Aspergillus Niger Research Articles

Synthesis, Characterization and Antimicrobial Activity of Mixed Antibiotic-Vitamin Metal Complexes Involving Metronidazole and Vitamin B1 (Thiamine)

Antimicrobial resistance (AMR) poses a critical threat to global health, making it imperative to develop novel therapeutic strategies. This study focuses on the synthesis and characterization of mixed antibiotic-vitamin metal complexes involving metronidazole and vitamin B1. Metal complexes, known for their unique structural properties, were synthesized with Nickel, Zinc, and Iron salts to enhance the biological efficacy of the parent antibiotics. These complexes were analyzed using various physicochemical methods, including ultraviolet-visible and infrared spectroscopy, and were evaluated for their solubility, elemental composition, and melting points. The antimicrobial activity of the synthesized complexes was tested against bacterial strains such as Streptococcus feacalis, Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus, as well as fungal strains like Aspergillus niger and Candida albicans. The results demonstrated that the metal complexes exhibited enhanced antibacterial and antifungal properties compared to the free ligands. Specifically, the zinc and nickel complexes showed significant inhibition against Klebsiella pneumoniae and Aspergillus niger, respectively. This study highlights the potential of metal complexes as promising agents to combat AMR, providing a foundation for future research into drug development and clinical applications.

Effect of Microgravity on Rare Earth Elements Recovery by Burkholderia cepacia and Aspergillus niger

Rare earth elements (REEs) are indispensable in modern industry and technology, driving an urgent demand for innovative, eco-friendly recovery technologies. As space exploration advances, the impact of microgravity on microorganisms has become a focal point, yet the effects on microbial growth and REEss recovery remain uncharted. This study investigates the biosorption of REEs by Burkholderia cepacia (B. cepacia) and Aspergillus niger (A. niger) from a mixed solution containing La, Ce, Pr, Nd, Sm, Er, and Y under varying initial concentrations, pH levels, and microgravity conditions. We observed that the medium’s pH rose with B. cepacia and fell with A. niger when cultured in normal gravity conditions, suggesting distinct metabolic responses. Notably, microgravity significantly altered microbial morphology and metabolite profiles, significantly enhancing REEs recovery efficiency. Specifically, the recovery of B. cepacia of Ce and Pr peaked at 100%, and A. niger achieved full recovery of all tested REEs at pH 1.5 (suboptimal growth conditions). This study pioneers the application of biosorption for the recovery of REEs in microgravity conditions, presenting a promising strategy for future resource exploitation by space biomining.

Synthesis, characterization, DFT computational studies and biological activity of transition metal complexes derived from 4-(((6-nitrobenzo[d]thiazol-2-yl)imino)methyl)benzene-1,3-diol

A series of Co(II), Ni(II), Cu(II), Zn(II) complexes have been synthesized with a benzothiazole azo dye containing tridentate (NNO) donor ligand 4-(((6-nitrobenzo[d]thiazol-2-yl)imino)methyl)benzene-1,3-diol derived from 2-amino-6-nitrobenzothiazole and 2,4-dihydroxybenzaldehyde. The structures of the novel ligand and metal complexes were identified and confirmed via various spectroscopic techniques (FT-IR,1H NMR,13C NMR, UV-Vis, mass spectrometry), TGA-DTA, powder X-ray diffraction, and DFT calculations. The optimal structural parameters and chemical reactivity of the ligand and metal complexes have been investigated using Density Functional Theory calculations (DFT/B3LYP,6-31G** and LanL2DZ basis sets) to provide insight about their frontier molecular orbitals (FMO) and molecular electrostatic potential (MESP). In vitro DPPH radical scavenging techniques have been used to assess the antioxidant activity of the ligand and complexes, indicating good antioxidant activity. The Ni(II) complex was the most potent with the lowest IC50 values. The in vitro antibacterial activities have been explored by screening against bacteria (Bacillus subtilis) and bacteria (E. coli) exhibiting significant activity against the tested strains of bacteria with Zn(II) complex as most potent with the lowest MIC value against E. coli and B. subtilis) and highest zone of inhibition against E. coli and B. subtilis at 1000 μg/mL concentration). The antifungal activity of complexes against Aspergillus niger and Candida albicans indicate that the Co(II) complex is most active for C. albicans and Zn(II) complex for A. niger .

