 1,8-cineole (the main active constituent of cardamom essential oil) as a preservative in meat, so this study might be the first to utilize 1,8-cineole as an antibacterial agent in meat preservation. The application of 1,8-cineole had a significant suppressive impact on the growth rate of Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Salmonella Typhimurium in meat samples stored for 7 days at 4 °C. Additionally, the surface color of the meat samples was not negatively impacted by the application of 1,8-cineole. The minimum inhibitory concentration was 12.5-25 mg/ml, and the minimum bactericidal concentration was 25-50.0 mg/ml. The bacterial cell membrane may be the target of cardamom, causing leakage of intracellular proteins, ATP, and DNA. The obtained data in this study may pave a new avenue for using 1,8-cineole as a new perspective for dealing with this problem of food-borne pathogens and food preservation, such as meat.

Decolorization of reactive azo dye using novel halotolerant yeast consortium HYC and proposed degradation pathway.

The presence of high salinity levels in textile wastewater poses a significant obstacle to the process of decolorizing azo dyes. The present study involved the construction of a yeast consortium HYC, which is halotolerant and was recently isolated from wood-feeding termites. The consortium HYC was mainly comprised of Sterigmatomyces halophilus SSA-1575 and Meyerozyma guilliermondii SSA-1547. The developed consortium demonstrated a decolourization efficiency of 96.1% when exposed to a concentration of 50 mg/l of Reactive Black 5 (RB5). The HYC consortium significantly decolorized RB5 up to concentrations of 400 mg/l and in the presence of NaCl up to 50 g/l. The effects of physicochemical factors and the degradation pathway were systematically investigated. The optimal pH, salinity, temperature, and initial dye concentration were 7.0, 3%, 35 °C and 50 mg/l, respectively. The co-carbon source was found to be essential, and the addition of glucose resulted in a 93% decolorization of 50 mg/l RB5. The enzymatic activity of various oxido-reductases was assessed, revealing that NADH-DCIP reductase and azo reductase exhibited greater activity in comparison to other enzymes. UV-Visible (UV-vis) spectrophotometry, Fourier-transform infrared spectroscopy (FTIR), high-performance liquid chromatography (HPLC), and gas chromatography-mass spectrometry (GC-MS) were utilized to identify the metabolites generated during the degradation of RB5. Subsequently, a metabolic pathway was proposed. The confirmation of degradation was established through alterations in the functional groups and modifications in molecular weight. The findings indicate that this halotolerant yeast consortium exhibits promising potential of degrading dye compounds. The results of this study offer significant theoretical basis and crucial perspectives for the implementation of halotolerant yeast consortia in the bioremediation of textile and hypersaline wastewater. This approach is particularly noteworthy as it does not produce aromatic amines.

Can wood-feeding termites solve the environmental bottleneck caused by plastics? A critical state-of-the-art review.

The abundance of synthetic polymers has become an ever-increasing environmental threat in the world. The excessive utilization of plastics leads to the accumulation of such recalcitrant pollutants in the environment. For example, during the COVID-19 pandemic, unprecedented demand for personal protective equipment (PPE) kits, face masks, and gloves made up of single-use items has resulted in the massive generation of plastic biomedical waste. As secondary pollutants, microplastic particles (<5 mm) are derived from pellet loss and degradation of macroplastics. Therefore, urgent intervention is required for the management of these hazardous materials. Physicochemical approaches have been employed to degrade synthetic polymers, but these approaches have limited efficiency and cause the release of hazardous metabolites or by-products into the environment. Therefore, bioremediation is a proper option as it is both cost-efficient and environmentally friendly. On the other hand, plants evolved lignocellulose to be resistant to destruction, whereas insects, such as wood-feeding termites, possess diverse microorganisms in their guts, which confer physiological and ecological benefits to their host. Plastic and lignocellulose polymers share a number of physical and chemical properties, despite their structural and recalcitrance differences. Among these similarities are a hydrophobic nature, a carbon skeleton, and amorphous/crystalline regions. Compared with herbivorous mammals, lignocellulose digestion in termites is accomplished at ordinary temperatures. This unique characteristic has been of great interest for the development of a plastic biodegradation approach by termites and their gut symbionts. Therefore, transferring knowledge from research on lignocellulosic degradation by termites and their gut symbionts to that on synthetic polymers has become a new research hotspot and technological development direction to solve the environmental bottleneck caused by synthetic plastic polymers.

