A novel antimicrobial therapy for the control of Aeromonas hydrophila infection in aquaculture using marine polysaccharide coated gold nanoparticle

Antimicrobial activity of probiotic bacteria-mediated cadmium oxide nanoparticles against fish pathogens

The current research was designed to investigate the antibacterial activity of probiotic bacteria mediated cadmium oxide nanoparticles (CdO NPs) on common fish pathogenic bacteria like Serratia marcescens, Aeromonas hydrophila, Vibrio harveyi, and V. parahaemolyticus. CdO NPs were synthesized using probiotic bacteria as follows: Lactobacillus species with different precursor of cadmium sulfate concentrations (5, 10, and 20 mM). The average crystalline sizes of the CdO NPs were determined based on the XRD patterns using the Debye-Scherrer equation for different precursor concentrations. Specifically, sizes of 40, 48, and 67 nm were found at concentrations of 5, 10, and 20 mM, respectively. The antibacterial efficacy of CdO NPs was estimated using a well diffusion assay, which demonstrated the best efficacy of 20 mM CdO NPs against all pathogens. AFM analysis of nanoparticle-treated and untreated biofilms was performed to further validate the antibacterial effect. Antibacterial activity of CdO nanoparticles synthesized at varying concentrations (5, 10, and 20 mM) against fish pathogens (S. marcescens, A. hydrophila, V. harveyi, and V. parahaemolyticus). The results indicated the highest inhibitory effect of 20 mM CdO NPs across all concentrations (30, 60, and 90 μg/mL), demonstrating significant inhibition against S. marcescens. These findings will contribute to the development of novel strategies for combating aquatic diseases and advancing aquaculture health management practices.

Antimicrobial, antibiofilm, and antivirulence properties of Eisenia bicyclis-extracts and Eisenia bicyclis-gold nanoparticles towards microbial pathogens

Nanomaterials derived from seaweed have developed as an alternative option for fighting infections caused by biofilm-forming microbial pathogens. This research aimed to discover potential seaweed-derived nanomaterials with antimicrobial and antibiofilm action against bacterial and fungal pathogens. Among seven algal species, the extract from Eisenia bicyclis inhibited biofilms of Klebsiella pneumoniae, Staphylococcus aureus, and Listeria monocytogenes most effectively at sub-MIC levels. As a result, in the present study, E. bicyclis was chosen as a prospective seaweed for producing E. bicyclis-gold nanoparticles (EB-AuNPs). Furthermore, the mass spectra of E. bicyclis reveal the presence of a number of potentially beneficial chemicals. The polyhedral shape of the synthesized EB-AuNP with a size value of 154.74 ± 33.46 nm was extensively described. The lowest inhibitory concentration of EB-AuNPs against bacterial pathogens (e.g., L.monocytogenes, S. aureus, Pseudomonas aeruginosa, and K. pneumoniae) and fungal pathogens (Candida albicans) ranges from 512 to >2048 μg/mL. Sub-MIC of EB-AuNPs reduces biofilm formation in P. aeruginosa, K. pneumoniae, L. monocytogenes, and S. aureus by 57.22 %, 58.60 %, 33.80 %, and 91.13 %, respectively. EB-AuNPs eliminate the mature biofilm of K. pneumoniae at > MIC, MIC, and sub-MIC concentrations. Furthermore, EB-AuNPs at the sub-MIC level suppress key virulence factors generated by P. aeruginosa, including motility, protease activity, pyoverdine, and pyocyanin, whereas it also suppresses the production of staphyloxanthin virulence factor from S. aureus. The current research reveals that seaweed extracts and a biocompatible seaweed-AuNP have substantial antibacterial, antibiofilm, and antivirulence actions against bacterial and fungal pathogens.