Expediting the bioactivity of zinc sulfide nanoparticles with copper oxide as a nanocomposite

The regulatory role of zinc in bone formation extends to the activation of proteins associated with bone homeostasis. Furthermore, copper is well known for its antibacterial properties. This dual function underscores the significance of zinc and copper in maintaining a balance of bone structure and function. In light of the aforementioned, zinc sulphide/copper oxide nanocomposites were created in this instance using a straightforward coprecipitation technique. Copper oxide was used as a nanocomposite to improve the structural, morphological, and biological performance of zinc sulphide nanoparticles. The X-ray diffraction pattern confirmed a transformation in the crystal structure from cubic to rhombohedral, along with increase in intensity. Fourier transforms infrared analysis indicated the presence of functional groups. Scanning electron microscopy images demonstrated a morphological shift from non-uniform to distinct spherical nanoparticles, impacting the enhancement of material properties. The pathogenic activity of the zinc sulphide/copper oxide nanocomposites was tested against nine bacterial strains. In antimicrobial testing, zinc sulphide/copper oxide nanocomposites showed promising results, particularly against Klebsiella pneumoniae (zone of inhibition: 14 mm at 100 µg/mL compared to 7 mm by standard) and Escherichia coli (zone of inhibition: 11 mm at 100 µg/mL compared to 10 mm by standard) after 24 h with zone of inhibition matching or exceeding that of the standard (chloramphenicol). Zinc sulphide nanoparticles and zinc sulphide/copper oxide nanocomposites were evaluated for their antifungal activity against fungal stains from Trichophyton rubrum, Aspergillus niger, and Aspergillus flavus. After a 24-h period, it was discovered that zinc sulphide/copper oxide nanocomposites were effective against Aspergillus flavus (zone of inhibition: 19.4 mm at 100 µg/mL compared to 6.3 mm by standard) at all concentrations (25–100 mg/mL), with zones of inhibition identical to or greater than those of the standard (fluconazole). Certainly, based on these results, zinc sulphide/copper oxide nanocomposites could be promising materials for drug delivery.Clinical trial registration: Not applicable.

Bioconversion of mango peels into itaconic acid through submerged fermentation and statistical optimization of parameters through response surface methodology.

Itaconic acid is an industrially crucial organic acid due to its broad range of applications. The main hurdle in itaconic acid production is the high cost of the substrate, i.e., pure glucose, required for the fermentation process. Pakistan annually produces about 1.7 to 1.8 million metric tonnes of mango fruit. Keeping this in view, the potential of a sugar-rich fruit by-product, i.e., mango peels, was analyzed to be used as a substrate for the biosynthesis of itaconic acid using Aspergillus niger by submerged fermentation. Different physicochemical parameters (incubation period, temperature, agitation rate, inoculum size, and pH) were optimized using the central composite design (CCD) design of response surface methodology (RSM). The maximum production of itaconic acid, i.e., 4.6 g/L, was analyzed using 10% mango peels w/v (water hydrolysate), 3 mL inoculum volume after 5 days of fermentation period at pH 3, and a temperature of 32 °C when the media was kept at a 200-rpm agitation speed. The itaconic acid extraction from mango peels was done using the solvent extraction method using n-butanol. The identification and quantification of itaconic acid produced in the study were done using the Fourier Transform Infrared Spectroscopy (FTIR) spectrum and the High-Performance Liquid Chromatography (HPLC) method. According to HPLC analysis, 98.74% purity of itaconic acid was obtained in the research. Hence, it is concluded from the results that sugar-rich mango peels can act as a promising substrate for the biosynthesis of itaconic acid. Further conditions can be optimized at the bioreactor level to meet industrial requirements.