Strategies for efficient management of microplastics to achieve life cycle assessment and circular economy.

The anticipated increase in the influx of plastic waste into aquatic environments has propelled the identification and elimination of plastic waste into the global agenda. The plastics sector generates a significant volume of materials, which, due to their extended durability, accumulate rapidly in natural ecosystems. Consequently, this indiscriminate utilization, along with the deposition of plastic waste (PW) in landfills and inadequate recycling practices, leads to diverse economic, social, and environmental consequences. Microplastics (MPs) are a type of PW that has been fragmented into particles measuring less than 5 mm. These particles have been found in several environments, including the air, soil, freshwater, and ocean ecosystems, where they accumulate in large quantities. In order to gain insight into the ecological risks and resource implications associated with a plastic product, it is strongly advised to conduct life cycle and sustainability analyses. Therefore, this paper examines various strategies aimed at achieving effective management of MP waste in order to develop a conceptual framework for MPs in circular economy and life cycle assessment (LCA). The findings of this study provides a new avenue for future research and contribution to manage MP waste as well as reduce their environmentally hazardous impact.

A critical review on the treatment of dye-containing wastewater: Ecotoxicological and health concerns of textile dyes and possible remediation approaches for environmental safety.

The synthetic dyes used in the textile industry pollute a large amount of water. Textile dyes do not bind tightly to the fabric and are discharged as effluent into the aquatic environment. As a result, the continuous discharge of wastewater from a large number of textile industries without prior treatment has significant negative consequences on the environment and human health. Textile dyes contaminate aquatic habitats and have the potential to be toxic to aquatic organisms, which may enter the food chain. This review will discuss the effects of textile dyes on water bodies, aquatic flora, and human health. Textile dyes degrade the esthetic quality of bodies of water by increasing biochemical and chemical oxygen demand, impairing photosynthesis, inhibiting plant growth, entering the food chain, providing recalcitrance and bioaccumulation, and potentially promoting toxicity, mutagenicity, and carcinogenicity. Therefore, dye-containing wastewater should be effectively treated using eco-friendly technologies to avoid negative effects on the environment, human health, and natural water resources. This review compares the most recent technologies which are commonly used to remove dye from textile wastewater, with a focus on the advantages and drawbacks of these various approaches. This review is expected to spark great interest among the research community who wish to combat the widespread risk of toxic organic pollutants generated by the textile industries.

Streptomyces rochei MS-37 as a Novel Marine Actinobacterium for Green Biosynthesis of Silver Nanoparticles and Their Biomedical Applications.

Periodontitis, as one of the most common diseases on a global scale, is a public health concern. Microbial resistance to currently available antimicrobial agents is becoming a growing issue in periodontal treatment. As a result, it is critical to develop effective and environmentally friendly biomedical approaches to overcome such challenges. The investigation of Streptomyces rochei MS-37's performance may be the first of its kind as a novel marine actinobacterium for the green biosynthesis of silver nanoparticles (SNPs) and potentials as antibacterial, anti-inflammatory, antibiofilm, and antioxidant candidates suppressing membrane-associated dental infections. Streptomyces rochei MS-37, a new marine actinobacterial strain, was used in this study for the biosynthesis of silver nanoparticles for various biomedical applications. Surface plasmon resonance spectroscopy showed a peak at 429 nm for the SNPs. The SNPs were spherical, tiny (average 23.2 nm by TEM, 59.4 nm by DLS), very stable (-26 mV), and contained capping agents. The minimum inhibitory concentrations of the SNPs that showed potential antibacterial action ranged from 8 to 128 µg/mL. Periodontal pathogens were used to perform qualitative evaluations of microbial adhesion and bacterial penetration through guided tissue regeneration membranes. The findings suggested that the presence of the SNPs could aid in the suppression of membrane-associated infection. Furthermore, when the anti-inflammatory action of the SNPs was tested using nitric oxide radical scavenging capacity and protein denaturation inhibition, it was discovered that the SNPs were extremely efficient at scavenging nitric oxide free radicals and had a strong anti-denaturation impact. The SNPs were found to be more cytotoxic to CAL27 than to human peripheral blood mononuclear cells (PBMCs), with IC50 values of 81.16 µg/mL in PBMCs and 34.03 µg/mL in CAL27. This study's findings open a new avenue for using marine actinobacteria for silver nanoparticle biosynthesis, which holds great promise for a variety of biomedical applications, in particular periodontal treatment.