Blood cell alterations in Colossoma macropomum juveniles caused by silver nanoparticles

This study evaluated the median lethal concentration of silver nanoparticles and their effects in fish tambaqui Colossoma macropomum. Therefore, an acute toxicity assay was carried out in completely randomized design evaluating six different concentrations of silver nanoparticles on blood parameters of tambaqui. The silver nanoparticles were produced by chemical reduction with polyvinyl alcohol (AgNP-PVA). The lethal concentration 50% (LC50) was estimated using probit regression. The blood was collected, analyzed and the data were submitted to T-test (dying x surviving fish) and Tukey test (surviving fish). An increase in glucose, hematocrit, total plasma protein, hemoglobin, erythrocytes, leukocytes, monocytes, and neutrophils as well as reduced MCV (mean corpuscular volume) in dying fish compared to surviving fish were observed. Survived fish exposed to 187.5 µg/L showed an increase in hematocrit, MCV, and MCH and a reduction in erythrocytes, total numbers of leukocyte, thrombocyte, lymphocyte, and neutrophil. The fish exposed to concentrations below 125 µg/L, had returned the blood parameter to baselines compared to control. The estimated LC50 was 165.09 µg/L and was classified as highly toxic for the fish tambaqui. In higher concentrations, it causes an acute respiratory toxicity, but in concentrations below 125 µg/L, the fish can adapt to the stressing agent.

Insights into the mechanisms and key factors influencing biofilm formation by Aeromonas hydrophila in the food industry: A comprehensive review and bibliometric analysis

Biofilm formation by Aeromonas hydrophila in the food industry poses significant challenges to food safety and quality. Therefore, this comprehensive review aimed to provide insights into the mechanisms and key factors influencing A. hydrophila biofilm formation. It explores the molecular processes involved in initial attachment, microcolony formation, and biofilm maturation; moreover, it concurrently examines the impact of intrinsic factors, including quorum sensing, cyclic-di-GMP, the efflux pump, and antibiotic resistance, as well as environmental conditions, such as temperature, nutrient availability, and osmotic pressure, on biofilm architecture and resilience. Furthermore, the article highlights the potential of bibliometric analysis as a promising method for conceptualizing the research landscape of and identifying knowledge gaps in A. hydrophila biofilm research. The findings underscore the requirement for focused interventions that prevent biofilm development and raise food sector safety. The consolidation of current information and incorporation of bibliometric analysis enhances existing understanding of A. hydrophila biofilm formation and offers insights for future research and control strategies within a food industry context.

Nanovaccines to Combat Aeromonas hydrophila Infections in Warm-Water Aquaculture: Opportunities and Challenges

The application of nanotechnology in aquaculture for developing efficient vaccines has shown great potential in recent years. Nanovaccination, which involves encapsulating antigens of fish pathogens in various polymeric materials and nanoparticles, can afford protection to the antigens and a sustained release of the molecule. Oral administration of nanoparticles would be a convenient and cost-effective method for delivering vaccines in aquaculture while eliminating the need for stressful, labour-intensive injectables. The small size of nanoparticles allows them to overcome the degradative digestive enzymes and help deliver antigens to the target site of the fish more effectively. This targeted-delivery approach would help trigger cellular and humoral immune responses more efficiently, thereby enhancing the protective efficacy of vaccines. This is particularly relevant for combating diseases caused by pathogens like Aeromonas hydrophila, a major fish pathogen responsible for significant morbidity and mortality in the aquaculture sector. While the use of nanoparticle-based vaccines in aquaculture has shown promise, concerns exist about the potential toxicity associated with certain types of nanoparticles. Some nanoparticles have been found to exhibit varying degrees of toxicity, and their safety profiles need to be thoroughly assessed before widespread application. The introduction of nanovaccines has opened new vistas for improving aquaculture healthcare, but must be evaluated for potential toxicity before aquaculture applications. Details of nanovaccines and their mode of action, with a focus on protecting fish from infections and outbreaks caused by the ubiquitous opportunistic pathogen A. hydrophila, are reviewed here.

Management and Mitigation of Vibriosis in Aquaculture: Nanoparticles as Promising Alternatives

Vibriosis is one of the most common diseases in marine aquaculture, caused by bacteria belonging to the genus Vibrio, that has been affecting many species of economically significant aquatic organisms around the world. The prevention of vibriosis in aquaculture is difficult, and the various treatments for vibriosis have their limitations. Therefore, there is an imperative need to find new alternatives. This review is based on the studies on vibriosis, specifically on the various treatments and their limitations, as well as the application of nanoparticles in aquaculture. One of the promising nanoparticles is graphene oxide (GO), which has been used in various applications, particularly in biological applications such as biosensors, drug delivery, and potential treatment for infectious diseases. GO has been shown to have anti-bacterial properties against both Gram-positive and Gram-negative bacteria, but no research has been published that emphasizes its impact on Vibrio spp. The review aims to explore the potential use of GO for treatment against vibriosis.

