The aim of this study was to produce fungal chitosan from a potential fungus using a cost-effective substrate (sugar beet molasses) and optimize the growth conditions using Taguchi L9 orthogonal array (OA). The obtained fungal chitinous chitosan (FC) was then used for the microencapsulation of crocin. Optimal conditions were found as 120 mL/L molasses, initial pH at 6 and 5 g/L magnesium sulphate. The dried biomass was weighed as 22.7 g/L, while 8.1 g/L alkali insoluble material (AIM), 5.3 g/L FC and 2.7 g/L native chitosan (NC) were obtained. Deacetylation degree (DD) of the obtained chitosan was calculated as 80.27 and 78.81

Biofilms are implicated in most chronic infections and exhibit up to 1000-fold higher antibiotic resistance than planktonic cells, creating an urgent need for new antibiofilm agents. Here, we characterized GK-11, an 11-amino acid derivative of pleurocidin. Although GK-11 showed limited antimicrobial activity (MIC: 64 µg/mL for Staphylococcus aureus and 256 µg/mL for Pseudomonas aeruginosa), it demonstrated potent antibiofilm effects at sub-MIC levels (MBIC: 32 µg/mL and 16 µg/mL, respectively). Microscopy and SEM confirmed disruption of biofilm structure, while qRT-PCR revealed downregulation of key virulence genes. GK-11 was non-toxic to Caenorhabditis elegans and maintained > 80

Antioxidants are organic molecules that scavenge reactive oxygen species (ROS) and reactive nitrogen species (RNS), thereby maintaining cellular redox balance in living organisms. The human body synthesizes endogenous antioxidants, whereas humans obtain exogenous antioxidants from other organisms such as plants, animals, fungi, and bacteria. This review primarily focuses on the antioxidant potential of natural metabolites and extracts from five major bacterial phyla, including the well-studied Actinobacteria and Cyanobacteria, as well as less-studied Bacteroides, Firmicutes, and Proteobacteria. The literature survey revealed that the metabolites and the extracts with antioxidant activity can be obtained from bacterial cells and their culture supernatants. The metabolites with antioxidant activity include pigments, phycobiliproteins, polysaccharides, mycosporins-like amino acids, peptides, phenolic compounds, and alkaloids. Both metabolites and extracts demonstrate in vitro antioxidant capacity through radical-scavenging, metal-reducing, and metal-chelating activity assays. In in vivo models, they can scavenge ROS and RNS directly and/or indirectly eliminate them by enhancing the activities of antioxidant enzymes, such as catalase, superoxide dismutase, and glutathione peroxidase. Due to their antioxidant activities, they may find applications in the cosmetic industry as anti-aging agents for the skin and in medicine as drugs or supplements for combating oxidative stress-related disorders, such as neurodegenerative diseases and diabetes. The literature survey also elucidated that some metabolites and extracts with antioxidant activity also exhibited strong antimicrobial properties. Therefore, we consider that they may have future applications in the treatment of infectious diseases, the preparation of pathogen-free healthy foods, and the extension of food shelf life.

In recent years, the discovery of new antimicrobial agents has become necessary because of the increase in antibiotic resistance, the development of herbicides and fungicides resistance. Among the antimicrobial agents, antimicrobial peptides (AMPs) stand out due to their stable structure. In this study, the aim was to identify a thermostable AMP from the seeds of M. sativa "Sazova" cultivar and to analyze gene expression during germination. Antimicrobial tests were performed for the seed peptides after heat treatment (85 °C for 10 min), revealing antimicrobial effects against S. aureus, E. coli, and C. albicans. Subsequently, the peptide band corresponding to the inhibition zone was identified as M. sativa Defensin 2.1 (MsDef2.1, MW: 5.2048 kDa). The gene expression analysis of MsDef2.1 in Sazova cultivar showed that the gene was expressed different plant organs, and the expression was decreased over time. As a result of the gene analysis of two cultivars (Sazova and LegenDairy) it was found that there are 5 base differences in the coding sequence and 3 amino acid differences between the sequences of MsDef2.1 isoforms from the LegenDairy and Sazova cultivars. The physiochemical properties, secondary, and tertiary structure of the Sazova Defensin 2.1 were predicted by using bioinformatic tools. Due to the amino acid substitutions in γ-core structures, the antimicrobial activity of the isoforms is expected to differ from each other. These findings demonstrated that the defensin MsDef2.1 can differ in M. sativa cultivars in respect of the gene and amino acid sequences and has a potential for future applications.