Exploring the therapeutic potential of acetonic plant extracts in the healing of skin wounds infected with multidrug resistant pathogens.

Open wounds are easily susceptible to infection by multi-drug resistant (MDR) pathogens. The emergence of MDR super bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus spp, fungi such as Aspergillus niger and Candida spp, has been identified to significantly increase the incidence rate. Therefore, it is necessary to develop a suitable barrier to prevent infection and enhance wound healing. On the other hand, medicinal plants could represent a significant source of new antimicrobial drugs for combating MDR pathogens. Out of 60 clinical skin burn cases, 51 patients (85%) had polymicrobial infections, while the remaining had monomicrobial infections. Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumonia were identified as the most common bacterial isolates based on morphological and biochemical tests. However, Candida albicans, Candida parasitosis, Candida glabrata, Candida famata, Aspergillus niger, and Exophilia spinifera were the most common fungal isolates found in skin burn cases. MDR classification was reported in 21 of the 39 bacterial isolates and 8 of the 27 fungal isolates. The antimicrobial activity of tested acetonic plant extracts rosemary, henna, and licorice against MDR isolates was compared to the commercial antibiotic agents. Acetonic rosemary extract outperformed henna and licorice extracts in antibacterial activity, while licorice extract outperformed henna and rosemary extracts on antifungal activity. As a result, rosemary and licorice extracts were chosen to prepare a topical cream for further in vivo wound healing and histopathology. Based on the antimicrobial potential of acetonic plant extracts against MDR isolates, BI-41 and FI-17 were chosen for in vivo wound healing. BI-41 stands for the molecularly identified species Pseudomonas aeruginosa SSM-15, while FI-17 stands for molecularly identified species Aspergillus niger SSM-27. In vivo testing showed that both cream formulas had excellent healing properties when administered topically. In vivo histopathological examination revealed that acetonic rosemary and licorice extract could be promising for wound healing, combating MDR pathogens of burn wound infections.

Exploring the potential of Cinnamomum zeylanicum oil against drug resistant Helicobacter pylori-producing cytotoxic genes.

Thirty-one of sixty dyspeptic patients tested positive for Helicobacter pylori colonization in this study, as determined by histopathology and 16S rRNA. The cytotoxin-associated gene A (cagA) and vacuolating cytotoxin A (vacA) genes were found in 67.7 and 93.5% of H. pylori patients, respectively. The cagA gene was found to be associated with 100% of patients with duodenal erosion and ulceration identified via endoscopy examination. In addition, 86.7% of patients with cancerous and precancerous lesions, glandular atrophy, and intestinal metaplasia identified via histopathology examination. The vacA s1m1 mutation was associated with more severe forms of gastric erosion and ulceration, as well as the presence of precancerous and cancerous lesions. Eighteen (64.3%) of the twenty-eight isolates were classified as multi-drug resistant (MDR) or pan-drug resistant (PDR) H. pylori. Due to a resurgence of interest in alternative therapies derived from plants as a result of H. pylori resistance to the majority of commonly used antibiotics, the inhibitory activity of five essential oils extracted from some commonly used medicinal plants was evaluated in vitro against drug-resistant H. pylori clinical isolates. Cinnamomum zeylanicum essential oil demonstrated the highest anti-H. pylori activity when compared to the other essential oils tested. Cinnamaldehyde was the most abundant compound in C. zeylanicum (65.91%). The toxicological evaluation established the safety of C. zeylanicum oil for human use. As a result, C. zeylanicum essential oil may represent a novel antibacterial agent capable of combating drug-resistant H. pylori carrying cytotoxin genes.

Molecular characterization of virulence and drug resistance genes-producing Escherichia coli isolated from chicken meat: Metal oxide nanoparticles as novel antibacterial agents.