Pathological and Fungal Isolation study of dog skin disease in Iraq Governorates

Dogs are susceptible to several types of infectious diseases can be worrisome for their owner because some of them are fatal if not treated soon enough. Fungal infection can be contracted through different parts of body furthermore many of them are zoonotic infection among human and dogs the signs of any disease typical depend on location of infection either local or system infection. Local infection usually involves skin surface that look like wound the objective of this study was to briefly about the most common pathogenic fungal infection in dogs by describing information about the causative agent, clinical signs and grossly appearance with histopathological change skin examination current study were done on 200 dogs collected in Iraq governorates (Baghdad, Erbil, Anbar, Sulaymaniyah) during a period 6 months (January – June) 2023. 200 examined dogs with different age, breed and sex ( k9, ornamental and stray dogs ) were observed fungal isolation and pathological examination with clinical signs by using diagnostic tools for skin biopsies (biopsy punch) from suspected infected skin dogs. Results showed pathogenic fungi after collected on fungal culture for detection pathogenic fungal (Dermatophyte Test Agar) D.T.M Agar Base. Fungal isolation constitutes the following pathogenic fungi (100 infected samples from 200 suspected samples). 60% Aspergillus niger, 30% Trichophyton Verrucosum, 10% Alternaria spp. Clinical signs and grossly lesion showed complete skin ulcer, allopecia, odema, abscessation while microscopic appearance revealed skin ulcer, hyperkeratosis, folliculitis, necrosis, apoptosis, pyogranuloma and granulation tissue with septate hyphae in skin dermis and epidermis which infected with Aspergillus niger.

Competition between homologous chromosomal DNA and exogenous donor DNA to repair CRISPR/Cas9-induced double-strand breaks in Aspergillus niger

BackgroundAspergillus niger is well-known for its high protein secretion capacity and therefore an important cell factory for homologous and heterologous protein production. The use of a strong promoter and multiple gene copies are commonly used strategies to increase the gene expression and protein production of the gene of interest (GOI). We recently presented a two-step CRISPR/Cas9-mediated approach in which glucoamylase (glaA) landing sites (GLSs) are introduced at predetermined sites in the genome (step 1), which are subsequently filled with copies of the GOI (step 2) to achieve high expression of the GOI.ResultsHere we show that in a ku70 defective A. niger strain (Δku70), thereby excluding non-homologous end joining (NHEJ) as a mechanism to repair double-stranded DNA breaks (DSBs), the chromosomal glaA locus or homologous GLSs can be used to repair Cas9-induced DSBs, thereby competing with the integration of the donor DNA containing the GOI. In the absence of exogenously added donor DNA, the DSBs are repaired with homologous chromosomal DNA located on other chromosomes (inter-chromosomal repair) or, with higher efficiency, by a homologous DNA fragment located on the same chromosome (intra-chromosomal repair). Single copy inter-chromosomal homology-based DNA repair was found to occur in 13–20% of the transformants while 80–87% of the transformants were repaired by exogenously added donor DNA. The efficiency of chromosomal repair was dependent on the copy number of the potential donor DNA sequences in the genome. The presence of five homologous DNA sequences, resulted in an increased number (35–61%) of the transformants repaired by chromosomal DNA. The efficiency of intra-chromosomal homology based DSB repair in the absence of donor DNA was found to be highly preferred (85–90%) over inter-chromosomal repair. Intra-chromosomal repair was also found to be the preferred way of DNA repair in the presence of donor DNA and was found to be locus-dependent.ConclusionThe awareness that homologous chromosomal DNA repair can compete with donor DNA to repair DSB and thereby affecting the efficiency of multicopy strain construction using CRISPR/Cas9-mediated genome editing is an important consideration to take into account in industrial strain design.

Identification of cotton non-pathogenic fungal agent isolates based on morphological and MALDI-TOF mass spectrometry method

In this study, morphological and MALDI-TOF MS identification and comparison of non-pathogenic fungal species isolated from diseased root, leaf and boll tissues of cotton plants were carried out. For this purpose, surveys were conducted in Bağlar, Sur, Çınar, Bismil, Yenişehir, Ergani, Eğil, Kayapınar and Silvan districts of Diyarbakır province where cotton production is intensive between June and September 2020 and 2021. 209 samples of plants showing typical fungal disease symptoms were collected from 75 different cotton production areas. A total of 171 fungal isolates were obtained by isolation, culture and purification procedures from diseased plant tissues in the samples. The 20 isolates that were negative in the pathogenicity test in the main host were identified and compared by morphological (traditional) and MALDI-TOF MS methods. According to the results, Aspergillus niger, Aspergillus flavus, Aspergillus terreus, Aspergillus fumigatus, Aspergillus minisclerotigenes, Penicillium nalgıovense, Chaetomium globosum, Dichotomopilus funicola, Arthroderma gloria, Pseudogmnoacus pannorum, Tichophyton interdigitale, and Penicillium sp. Penicillium sp. were found to be intensively colonized in different parts of cotton such as leaves, bolls and roots. Again, it was determined that the most common species among the total saprophyte isolates was Aspergillus niger with a high similarity rate.