This study aimed to assess the in vitro probiotic and antioxidant potential of lactic acid bacteria (LAB) isolated from different white cheeses, also known as “Beyaz Peynir” in Turkey. A total of 58 bacterial strains were isolated from 11 different white cheeses obtained from small-scale dairies. According to some preselection criteria (having the distinctive features of LAB, exhibiting non-haemolytic property, and resisting the simulated gastrointestinal conditions such as low pH, pepsin, pancreatin and bile salt tolerance), four (ED13, ED20, ED25 and ED36) out of 58 isolates were selected for the subsequent experiments. Among the four isolates, ED25 exhibited the maximum lactase production and cholesterol removal potential, the highest biological activity (antimicrobial and antioxidant activity) and the lowest antibiotic resistance. In addition, the second highest B12-producing capacity were measured for ED25. The isolate ED25 was found to possess antimicrobial effectiveness against all tested microorganisms (S. aureus, E. coli, S. Typhimurium, L. monocytogenes and C. albicans) according to the agar well diffusion method. In vitro antioxidant activity assay demonstrated that the culture supernatant of the ED25 had the ability to scavenge DPPH (49

Background Hydrophobins have great potential in many biotechnological applications due to changing surface characteristics. In recent years, although there has been a significant increase in the biotechnological applications of hydrophobins, industrial production has still not been achieved due to yield problems. Therefore, more studies are needed on the recombinant production of hydrophobins. In this work, the recombinant production of class I hydrophobin DewA from Aspergillus nidulans, which is determined to have high contact angle in the literature, was aimed. As a result, DewA protein was recombinantly produced using P. pastoris X-33 strain under AOX1 promoter by transferring into pPICZα-A vector. Results The optimal culture condition for DewA expression was obtained at 1% methanol concentration as 77 mg/L in 96 hour. Recombinant DewA has been proven to change the surface characteristics on the teflon and glass surfaces. Then, the surface stability of the protein was evaluated by applying hot SDS and UV to these surfaces. The surface-coated DewA was resistant to hot SDS application on both glass and teflon surfaces; in the UV application, it was understood that while the protein was degraded by UV exposure on glass surfaces, it preserved its structure on teflon surfaces. Conclusions In the study, the DewA protein of A.nidulans was cloned into the pPICZα-A vector and recombinantly produced in the P.pastoris X-33 strain for the first time.

Polyhydroxyalkanoates have attracted great interest as a suitable alternative to petrochemical based plastics due to their outstanding properties such as biodegradability and biocompatibility. However, the biggest problem in the production of microbial polyhydroxyalkanoates is low cost-effectiveness. In this study, polyhydroxyalkanoate production was carried out using waste substrates with local isolates. Culture conditions were optimized to increase the polyhydroxyalkanoate production potential. The produced polyhydroxyalkanoate was characterized by FTIR analyses, and its metabolic pathway was determined by real-time PCR. According to the results, the best polyhydroxyalkanoate producer bacteria was characterized as Pseudomonas neustonica NGB15. The optimal culture conditions were detected as 30 g/L banana peel powder, 25 °C temperature, pH 8, and 4-day incubation time. Under the optimized conditions, 3.34 g/L PHA production was achieved. As a result of FTIR analyses, major peaks were obtained at 1723, 1277, 1261, 1097, 1054, and 993 cm−1. These peaks represent that the type of produced polyhydroxyalkanoate was poly-β-hydroxybutyrate. According to gene expression profile of NGB15, it was determined that Pseudomonas neustonica NGB15 produces PHA using the de novo fatty acid synthesis metabolic pathway. In conclusion, poly-β-hydroxybutyrate production by Pseudomonas neustonica NGB15 using a low-cost fermentation medium has been shown to be biotechnologically promising.

In humans, excess accumulation of reactive oxygen species (ROS) produces oxidative stress, resulting in cell and tissue damage, and eventually, leading to variety of diseases. Excess ROS can be eliminated, and its detrimental repercussions avoided by combining endogenous and exogenous antioxidants. A plant-based diet and dietary supplements are a major source of exogenous antioxidants; however, fungi, bacteria, lichens, insects, and algae (macroalgae and microalgae) are also deemed as potential sources for exogenous antioxidants. For example, algal biomass and extracts can be directly consumed or their purified metabolites can be used as antioxidants. Furthermore, some exogenous antioxidant molecules can be synthesized only by algae but not by other organisms. Antioxidant molecules derived from algae, include a variety of polysaccharides, pigments (carotenoids, phycobiliproteins etc), mycosporins-like amino acids, phytosterols, phenolic compounds (phenolic acids, bromophenols, phlorotannins, flavonoids etc), fatty acids, and alkaloids. They exhibit potent antioxidant activities confirmed by in vitro scavenging assays (DPPH, ABTS, hydroxyl, superoxide, hydrogen peroxide and nitric oxide radicals) and/or by reducing or chelating metal ions. In addition, algal-derived antioxidants have also been tested in in vivo models and have demonstrated high antioxidant activities achieved by upregulation of antioxidant enzymes (catalase, superoxide dismutase and glutathione peroxidase) and inhibition of lipid peroxidation. This review study focuses on the antioxidant potential of different natural compounds obtained from different algal groups (macroalgae, eukaryotic microalgae and prokaryotic microalgae). This review is based primarily on research and review articles published in the last five years (2019-2023) and written in English.