Escherichia coli is a major global foodborne pathogen, infecting a wide range of animals and contaminating their meat products. E. coli, can lead to high morbidity and mortality with a huge economic loss especially if foodborne diseases are associated with multidrug resistant (MDR)- and multivirulent-producing pathogens. Due to the increased resistance to common antimicrobials used to treat livestock animals and human infections, the discovery of new and innovative nanomaterials are in high demand. Recently, metal oxides can be considered as effective inorganic agents with antimicrobial features. Hence, this study might be the first to evaluate the efficiency of metal oxide nanoparticles (MO-NPs) as novel antibacterial agents against MDR/multivirulent E. coli pathogens isolated from chicken meat. The occurrence of pathogenic E. coli was determined in fresh warm chicken meat parts (breast, thigh, liver and gizzard). Ninety-one of 132 (69%) chicken meat parts were Escherichia -positive with E. coli as the only species isolated. Out of identified 240 E. coli strains, 72.5% (174/240) were classified as MDR E. coli strains. Fifty-five profile patterns were obtained. From each pattern, one strain was randomly selected for further analysis of virulence and resistance genes. Extracted DNA was assessed for the presence of antibiotic resistance genes (blaIMP-7, blaIMP-25, blaTEM, blaSHV, blaOXA-2, tetA, aadA, and aac(3)-IV) and virulence genes (stx1, stx2, hlyA, eaeA, aggR, eltB, estIb, papA, afa and hlyD). Clustering analyses revealed that 10 E. coli harboring the highest number of virulence and resistance genes were shifted together into one cluster designated as cluster X. The average activities of zinc peroxide nanoparticles (ZnO2-NPs) were higher than that of zinc oxide nanoparticles (ZnO-NPs) and titanium dioxide nanoparticles (TiO2-NPs) by 20% and 29%, respectively. The anti-inflammatory activity of ZnO2-NPs in comparison with aspirin was assessed using membrane stabilization, albumin denaturation, and proteinase inhibition methods. Significant anti-inflammatory activity of ZnO2-NPs was achieved at concentration levels of 500-1000 µg/ml. It seems that MO-NPs are effective alternative agents, since they exhibited a competitive antibacterial capability against MDR/multivirulent-producing E. coli pathogens isolated from chicken meat. Hence, ZnO2-NPs are a promising nanoparticles-based material for controlling foodborne pathogens, thereby valued for food safety applications.

Drug resistance profile and molecular characterization of extended spectrum beta-lactamase (ESßL)-producing Pseudomonas aeruginosa isolated from burn wound infections. Essential oils and their potential for utilization.

OBJECTIVES: Pseudomonas aeruginosa producing extended spectrum ß-lactamase (ESßL) enzyme had the ability for antimicrobial resistance mechanisms and its multidrug-resistant (MDR) phenotype, has been increasingly reported as a major clinical concern worldwide. The aim of this study was to (i) characterize ESßL-producing MDR P. aeruginosa isolated from burn wound infections phenotypically and molecularly, (ii) evaluate the antibacterial activity of some essential oils (EOs) against selected ESßL-producing drug resistant P. aeruginosa and (iii) characterize a promising EO. METHODS: Identification and antibiotic susceptibility tests were performed for all isolates. ESßL production was detected phenotypically by an initial screening test (IST) and a phenotypic confirmatory test (PCT). Additionally, ESßL-producing isolates were also characterized molecularly. The antibacterial activity was detected using a disc diffusion method. Mechanisms of antibacterial action, the fatty acid profile, and functional groups characterization of the promising EO were analyzed using scanning and transmission electron microscopy (SEM & TEM), gas chromatography-mass spectrometry (GC-MS), and Fourier transform infrared (FTIR) spectroscopy, respectively. RESULTS: A total of 50 non duplicated P. aeruginosa isolates from the wound samples of burn patients were identified. Of these, MDR and pan-drug resistance (PDR) showed a high prevalence in 38 (76%) isolates obtained from 10 clusters, while 21 (42%) were identified as ESßL-producing MDR or PDR P. aeruginosa isolates. Phenotypic detection of ESßL production showed that 20% were considered positive ESßL-producing P. aeruginosa using the IST, and were increased to 56% by the PCT. The most prevalent ESßL-encoding gene was blaOXA-2 (60.7%), followed by blaIMP-7 (53.6%) and blaOXA-50 (42.8%). Ginger oil is the most efficient antibacterial agent and its antibacterial action mechanism is attributed to the morphological changes in bacterial cells. The oil characterization revealed that 9,12-Octadecadienoic acid methyl ester is the major fatty acid (50.49%) identified. CONCLUSION: The high incidence of drug-resistance in ESßL-producing P. aeruginosa isolated from burn wounds is alarming. As proven in vitro, EOs may represent promising natural alternatives against ESßL-producing PDR or MDR P. aeruginosa isolates.