The Widespread Use of Nanomaterials: The Effects on the Function and Diversity of Environmental Microbial Communities

In recent years, as an emerging material, nanomaterials have rapidly expanded from laboratories to large-scale industrial productions. Along with people's productive activities, these nanomaterials can enter the natural environment of soil, water and atmosphere through various ways. At present, a large number of reports have proved that nanomaterials have certain toxic effects on bacteria, algae, plants, invertebrates, mammalian cell lines and mammals in these environments, but people still know little about the ecotoxicology of nanomaterials. Most relevant studies focus on the responses of model strains to nanomaterials in pure culture conditions, but these results do not fully represent the response of microbial communities to nanomaterials in natural environments. Over the years, the effect of nanomaterials infiltrated into the natural environment on the microbial communities has become a popular topic in the field of nano-ecological environment research. It was found that under different environmental conditions, nanomaterials have various effects on the microbial communities. The medium; the coexisting pollutants in the environment and the structure, particle size and surface modification of nanomaterials may cause changes in the structure and function of microbial communities. This paper systematically summarizes the impacts of different nanomaterials on microbial communities in various environments, which can provide a reference for us to evaluate the impacts of nanomaterials released into the environment on the microecology and has certain guiding significance for strengthening the emission control of nanomaterials pollutants.

Antibiotic resistance in aquaculture and aquatic organisms: a review of current nanotechnology applications for sustainable management

Aquaculture has emerged as one of the world's fastest-growing food industries in recent years, helping food security and boosting global economic status. The indiscriminate disposal of untreated or improperly managed waste and effluents from different sources including production plants, food processing sectors, and healthcare sectors release various contaminants such as bioactive compounds and unmetabolized antibiotics, and antibiotic-resistant organisms into the environment. These emerging contaminants (ECs), especially antibiotics, have the potential to pollute the environment, particularly the aquatic ecosystem due to their widespread use in aquaculture, leading to various toxicological effects on aquatic organisms as well as long-term persistence in the environment. However, various forms of nanotechnology-based technologies are now being explored to assist other remediation technologies to boost productivity, efficiency, and sustainability. In this review, we critically highlighted several ecofriendly nanotechnological methods including nanodrug and vaccine delivery, nanoformulations, and nanosensor for their antimicrobial effects in aquaculture and aquatic organisms, potential public health risks associated with nanoparticles, and their mitigation measures for sustainable management.

Fucoidan-based nanoparticles: Preparations and applications

Nanoparticle-based therapy has gained much attention in the pharmaceutical industry. Fucoidan is a sulfated polysaccharide naturally derived from marine brown algae and is widely used for medical applications. We explore preparation of fucoidan-based nanoparticles and their biomedical applications in the current review. The fucoidan-based nanoparticles have been synthesized using microwave, emulsion, solvent evaporation, green synthesis, polyelectrolyte self-assembly, precipitation, and ultrasonication methods. The synthesized nanoparticles have particle sizes ranging from 100 to 400 nm. Therefore, fucoidan-based nanoparticles have a variety of potential therapeutic applications, including drug delivery, cancer therapies, tissue engineering, antimicrobial applications, magnetic resonance imaging contrast, and atherothrombosis imaging. For example, fucoidan nanoparticles have been used to deliver curcumin, dextran, gentamicin, epigallocatechin gallate, and cisplatin for cancer therapies. Furthermore, fucoidan nanoparticles coupled with metal nanoparticles have been used to target and recognize clinical conditions for diagnostic purposes. Hence, fucoidan-based nanoparticles have been helpful for biomedical applications.