ABSTRACTThis study aimed to isolate, purify, and characterize a lipase from the gut symbiont Bacillus megaterium F25 (GenBank accession: MF597792) of the aquatic insect Rhantus suturalis, with a focus on its potential applications in biodiesel and food industries. Under optimized culture conditions, B. megaterium F25 could produce 583 U/L of lipase in shaking flask culture. The purified lipase (PL) exhibited a specific activity with 113.89 U/mg, and its molecular weight was determined as 34 kDa. The activity of PL was enhanced by methanol, ethanol, Tween‐80, Triton X‐100, Ca2+, and Mg2+, while β‐mercaptoethanol, EDTA, SDS, Fe2+, Mn2+, and Cu2+ were inhibitory. PL showed optimal activity and stability at neutral and slightly acidic pHs, as well as in a temperature range of 20°C–30°C. PL displayed strong hydrolytic activity toward plant oils and animal fats, indicating its potency for both the food industry and the remediation of oil‐contaminated environments. When tested as a catalyst, PL provided biodiesel production with a transesterification yield of 86.8% under optimized conditions (36 h reaction time, 4 mL enzyme solution, 30°C, pH 7.0, and waste cooking oil:methanol ratio of 10 mL/40 mL). This is the first report on the lipase‐producing potential of gut microbial symbionts of aquatic insects. Furthermore, B. megaterium lipase was tested for the first time as a biocatalyst for biodiesel production.

In this study the extracellular proteins from the isolate LC3 belonging to Aspergillus were purified for new antimicrobial polypeptide (AMP) discovery and then tested for antimicrobial activity against Staphylococcus aureus (ATCC 25923) and Methicillin-resistant S. aureus (MRSA). Antimicrobial activity was determined by the trypsin/proteinase K assay, which was polypeptide-based, and it was observed that this protein was a protein of about 11 kDa by gel overlay assay. The minimum inhibitory concentration of purified AMP molecule against S. aureus ATCC 25923 and MRSA was 8 µg/ml and 32 µg/ml, respectively and the AMP molecule was confirmed. ITS sequence analysis showed that isolate LC3 was identified as Aspergillus niger, using the Bioedit sequence assembly program. The sequence was deposited with the GenBank database with accession number MK332597. The results indicate that the purified AMP molecule has the potential to be used in infections caused by S. aureus.

COVID-19 is a disease that have affected the entire world, and it continues to spread with new variants. A patient's innate immune system plays a critical role in the mild and severe transition of COVID-19. Antimicrobial peptides (AMPs), which are important components of the innate immune system, are potential molecules to fight pathogenic bacteria, fungi, and viruses. Human β-defensin 2 (hBD-2), a 41-amino-acid antimicrobial peptide, is one of the defensins inducibly expressed in the skin, lungs, and trachea in humans. In this study, it was aimed to investigate the interaction of hBD-2 produced recombinantly in Pichia pastoris with the human angiotensin-converting enzyme 2 (ACE-2) under in vitro conditions. First, hBD-2 was cloned in P. pastoris X-33 via the pPICZαA vector, a yeast expression platform, and its expression was confirmed by SDS-PAGE, western blotting, and qRT-PCR. Then, the interaction between recombinant hBD-2 and ACE-2 proteins was revealed by a pull-down assay. In light of these preliminary experiments, we suggest that the recombinantly produced hBD-2 may be protective against SARS-CoV-2 and be used as a supplement in treatment. However, current findings need to be supported by cell culture studies, toxicity analyses, and in vivo experiments.