Antibacterial and antifungal activities of Platycladus orientalis leaf extract-mediated Fe2O3 and Ce-doped Fe2O3 nanoparticles

Green synthesis of nanomaterials harnesses naturally occurring materials, including plant extracts, to offer environmentally friendly alternatives to conventional biomedicine, agriculture, and other field applications. This study explores the green route to Fe2O3 and cerium-doped Fe2O3 (Ce-doped Fe2O3) nanoparticles synthesized for the first time using the leaf extract of Platycladus orientalis. The synthesized nanoparticles were characterized for their structural, morphological, chemical, and optical properties. The hematite phase of Fe2O3 nanoparticles with spherical morphology was obtained. The introduction of Ce as a dopant into Fe2O3 increased the lattice strain of Ce-doped Fe2O3 nanoparticles (0.51%) compared to pristine Fe2O3 (0.46%) even though the size of both nanomaterials was similar. Compared to pristine Fe2O3 nanoparticles, Ce-doped Fe2O3 nanoparticles also demonstrated enhanced antimicrobial and antifungal activities against Escherichia coli, Enterococcus faecalis, Listeria monocytogenes, Penicillium chrysogenum, Aspergillus niger, and Mucor mucedo. The green-synthesized Ce-doped Fe2O3 nanoparticles possess potential for application in biomedical and environmental fields based on their relevance to human health and food safety, diversity in microbial characteristics, and potential for resistance to conventional treatments.

Identification of resistant sources against collar rot disease in groundnut (Arachis hypogaea) incited by Aspergillus niger

Collar rot disease incited by Aspergillus niger van Tiegham is one of the major constraint to groundnut (Arachis hypogaea L.) production in India. This fungus is ubiquitous, soil inhabitant causing severe reduction in seed germination. Infected seeds appear surrounded by black conidia and post-emergence infection occurs on collar region of plants leading to mortality of emerged seedlings at the seedling stage. Therefore, present study was carried out during rainy (kharif) seasons of 2022 and 2023 at Regional Research Station (CCS Haryana Agricultural University, Hisar, Haryana), Bawal, Haryana to identify the strategy of disease management by identification of new resistant lines which will be useful to develop introgression lines using marker-assisted backcrossing approach to improve disease resistance against soil-borne pathogens in popular groundnut varieties. A total of 245 groundnut genotypes were screened under natural epiphytotic field conditions in randomized block design (RBD) with three replications for their resistance against collar rot disease The results of the investigation indicated that 65 genotypes displayed resistant reactions among which ICGV-6285, GC-131-1, ICGV-06319, ICGV-02038, GC-100, GC-98, ICGV-02038, ICGV-7403, ICGV-7214, TG-37A and GC-133 exhibited the lowest collar rot incidence while, rest of the genotypes displayed moderately resistant, susceptible and highly susceptible reaction. Thus, these resistant genotypes could be utilized in the hybridization programme to develop high yielding groundnut variety with inbuilt resistance against collar rot of groundnut.

The Mycobiota of Library Books in Russia.