Green Metallic Nanoparticles: Biosynthesis to Applications

Current advancements in nanotechnology and nanoscience have resulted in new nanomaterials, which may pose health and environmental risks. Furthermore, several researchers are working to optimize ecologically friendly procedures for creating metal and metal oxide nanoparticles. The primary goal is to decrease the adverse effects of synthetic processes, their accompanying chemicals, and the resulting complexes. Utilizing various biomaterials for nanoparticle preparation is a beneficial approach in green nanotechnology. Furthermore, using the biological qualities of nature through a variety of activities is an excellent way to achieve this goal. Algae, plants, bacteria, and fungus have been employed to make energy-efficient, low-cost, and nontoxic metallic nanoparticles in the last few decades. Despite the environmental advantages of using green chemistry-based biological synthesis over traditional methods as discussed in this article, there are some unresolved issues such as particle size and shape consistency, reproducibility of the synthesis process, and understanding of the mechanisms involved in producing metallic nanoparticles via biological entities. Consequently, there is a need for further research to analyze and comprehend the real biological synthesis-dependent processes. This is currently an untapped hot research topic that required more investment to properly leverage the green manufacturing of metallic nanoparticles through living entities. The review covers such green methods of synthesizing nanoparticles and their utilization in the scientific world.

Marine organisms: Pioneer natural sources of polysaccharides/proteins for green synthesis of nanoparticles and their potential applications

Current innovations in the marine bionanotechnology arena are supporting and stimulating developments in other fields, including nanomedicine, pharmaceuticals, sensors, environmental trends, food, and agriculture aspects. Many oceanic creatures, particularly algae, plants, bacteria, yeast, fungi, cyanobacteria, actinomyces, invertebrates, animals and sponges can survive under extreme circumstances. They can biogenerate a broad spectrum of phytochemicals/metabolites, including proteins, peptides, alkaloids, flavonoids, polyphenols, carbohydrate polymers, polysaccharides, sulfated polysaccharides, polysaccharide-protein complexes such as carrageenan, fucoidanase, fucoidan, carboxymethyl cellulose, poly-γ-glutamic acid, sugar residues with proteins, melanin, haemocyanin, etc). These products exhibit exclusive advantages that offer pioneering roles in the eco-friendly fabrication of several nanoparticles (NPs) i.e., Ag, Au, Ru, Fe₂O₃, Cobalt (III) Oxide (Co₂O₃), ZnO and Ag@AgCl within a single phase. Importantly, marine organisms can biosynthesize NPs in two modes, namely extracellular and intracellular. Biosynthesized NPs can be characterized using various methodologies among them, ultraviolet-visible spectroscopy, fourier transform infrared spectroscopy, transmission electron microscopy, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Taken together, this review focuses on the green synthesis of metallic, metallic oxides and nonmetallic NPs utilizing extracts/derivatives from marine organisms based on eco-friendly green biogenic procedures. Moreover, significant attention is given to the medicinal and industrial importance of such marine organisms mediated NPs.

Preparation of Amomum longiligulare polysaccharides 1- PLGA nanoparticle and its immune enhancement ability on RAW264.7 cells

Amomum longiligulare polysaccharides 1 (ALP1) was a glucosan that possessed an immune enhancement ability. However, disadvantages including short biological half-life hindered the application of ALP1. To solve these shortcomings, ALP1 was successfully prepared to nanoparticles (ALPP) with poly (lactic-co-glycolic acid) in the present study. And the optimal preparation conditions were developed by using the response surface method with a Box-Behnken design. The results showed that the encapsulation efficiency of ALPP reached a high level (79.88%) when the volume ratio of the water phase to the organic phase was 1:7, the volume ratio of the primary emulsion to the external water phase was 1:7, and the concentration of F68 was 0.7%. ALPP showed a controlled and sustained release. Meanwhile, the scanning electron microscope results showed that ALPP was a kind of nanoparticles with a diameter of 389.77 nm. In addition, the activating effect of ALPP on macrophages was studied. The results indicated that ALPP showed a better activity on promoting the RAW264.7 cells' activities and polarizing RAW264.7 cells into both M1 type and M2 type macrophages, compared to ALP1.

Current Designs and Developments of Fucoidan-based Formulations for Cancer Therapy

BACKGROUND

Natural nanostructure materials have been involved in antitumor drug delivery systems due to their biocompatibility, biodegradation, and bioactive properties.

METHODS

These materials have contributed to advanced drug delivery systems in the roles of both bioactive compounds and delivery nanocarriers. Fucoidan, a valuable ocean material used in drug delivery systems, has been exploited in research on cancer and a variety of other diseases.