Pharmaceutical Potential of a Novel Chitosan Derivative Schiff Base with Special Reference to Antibacterial, Anti-Biofilm, Antioxidant, Anti-Inflammatory, Hemocompatibility and Cytotoxic Activities.

PURPOSE: Chitosan and its derivatives possess several unique properties relevant in the field of pharmaceutics and medicinal chemistry. This study aimed to evaluate the pharmaceutical performance of an innovative chitosan derivative, methyl acrylate chitosan bearing p-nitrobenzaldehyde (MA*CS*pNBA) Schiff base. METHODS: The antibacterial activity of MA*CS*pNBA was tested against multi-drug resistant (MDR) Gram-negative and Gram-positive bacteria using agar-well diffusion method. Anti-biofilm formation was analyzed using a microtitre plate. Antioxidant assays were performed to assess the scavenging activity of MA*CS*pNBA using DPPH, hydrogen peroxide, superoxide together with its reducing power activity. Anti-inflammatory activity was evaluated by albumin denaturation, membrane stabilization, and proteinase inhibition methods. MA*CS*pNBA was tested for its hemolytic efficiency on human erythrocytes. Cytotoxicity of MA*CS*pNBA was evaluated by MTT assay. RESULTS: MA*CS*pNBA showed a significant performance as an antibacterial candidate against MDR bacteria, anti-biofilm, antioxidant and anti-inflammatory biomaterial, evidencing hemocompatibility and no cytotoxicity. It exhibited a significant negative correlation with biofilm formation by the MDR-PA-09 strain. Biological activities were found to be significantly concentration-dependent. CONCLUSIONS: the newly chitosan derivative MA*CS*pNBA showed to be promising for pharmaceutical applications, expanding the treatment ways toward skin burn infections since it allied excellent antibacterial, anti-biofilm, antioxidant, anti-inflammatory, hemocompatibility and absence of cytotoxic activities.

Hypoxia-inducible factor-1α activation improves renal oxygenation and mitochondrial function in early chronic kidney disease.

The pathophysiology of chronic kidney disease (CKD) is driven by alterations in surviving nephrons to sustain renal function with ongoing nephron loss. Oxygen supply-demand mismatch, due to hemodynamic adaptations, with resultant hypoxia, plays an important role in the pathophysiology in early CKD. We sought to investigate the underlying mechanisms of this mismatch. We utilized the subtotal nephrectomy (STN) model of CKD to investigate the alterations in renal oxygenation linked to sodium (Na) transport and mitochondrial function in the surviving nephrons. Oxygen delivery was significantly reduced in STN kidneys because of lower renal blood flow. Fractional oxygen extraction was significantly higher in STN. Tubular Na reabsorption was significantly lower per mole of oxygen consumed in STN. We hypothesized that decreased mitochondrial bioenergetic capacity may account for this and uncovered significant mitochondrial dysfunction in the early STN kidney: higher oxidative metabolism without an attendant increase in ATP levels, elevated superoxide levels, and alterations in mitochondrial morphology. We further investigated the effect of activation of hypoxia-inducible factor-1α (HIF-1α), a master regulator of cellular hypoxia response. We observed significant improvement in renal blood flow, glomerular filtration rate, and tubular Na reabsorption per mole of oxygen consumed with HIF-1α activation. Importantly, HIF-1α activation significantly lowered mitochondrial oxygen consumption and superoxide production and increased mitochondrial volume density. In conclusion, we report significant impairment of renal oxygenation and mitochondrial function at the early stages of CKD and demonstrate the beneficial role of HIF-1α activation on renal function and metabolism.

The diabetic brain and cognition.