Abstract-Numerous studies of microorganisms isolated from the surface of cultural heritage objects, including library documents, are regularly carried out in different countries. Although the micromycete composition in each case varies, some species are constantly isolated. The structure of micromycete communities that inhabit library documents was studied in 57 cities of Russia located in seven federal districts (Northwestern, Central, Southern, Volga, Ural, Siberian, and Far Eastern). Micromycetes of 95 species from 32 genera were isolated and identified. The mycobiota of the library documents represented by Ascomycota has more than 90% of the species richness; Mucoromycota make up 3-9% and Basidiomycota, 3-4%. The Aspergillaceae family was the leading family: it accounted for 48.5-67.3% of the total species richness. In all regions, species diversity is moderate: the Shannon index ranged from 2.7 to 3.3. The Mcintosh species richness index is high everywhere (48-126), except in the Ural district (15.3). The McIntosh (0.76-0.84) and Pielow (0.80-0.91) dominance indices indicate a high level of species evenness in the mycobiota. The obtained values demonstrate the stability the document mycobiota in libraries from different regions. Significant species similarity between the districts was revealed by calculation of binary coefficients: the Jaccard coefficient was from 0.44 to 0.60; the Sørensen's qualitative measure of similarity was from 0.63 to 0.75; the quantitative similarity measure of Sørensen was from 0.44 to 0.71, and Morisita-Horn was from 0.66 to 1.0. The groups of dominant species in different regions are quite similar. The study of the ecological diversity of mycobiota on library books demonstrated the moderate diversity and the stability of the community. A high degree of similarity of taxonomic structures was established regardless of the climate conditions of the regions. Cosmopolitans characterized by high frequency of occurrence formed the major core of the library book mycobiota: Alternaria alternata, Aspergillus niger, Cladosporium cladosporioides, Mucor plumbeus, and Penicillium aurantiogriseum.

Antifungal activities of Pediococcus pentosaceus LWQ1 and Lactiplantibacillus plantarum LWQ17 isolated from sourdough and their efficacies on preventing spoilage of Chinese steamed bread

The short shelf life of Chinese steamed bread (CSB) at room temperature due to moldy contamination restricts its popularity. This study aimed to evaluate two selected lactic acid bacteria strains, namely Lactiplantibacillus plantarum LWQ17 (LWQ17) and Pediococcus pentosaceus LWQ1 (LWQ1), on their antifungal activities and potential applications in CSB making. The results showed that both strains, especially LWQ17, displayed remarkable inhibition against Aspergillus niger and Penicillium polonicum, the representative species found in CSB spoilage. LWQ17 and LWQ1 destroyed the cell membranes of the fungi and caused a loss of intracellular substances. When applied in CSB making, both strains could delay the germination of mold on the surface of CSB in a season-dependent way. LWQ17 delayed the germination of mold by 4 d in Spring and Winter, while 1 d in Summer and Autumn. Further study revealed that their antifungal activities were greatly influenced by temperatures and humidity. Both strains could completely inhibit the germination of mold during two weeks of storage under 37 °C but with different humidity levels. Moreover, our results demonstrated that acidic substances were crucial in inhibiting the fungi, while proteinic substances and hydrogen peroxide played an auxiliary role. Analysis of their acids by targeted metabolomics showed that LWQ17 produced more kinds of acids, and the amount of phenyllactic acid produced by LWQ17 was 60 times higher than that produced by LWQ1, which may explain its better antifungal efficacy. This study provides a reference for employing lactic acid bacteria in CSB preservation under different conditions.

Infectious Complications in Pediatric Hematopoietic Stem Cell Transplantation Recipients in Northeast Mexico