Hydrophobins are amphipathic proteins with small molecular weights produced in filamentous fungi. These proteins are highly stable due to the disulfide bonds formed between the protected cysteine residues. They have great potential for usage in many different fields such as surface modifications, tissue engineering, and drug transport systems because hydrophobins are surfactants and soluble in harsh mediums. In this study, it was aimed to determine the hydrophobin proteins responsible for the hydrophobicity of the super-hydrophobic fungi isolates in the culture medium and to carry out the molecular characterization of the hydrophobin producer species. As a result of measuring surface hydrophobicity by determining the water contact angle, five different fungi with the highest hydrophobicity were classified as Cladosporium by classical and molecular (ITS and D1-D2 regions) methods. Also, protein extraction according to the recommended method for obtaining hydrophobins from spores of these Cladosporium species indicated that the isolates have similar protein profiles. Ultimately, the isolate named A5 with the highest water contact angle was identified as Cladosporium macrocarpum, and the 7 kDa band was appointed as a hydrophobin since it was the most abundant protein in protein extraction for this species.

In this article, nisin(N)-loaded poly lactic-co-glycolic acid (PLGA) nanoparticles (NPs) were prepared using the single-solvent evaporation method with a rhamnolipid(R) cosurfactant. The antibacterial–antibiofilm effects of the prepared formulation and free nisin were evaluated against S. aureus (ATCC 25923). The characterization of NPs was analyzed using scanning electron microscopy (SEM), Zetasizer and Fourier-transform infrared spectroscopy (FTIR). The drug encapsulation efficiency and loading capacity percentages of NPs were calculated by the spectrophotometric method. The drug release of N-loaded PVA-R-PLGA NPs was determined by the dialysis bag method. The antibacterial and antibiofilm activity of N-PVA-R-PLGA NPs was determined. PVA-R-PLGA-NPs were found to be spherical with sizes of ~140 nm, according to the SEM analysis and surface charge of N-PVA-R-PLGA NPs −53.23 ± 0.42 mV. The sustained release of N (≥72% after 6 h) was measured in PVA-R-PLGA-NPs. The encapsulation efficiency percentage of N-PVA-R-PLGA NP was 78%. The MIC values of free nisin and N-PVA-R-PLGA NPs were 256 μg/mL and 64 μg/mL, respectively. The antibiofilm inhibition percentages of free nisin and N-PVA-R-PLGA NPs were 28% and 72%, respectively. These results reveal that N-PVA-R-PLGA NPs are a promising formulation for use in infections caused by S. aureus compared to free nisin.

In this study, fluconazole (FLZ) loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) were prepared with two different formulations consisting of polyvinyl alcohol (PVA) and PVA-rhamnolipid (R) in order to improve antibiofilm activity against Candida albicans ATCC 90028. The encapsulation efficiency, drug loading capacity, in-vitro release, characterization and antibiofilm activity of these formulations were compared. Characterization of NPs were analyzed by scanning electron microscopy (SEM) and Zetasizer. Drug loading capacity and encapsulation efficiency percentages were measured by spectrophotometric method. PLGA-NPs were spherical in shape with mean sizes of ~300 nm and surface charge of FLZ loaded PVA and PVA-R-PLGA NPs -25,9±1.99, -48,1±2.46, respectively. Sustained release of FLZ (≥60% after 6 h) were obtained in PVA-R PLGA-NPs. The encapsulation efficiency percentages of PVA-FLZ-PLGA and PVA-R-FLZ-PLGA were 50% and 85%, respectively. Antibiofilm inhibition percentages are 55% and 63%, respectively. These results show that the PVA-R-FLZ-PLGA drug delivery system is a new therapeutic approach that can be used in infections caused by C. albicans.

Nowadays, due to the rapid spread of antibiotic resistance and the difficulty of discovering new antimicrobial agents, the reuse and combinational strategies of old antibiotics have come to the fore. In this study, we investigated the combinational efficacy of nisin and chloramphenicol against the ATCC 6538 strain of Staphylococcus aureus. The MIC values of nisin and chloramphenicol were >64 and 32 µg/mL, respectively. The checkerboard assay was carried out for the inspection of synergism between nisin and chloramphenicol. Furthermore, the crystal violet assay was employed to assess antibiofilm effects. Additionally, the expressions of various virulence genes (agrA, spa, icaA and saeR) were investigated using the colony biofilm assay and qRT-PCR methods. In combination application, MIC values of nisin and chloramphenicol was decreased. In addition, biofilm formation was decreased.It was shown that the expression level of the agrA gene decreased compared to the control in the nisin, chloramphenicol and combinational applications. The expression levels of other genes were increased compared to the control. The results showed that the activities of nisin and chloramphenicol combinations had synergistic and antibiofilm activity. This study sheds light on the combinatorial use of older antibiotics.