RESULTS

Although the uniqueness, structure, properties, and health benefits of fucoidan have been mentioned in various prominent reviews, current developments and designs of fucoidan-based formulations still need to be assessed to further develop an effective anticancer therapy. In this review, current important formulations using fucoidan as a functional material and as an anticancer agent will be discussed. This article will also provide a brief principle of the methods that incorporate functional nanostructure materials in formulations exploiting fucoidan.

CONCLUSION

Current research and future perspectives on the use of fucoidan in anticancer therapy will advance innovative and important products for clinical uses.

Review on marine carbohydrate-based gold nanoparticles represented by alginate and chitosan for biomedical application

Gold nanoparticles (AuNPs) have been attracted considerable attention in cancer therapy, drug delivery and other applications due to their unique physical, chemical, and optical properties. Marine carbohydrates are important biological macromolecules that widely exist in marine algae and animals, such as alginate, carrageenan, porphyran, fucoidan, ulvan, agarose, and chitosan. Their excellent properties, such as biocompatibility, biodegradability and no irritation, make them widely used in biomedicine and nanomaterials fields. More importantly, they can be easily modified by functional groups, such as sulfation, acetylation, and carboxylation, to further extend their applications. The marine carbohydrates functionalized AuNPs can increase their biocompatibility and targeting in a green preparation method. Here, we review recent advances on marine carbohydrate-based AuNPs for cancer therapy, imaging, drug delivery and other biomedical fields. The topics of selective surface modification in different carbohydrates and further biomedical applications of AuNPs are also discussed.

Low molecular weight fucoidan alleviates diabetic nephropathy by binding fibronectin and inhibiting ECM-receptor interaction in human renal mesangial cells

Diabetic nephropathy (DN) is the most common cause of end-stage renal disease (ESRD). Currently, approximately 20-40% of individuals with diabetes are diagnosed with DN. Mesangial cells (MCs) are critical for maintaining and regulating glomerular filtration, and the abnormal proliferation of MCs causes the accumulation of mesangial extracellular matrix (ECM), further promoting glomerular dysfunction and renal diseases. Low molecular weight fucoidan (LMWF) extracted from Saccharina japonica could alleviate DN, but the mechanism was not analysed. Based on the ability of LMWF to ameliorate the human renal mesangial cell (HRMC) injury caused by advanced glycation end products (AGEs), we identified fibronectin (FN) as the most obviously impacted protein in the ECM-receptor interaction by proteomic analysis. The co-localization of LMWF and FN indicated direct interaction between them, and surface plasmon resonance (SPR) analysis confirmed the specific binding with a K_D of 453.7 μmol L^-1. Positively charged protamine sulfate (PS) promoted the combination of LMWF and HRMCs and further enhanced the effect of LMWF on HRMC injury. Our results indicated that LMWF alleviates the HRMC injury caused by AGEs via binding FN and inhibiting the ECM-receptor interaction pathway. These results provide a foundation for the in-depth analysis of the mechanism of polysaccharide functions.

Seasonal variations in antibiotic resistance genes in estuarine sediments and the driving mechanisms

Estuary sediments are chemically contaminated by adjacent coastal industrial cities, but the impact of organic pollutants on antibiotic resistance genes (ARGs) in estuarine sediments is unknown. We comprehensively analyzed the complex interactions between chemical pollutants (heavy metals and organic pollutants), mobile genetic elements (MGEs), and ARGs in estuarine sediments during various seasons. The results indicate that under the effects of the chemically polluted river water, the number of different estuarine sediment ARGs increased by 76.9%-92.3% in summer and 5.9%-35.3% in winter, and the abundance of these ARGs increased by 29-5195 times in summer and 48-239 times in winter. The abundance of sediment ARGs in distinct estuaries showed different seasonal trends. Seasonal changes had a greater impact on the abundance of estuarine sediment ARGs than on their diversity. The diversity of estuarine sediment ARGs was positively correlated with the chemical pollution levels. Furthermore, chemical pollution was positively correlated with MGEs, and MGEs were correlated with ARG abundance. These results indicate that ARGs are enriched in bacteria via horizontal gene transfer triggered by chemical pollution, promoting multi-antibiotic resistance in estuarine sediment bacteria. These findings have implications for our understanding of the distribution and propagation of ARGs in chemically polluted estuarine sediments.