Abstract Background Hematopoietic stem cell transplantation (HSCT) is a potentially curative therapy for an increasing number of neoplastic and hematological diseases. However, these patients are at high risk of acquiring infections due to a complex interaction involving organ dysfunction, tissue damage, pathogen exposure, pathogen virulence, and the overall state of dynamic immunosuppression varying according to different phases of immunologic reconstitution after HSCT, and the need for immunosuppressants to prevent and treat non-infectious complications such as graft-versus-host disease (GVHD). Methods All patients under 16 years old who underwent HSCT at the “Dr. José Eleuterio González” University Hospital, a referral center in Northeast Mexico, from March 2019 to October 2023, were included. Clinical, epidemiological, and analytical characteristics of the patients and infectious episodes during pre-engraftment, early engraftment, and late engraftment periods were analyzed. Results In the studied period, a total of 75 patients underwent HSCT, of whom 52 (69%) experienced infectious events (IEs). A total of 136 IEs were documented, averaging 2.5 IEs per patient. Among these, 40% were viral infections, 33% bacterial, 6.6% fungal, 0.7% parasitic, and 19.3% were indeterminate. The most prevalent baseline diagnoses were acute lymphoblastic leukemia (52%), acute myeloid leukemia (19%), and aplastic anemia (12%). Seventy-two percent of the patients underwent a haploidentical stem cell transplantation, and the graft was sourced from peripheral blood stem cells in 75% of the population. Bacterial infections were predominant in the pre-engraftment period, whereas viral infections were more frequent in early and late engraftment. The distribution of these IEs by period is shown in Figure 1. Among bacterial infections, bloodstream infections (BSIs) accounted for 56%, followed by skin and soft tissue infections (14%) and gastroenteritis (13%). Of the 26 BSI events, 73% were caused by Gram-negative bacilli, including 8 cases of Escherichia coli (42%), 6 cases of Pseudomonas aeruginosa (32%), 2 cases of Klebsiella pneumoniae (11%), and 1 case each of Acinetobacter calcoaceticus, Salmonella enterica and Stenotrophomonas maltophilia (5%). 44% of these exhibited extended-spectrum beta-lactamase (ESBL), and 19% were carbapenem-resistant. The remaining 27% of BSI were caused by Gram-positive cocci: Staphylococcus epidermidis (43%), Streptococcus viridans group (29%), Staphylococcus aureus, and Rothia mulcilaginosa (14% each). 17% of all BSI were central line associated bloodstream infection (CLABSI). Among viral infections, cytomegalovirus (CMV) was the most frequent agent at 46%, followed by SARS-CoV-2 and BK virus at 14% and 11%, respectively. Among the fungal infections, we identified 9 cases of invasive fungal disease (IFD), four cases of possible IFD, two of probable IFD and three cases of proven IFD were identified, including one case each of mucormycosis (zygomycetes), Candida tropicalis fungemia, and Aspergillus niger pneumonia. Additionally, one case of intestinal giardiasis, was identified, accounting for 0.7% of the total. Conclusion Infections represent one of the major adverse events in patients undergoing HSCT. It is essential to understand the local epidemiology in each hospital center to tailor international guidelines to the available resources in each institution, which is crucial in improving strategies for preventing, detecting, and providing timely treatment for these infectious complications and their clinical outcomes. Figure 1. Distribution of infectious events among the post-HSTC periods.

Antimicrobial Activity of Honey and Propolis from Alba County, Romania.

Investigating the quality of bee products obtained across different geographical regions and analyzing their antimicrobial activity is of significant interest to various scientific disciplines. This study focuses on comparing the antimicrobial activity of honey and propolis samples from different areas of Alba County, Romania. The quality parameters of five samples of two types of bee products (honey and propolis) were assessed. Then, the samples were tested to comparatively determine their antimicrobial properties against 12 species of bacteria (Escherichia coli, Salmonella typhimurium, Salmonella enteritidis, Salmonella anatum, Salmonella choleraesuis, Pseudomonas aeruginosa, Pseudomonas fluorescens, Staphylococcus aureus, Staphylococcus epidermidis, Bacillus cereus, Bacillus subtilis, and Listeria monocytogenes) and 7 fungal strains (Candida albicans, Aspergillus niger, Aspergillus flavus, Penicillium chrysogenum, Rhizopus stolonifer, Fusarium oxysporum, and Alternaria alternata). Of the bacterial strains, the most sensitive to the action of honey samples were the two strains of Staphylococcus followed by P. fluorescens. The two strains of Pseudomonas and L. monocytogenes were the most sensitive to the activity of propolis. Of the fungal strains, F. oxysporum was the most sensitive to the actions of both honey and propolis, followed by P. chrysogenum in the case of honey samples and the two Aspergillus strains in the case of propolis. These findings indicate that bee products are rich sources of bioactive compounds exhibiting strong antimicrobial properties and significant potential for the development of new phytopharmaceutical products.

Biodiversity of Aspergillus Species and Their Mycotoxin Production Potential in Dry Meat.