Prostate cancer (PCa) is one of the most prevalent cancer types among males. Differential expression of microRNAs is associated with various cancers including PCa. Although mature microRNAs are preferentially located in the cytoplasm, several studies identified mature human microRNAs in purified nuclei and miR-145 has been found to be predominantly expressed in the nuclei of benign tissues compared to tumor lesions. However, the nuclear functions of miR-145 are yet limited. Here, we aimed at investigating the inductive role of miR-145 on the expression of Semaphorin 3A (SEMA3A) in PCa cell lines. To study the regulatory potential of miR-145 in the transcriptional level in PCa, we overexpressed miR-145 in PC3 and DU145 cells, and confirmed its upregulation by quantitative-real-time-PCR. Then we investigated the tumor suppressor potential of miR-145 upon inducing SEMA3A expression using cell viability assay, western blot analysis, Chromatin Immunoprecipitation assay and luciferase reporter assay. Our results revealed that p53, miR-145, and SEMA3A expressions are significantly downregulated in PC3 and DU145 cells compared to nontumorigenic prostate epithelial PNT1a cells. miR-145 overexpression in PCa cells induced the expression of SEMA3A at both messenger RNA and protein levels. Furthermore, increased miR-145 expression enriched RNA Pol-II antibody on the promoter of SEMA3A and induced luciferase activity controlled by SEMA3A promoter. In this study, we showed that the functions of miR-145 are not limited to gene silencing, and found that it may lead to changes in gene expression in the transcriptional level.

Kernels of loquat (Eriobotrya japonica L.) fruits are rich in protein and starch contents; however, they have no significant application in world. This study was performed to produce pigments from Monascus purpureus ATCC16365 using loquat kernel powder (LKP) as a fermentation substrate and investigate the effect of four mineral salts (CaCl2, KH2PO4, MgSO4, and FeSO4) on pigment production in LKP-based medium. During the experiments, LKP was not subjected to any chemical or enzymatic hydrolysis, and it was tested directly as a substrate in shaking flask and fermenter cultures. It was found that addition of CaCl2 alone decreased red pigment production but did not cause an important change in synthesis of yellow and orange pigments. Supplementation of KH2PO4, MgSO4, or FeSO4 alone decreased the production of yellow pigment but increased the production of red pigments. When three salts (1.0 g/L KH2PO4, 0.3 g/L MgSO4, and 0.03 g/L FeSO4) were added together to the LKP-based medium, more productions of enzymes (protease and amylase) and red pigments were achieved. When experiments were performed in optimized medium (LKP and three mineral salts), maximum concentrations of red, orange, and yellow pigments were determined as 292, 193, and 171 AU/L in flask culture but 327, 241, and 204 AU/L in fermenter culture, respectively. Amylase and protease activities were 93.4 and 52.3 U/L in flask culture but 93.8 and 52.8 U/L in fermenter culture, respectively. This is the first report on the use of LKP as a substrate in production of enzymes and pigments from M. purpureus.

In the present study, 120 fungal isolates were locally isolated from soil and selected according to their ability to antimicrobial activity. Then, selected isolates were tested for their ability to prevent biofilm formation and only one isolate (A01) showed an antibiofilm effect. The isolate A01 identified as Aspergillus tubingensis by sequencing of the 18S ITS region and a segment of beta-tubulin gene. Then, 5 fractions were prepared from the culture filtrate of A. tubingensis A01 using the ultrafiltration technique to find active polypeptide fraction. The experiments revealed that one of them had an antibiofilm activity. The MALDI-TOF/MS analyses demonstrated that this polypeptide composed of 92 amino acids and had a molecular mass of 10,087 Da. The sequence alignment showed homology with hypothetical protein (OJI81679.1). The gene coding for this polypeptide consisting of 279 nucleotides, herein we called astucin, was cloned and sequenced from A. tubingensis A01 to confirm results. The MIC of the purified polypeptide was 32 m/L and 128 mu g/mL and the MBIC was 2 and 8 mu g/mL against Staphylococcus aureus and MRSA, respectively. The results demonstrated that the antimicrobial and antibiofilm activity of astucin, together with its lack of cytotoxicity, makes it an alternative for application in medicine. Significance: Antibiotic resistance is a global problem and the emergence of antibiotic resistant bacteria reduce the effect the current treatment approaches. In this context, antimicrobial peptides stand out as potentional agents to combat bacterial infection especially, biofilm related infections. Importantly, this study have greatly considered our understanding for fungal derived antibiofilm polypeptides. In this study, traditional selection method combined with crystal violet assay is used to investigate antibiofilm polypeptides. We identified antibiofilm polypeptides purified from A. tubingensis A01. This protein shows antimicrobial and antibiofilm activity against S. aureus.