The prevalence of both Alzheimer's disease (AD) and vascular dementia (VaD) is increasing with the aging of the population. Studies from the last several years have shown that people with diabetes have an increased risk for dementia and cognitive impairment. Therefore, the authors of this consensus review tried to elaborate on the role of diabetes, especially diabetes type 2 (T2DM) in both AD and VaD. Based on the clinical and experimental work of scientists from 18 countries participating in the International Congress on Vascular Disorders and on literature search using PUBMED, it can be concluded that T2DM is a risk factor for both, AD and VaD, based on a pathology of glucose utilization. This pathology is the consequence of a disturbance of insulin-related mechanisms leading to brain insulin resistance. Although the underlying pathological mechanisms for AD and VaD are different in many aspects, the contribution of T2DM and insulin resistant brain state (IRBS) to cerebrovascular disturbances in both disorders cannot be neglected. Therefore, early diagnosis of metabolic parameters including those relevant for T2DM is required. Moreover, it is possible that therapeutic options utilized today for diabetes treatment may also have an effect on the risk for dementia. T2DM/IRBS contribute to pathological processes in AD and VaD.

Physiological and pathophysiological reactive oxygen species as probed by EPR spectroscopy: the underutilized research window on muscle ageing.

Reactive oxygen and nitrogen species (ROS and RNS) play crucial roles in triggering, mediating and regulating physiological and pathophysiological signal transduction pathways within the cell. Within the cell, ROS efflux is firmly controlled both spatially and temporally, making the study of ROS dynamics a challenging task. Different approaches have been developed for ROS assessment; however, many of these assays are not capable of direct identification or determination of subcellular localization of different ROS. Here we highlight electron paramagnetic resonance (EPR) spectroscopy as a powerful technique that is uniquely capable of addressing questions on ROS dynamics in different biological specimens and cellular compartments. Due to their critical importance in muscle functions and dysfunction, we discuss in some detail spin trapping of various ROS and focus on EPR detection of nitric oxide before highlighting how EPR can be utilized to probe biophysical characteristics of the environment surrounding a given stable radical. Despite the demonstrated ability of EPR spectroscopy to provide unique information on the identity, quantity, dynamics and environment of radical species, its applications in the field of muscle physiology, fatiguing and ageing are disproportionately infrequent. While reviewing the limited examples of successful EPR applications in muscle biology we conclude that the field would greatly benefit from more studies exploring ROS sources and kinetics by spin trapping, protein dynamics by site-directed spin labelling, and membrane dynamics and global redox changes by spin probing EPR approaches.

Pyocyanin as anti-tyrosinase and anti tinea corporis: A novel treatment study.

OBJECTIVE: The aim of this study was to evaluate the efficiency of pyocyanin pigment as a novel compound active against tyrosinase with its depigmentation efficiency for combating Trichophyton rubrum which could be a major causative agent of tinea corporis. METHODS: Fifty swabs of fungal tinea corporis infections were collected and identified. Five MDRPA isolates were tested for their levels of pyocyanin production. The purified extracted pyocyanin was characterized by UV spectrum and FT-IR analysis. Pyocyanin activity against tyrosinase was determined by dopachrome micro-plate. In addition, the antidermatophytic activity of pyocyanin against T. rubrum was detected by radial growth technique. In vivo novel trial was conducted to evaluate the efficiency and safety of pyocyanin as an alternative natural therapeutic compound against T. rubrum causing tinea corporis. RESULTS: Purified pyocyanin showed highly significant inhibitory activity against tyrosinase and T. rubrum. In vivo topical treatments with pyocyanin ointment revealed the efficiency of pyocyanin (MIC 2000 µg/ml) to cure tinea corporis compared to fluconazole, which showed a partial curing at a higher concentration (MIC 3500 µg/ml) after two weeks of treatment. In addition, the results revealed complete healing and disappear of hyperpigmentation by testing the safety of pyocyanin ointment and its histopathological efficiency in the skin treatment without any significant toxic effect. CONCLUSION: Pyocyanin pigment could be a promising anti-tyrosinase and a new active compound against T. rubrum, which could be a major causative agent of tinea corporis. In fact, if pyocyanin secondary metabolite is going to be used in practical medication, it will support the continuous demand of novel antimycotic natural agents against troublesome fungal infections.