This study aimed to examine fungi diversity in dried beef meat sold in Ekiti State, characterize the isolated fungi, and determine the aflatoxin-producing ability of the Aspergillus fungi in the samples. Dried beef meat was collected from different markets in Ekiti State and screened for the presence of filamentous fungi using molecular methods. Samples were cultured aseptically on potato dextrose agar (PDA) for fungi isolation, and molecular identification was performed using DNA extraction, Polymerase chain Reaction (PCR), ITS-1/ITS-4 primer pair, and nucleotide sequencing. The results obtained indicated a range of filamentous fungi genera including Aspergillus, Rhizopus, Penicillium, Fusarium, Cladosporium, Alternaria, and other fungi species contaminating the dried meat at (43%), (42%), (3%), (2%), (2%), (1%), and (7%), respectively. High incidences were recorded for Aspergillus flavus, Aspergillus niger, and Aspergillus fumigatus in most of the screened samples. Aspergillus flavus accounted for (24.7%) of all the Aspergillus species isolated with the presence of the gene needed for aflatoxin production. The occurrences of these filamentous fungal species pose a cause for concern, as most of these fungal species are known producers of certain toxic substances. Maximum likelihood phylogenetic analysis showed a high similarity index score, which indicated a good relationship between isolated Aspergillus Species and the closely related strains from GenBank, isolated from different sources and countries. The implication of this study is that consumer health may be at risk through exposure to contaminated dried meat.

Biosynthesis of Iron Oxide Nanoparticles by Marine Streptomyces sp. SMGL39 with Antibiofilm Activity: In Vitro and In Silico Study

One of the major global health threats in the present era is antibiotic resistance. Biosynthesized iron oxide nanoparticles (FeNPs) can combat microbial infections and can be synthesized without harmful chemicals. In the present investigation, 16S rRNA gene sequencing was used to discover Streptomyces sp. SMGL39, an actinomycete isolate utilized to reduce ferrous sulfate heptahydrate (FeSO4.7H2O) to biosynthesize FeNPs, which were then characterized using UV–Vis, XRD, FTIR, and TEM analyses. Furthermore, in our current study, the biosynthesized FeNPs were tested for antimicrobial and antibiofilm characteristics against different Gram-negative, Gram-positive, and fungal strains. Additionally, our work examines the biosynthesized FeNPs’ molecular docking and binding affinity to key enzymes, which contributed to bacterial infection cooperation via quorum sensing (QS) processes. A bright yellow to dark brown color shift indicated the production of FeNPs, which have polydispersed forms with particle sizes ranging from 80 to 180 nm and UV absorbance ranging from 220 to 280 nm. Biosynthesized FeNPs from actinobacteria significantly reduced the microbial growth of Fusarium oxysporum and L. monocytogenes, while they showed weak antimicrobial activity against P. aeruginosa and no activity against E. coli, MRSA, or Aspergillus niger. On the other hand, biosynthesized FeNPs showed strong antibiofilm activity against P. aeruginosa while showing mild and weak activity against B. subtilis and E. coli, respectively. The collaboration of biosynthesized FeNPs and key enzymes for bacterial infection exhibits hydrophobic and/or hydrogen bonding, according to this research. These results show that actinobacteria-biosynthesized FeNPs prevent biofilm development in bacteria.

Green-synthesized carbon dots from ginger: Multifunctional agents against oral pathogens with biocompatibility in human gingival fibroblast cells

Persistent antibiotic use in treating oral infections often leads to drug resistance in pathogenic bacteria, notably impacting conditions like periodontitis. Addressing this challenge, the study pioneers the use of carbon dots (CDs) synthesized from ginger rhizomes (Zingiber officinale) as a novel biocompatible material. CDs were synthesized via the hydrothermal method, emphasizing a green approach, and comprehensively characterized for their optical properties and structural uniformity. The synthesized CDs showed a zeta potential of −24.9 mV, confirming the formation of stable and well-dispersed particles. Dynamic Light Scattering (DLS) confirmed an average particle size of 2.9 nm, thus validating the formation of CDs. Biomedical assessments demonstrated that the synthesized CDs were non-cytotoxic to human gingival fibroblast cell lines, with effective free radical scavenging activity and high total antioxidant capacity, as indicated by their IC50 values. CDs also exhibited moderate inhibition of protein denaturation compared to the standard. Moreover, they showed significant inhibitory effects against bacterial strains (Pseudomonas aeruginosa, Lactobacillus acidophilus, Escherichia coli, Staphylococcus aureus) and fungal strains (Aspergillus niger, Candida albicans) at minimal concentrations. Notably, CDs inhibited the growth of periodontal pathogens including Aggregatibacter actinomycetemcomitans, Tannerella forsythia, Porphyromonas gingivalis, and Prevotella intermedia. These findings underscore the potential of CDs as multifunctional agents possessing anti-inflammatory, antifungal, antioxidant, and antibacterial properties. Remarkably, they offer a promising alternative to conventional antibiotics, potentially revolutionizing oral healthcare. Their proven biocompatibility and potent bioactivity underscore their innovative potential in biomedical research. Future studies should further assess their efficacy in vivo to fully harness their clinical potential.