Microbial community successional patterns in offshore sediments impacted by chemical pollution from Taizhou and Xiamen Cities in China

An Illumina-based next-generation sequencing was employed to characterise the sediment microbiome adjacent to coastal industrial and tourist cities, Taizhou and Xiamen, in China, and their associations with chemical pollution were explored. The results indicated that chemical pollution of sediments from Taizhou was higher than that from Xiamen. The number of sediment bacterial genera was negatively (Taizhou) or positively (Xiamen) correlated with offshore distance, owing to shifts in the primary and secondary status of organic matter and chemical pollutants for the promotion or inhibition of the sediment microbiome. The total number of the operational taxonomic units (OTUs) in sediments from Taizhou was larger than from Xiamen, while the number of core OTUs was smaller indicating that Taizhou had more impact on core microbes in sediments than Xiamen. This study suggests that chemical pollutants and organic matter result in different co-regulation of the off-shore sediment microbiome of coastal industrial and tourist cities.

Biopolymer K-carrageenan wrapped ZnO nanoparticles as drug delivery vehicles for anti MRSA therapy

Kappa-Carrageenan wrapped ZnO nanoparticles (KC-ZnO NPs) was synthesized, physico-chemically characterized and evaluated their biocompatibility and antimicrobial therapy against MRSA. XRD showed the highly crystalline and hexagonal phase structure of ZnO NPs. FETEM confirmed the spherical and hexagonal shaped particle with the mean size of 97.03 ± 9.05 nm. The synthesized KC-ZnO NPs exhibited significant antibacterial activity against MRSA. The biofilm growth of MRSA was greatly inhibited at 100 μg/ml as observed through live and dead cell assay. KC-ZnO NPs have shown invitro anti-inflammatory activity (82%) at 500 μg/ml. KC-ZnO NPs was non-toxic to NIH3T3 mouse embryonic fibroblasts cell lines. Further, no apoptotic and necrotic mediated death in NIH3T3 mouse embryonic fibroblasts cells were noticed by flow cytometric analysis. KC-ZnO NPs have good biocompatibility as recorded by the least hemolysis percentage (<3%) up to 100 μg/ml, which is much lesser than the acceptable limit. In addition, ecosafety analysis has shown that KC-ZnO NPs and kappa karrageenan (0-500 μg/ml) caused no mortality of A. salina after 48 h. However, bare zinc acetate has shown 35% mortality of A. salina after 48 h. The results conclude that KC-ZnO NPs could be a novel antibacterial therapy for the treatment of MRSA associated infectious.

Polyethylenimine-coated PLGA nanoparticles-encapsulated Angelica sinensis polysaccharide as an adjuvant to enhance immune responses

Nanoparticle delivery systems have been widely investigated as new vaccines strategy to enhance the immune responses to antigens against infectious diseases. The positively charged nanoparticles could efficiently improve the immune responses due to targeting and activating the antigen-presenting cells. In this study, the immunopotentiator Angelica sinensis polysaccharide (ASP) was encapsulated into Poly (lactic-co-glycolic acid) (PLGA) nanoparticles, and the polyethylenimine, one of the cationic polymers, was used to coat nanoparticles to develop a new nanoparticle delivery system (ASP-PLGA-PEI) with positively charged. The ASP-PLGA-PEI nanoparticles significantly activated macrophages, and promoted the expression of the MHCII and CD86 and the production of IL-1β and IL-12p70 cytokines of macrophages. Furthermore, the antigen adsorbed on the surface of the ASP-PLGA-PEI nanoparticles enhanced the antigen uptake by macrophages. Moreover, the mice immunized with PCV2 antigen adsorbed ASP-PLGA-PEI nanoparticles significantly enhanced PCV2-specific IgG immune response and the levels of cytokines, induced a mixed Th1/Th2 immune response with Th1 bias compared with other groups. These findings demonstrate that the positively charged nanoparticles (ASP-PLGA-PEI) have the potential to serve as an effective vaccine delivery and adjuvant system to induce vigorous and long-term immune responses.