Investigation on the influence of GPI-AP for the production of malic acid in Aspergillus niger

Based on the potential of microbial fermentation in the sustainable and environmentally friendly production of L-malic acid (L-MA), this study aims to investigate the effect of glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) on enhancing the stability of Aspergillus niger (A. niger) cell wall to increase L-MA production. Through experiments, we discovered and screened GPI2, a GPI-anchored cell surface glycoprotein, and confirmed for the first time that it has a promoting effect on L-MA, a metabolite of A. niger. This recombinant strain RG0098 that overexpressed gpi2 showed an increase in cell wall thickness and robustness, a decrease in intracellular reactive oxygen species (ROS) levels, which improved the antioxidant capacity. After 108 h of fermentation, the production of L-MA reached 114.7 ± 2.12 g/L, and the productivity was 1.06 ± 0.025 g/L/h. The strain RG0098 has enhanced the productivity of L-MA by a notable margin of 49.7 %. This study provides a sustainable and environmentally friendly pathway for the production of L-MA through microbial fermentation.

Transcriptomics identify the triggering of citrate export as the key event caused by manganese deficiency in Aspergillus niger.

Citric acid is produced on industrial scale by batch fermentation of the filamentous fungus Aspergillus niger. High-yield citric acid production requires a low (<5 ppb) manganese(II) ion concentration in the culture broth. However, the requirement for this deficiency has not been investigated on a functional genomics level. Here, we compared the transcriptome of a citric acid hyper-producer A. niger strain grown under citric acid-producing conditions in 6-L scale bioreactors at Mn2+ ion-deficient (5 ppb) and Mn2+ ion-sufficient (100 ppb) conditions at three early time points of cultivation. We observed that Mn2+ deficiency triggers an upregulation of the citrate exporter gene cexA and provides functional evidence that this event is responsible for citrate overflow. In addition to the industrial relevance, this is the first study that examined the role of Mn2+ ion deficiency in a heterotrophic eukaryotic cell on a genome-wide scale.

Therapeutic Importance of Extracts from Leaf and Bark of &lt;i&gt;Gymnacranthera farquhariana&lt;/i&gt;

Background: Gymnacranthera farquhariana (Hook. f. and Thomson) Warb. is one of the endangered tree taxon of the Western Ghats, a biodiversity hot-spot in peninsular India. Very few reports are available on biological applications of the bark, leaf and seed of this plant. Aim: The present work deals with the screening of methanol and aqueous extracts of G. farquhariana from leaf and bark for therapeutic importance. Methods: Anti-bacterial activities of extracts were carried out using two bacterial strains viz., Pseudomonas aeruginosa and Staphylococcus aureus through the agar well diffusion method. The antifungal activities by poison bait method using Aspergillus niger, Colletotrichum gloeosporioides and Fusarium solani. Each experimental parameter was conducted in triplicate. Results: The results showed that G. farquhariana bark and leaf extracts exhibited promising activities against bacteria. Antifungal activity also showed good inhibition activity. The extracts showed a good anti-diabetic potential in α-amylase inhibitory assay. Bark aqueous extract showed 54.79% inhibition for α- amylase inhibition assay at 250μL. The extract also showed good anti-inflammatory potential in the Bovine Serum Albumin (BSA) denaturation assay. Bark aqueous extract showed 83.9% inhibition for BSA denaturation assay at 100 μL. Conclusion: Both leaf and bark extracts of the plant showed good antioxidant, anti-diabetic and antimicrobial activity. This is the first such in vitro report concerning G. farquhariana plant parts.