Genomic insights into Penicillium chrysogenum adaptation to subseafloor sedimentary environments.

BACKGROUND: Penicillium chrysogenum is a filamentous fungal species with diverse habitats, yet little is known about its genetics in adapting to extreme subseafloor sedimental environments. RESULTS: Here, we report the discovery of P. chrysogenum strain 28R-6-F01, isolated from deep coal-bearing sediments 2306 m beneath the seafloor. This strain possesses exceptional characteristics, including the ability to thrive in extreme conditions such as high temperature (45 °C), high pressure (35 Mpa), and anaerobic environments, and exhibits broad-spectrum antimicrobial activity, producing the antibiotic penicillin at a concentration of 358 µg/mL. Genome sequencing and assembly revealed a genome size of 33.19 Mb with a GC content of 48.84%, containing 6959 coding genes. Comparative analysis with eight terrestrial strains identified 88 unique genes primarily associated with penicillin and aflatoxins biosynthesis, carbohydrate degradation, viral resistance, and three secondary metabolism gene clusters. Furthermore, significant expansions in gene families related to DNA repair were observed, likely linked to the strain's adaptation to its environmental niche. CONCLUSIONS: Our findings provide insights into the genomic and biological characteristics of P. chrysogenum adaptation to extreme anaerobic subseafloor sedimentary environments, such as high temperature and pressure.

Screening of pathogenicity-deficient Penicillium italicum mutants established by Agrobacterium tumefaciens-mediated transformation.

Blue mold, caused by Penicillium italicum, is one of the main postharvest diseases of citrus fruits during storage and marketing. The pathogenic mechanism remains largely unclear. To explore the potential pathogenesis-related genes of this pathogen, a T-DNA insertion library of P. italicum PI5 was established via Agrobacterium tumefaciens-mediated transformation (ATMT). The system yielded 200-250 transformants per million conidia, and the transformants were genetically stable after five generations of successive subcultures on hygromycin-free media. 2700 transformants were obtained to generate a T-DNA insertion library of P. italicum. Only a few of the 200 randomly selected mutants exhibited significantly weakened virulence on citrus fruits, with two mutants displaying attenuated sporulation. The T-DNA in the two mutants existed as a single copy. Moreover, the mutant genes PiBla (PITC_048370) and PiFTF1 (PITC_077280) identified may be involved in conidia production by regulating expressions of the key regulatory components for conidiogenesis. These results demonstrated that the ATMT system is useful to obtain mutants of P. italicum for further investigation of the molecular mechanisms of pathogenicity and the obtained two pathogenesis-related genes might be novel loci associated with pathogenesis and conidia production.

Genomic, transcriptomic, and ecological diversity of Penicillium species in cheese rind microbiomes.

Although Penicillium molds can have significant impacts on agricultural, industrial, and biomedical systems, the ecological roles of Penicillium species in many microbiomes are not well characterized. Here we utilized a collection of 35 Penicillium strains isolated from cheese rinds to broadly investigate the genomic potential for secondary metabolism in cheese-associated Penicillium species, the impact of Penicillium on bacterial community assembly, and mechanisms of Penicillium-bacteria interactions. Using antiSMASH, we identified 1558 biosynthetic gene clusters, 406 of which were mapped to known pathways, including several mycotoxins and antimicrobial compounds. By measuring bacterial abundance and fungal mRNA expression when culturing representative Penicillium strains with a cheese rind bacterial community, we observed divergent impacts of different Penicillium strains, from strong inhibitors of bacterial growth to those with no impact on bacterial growth or community composition. Through differential mRNA expression analyses, Penicillium strains demonstrated limited differential gene expression in response to the bacterial community. We identified a few shared responses between the eight tested Penicillium strains, primarily upregulation of nutrient metabolic pathways, but we did not identify a conserved fungal response to growth in a multispecies community. These results in tandem suggest high variation among cheese-associated Penicillium species in their ability to shape bacterial community development and highlight important ecological diversity within this iconic genus.

Microbial associates of the elm leaf beetle: uncovering the absence of resident bacteria and the influence of fungi on insect performance.

Microbial symbionts play crucial roles in the biology of many insects. While bacteria have been the primary focus of research on insect-microbe symbiosis, recent studies suggest that fungal symbionts may be just as important. The elm leaf beetle (ELB, Xanthogaleruca luteola) is a serious pest species of field elm (Ulmus minor). Using culture-dependent and independent methods, we investigated the abundance and species richness of bacteria and fungi throughout various ELB life stages and generations, while concurrently analyzing microbial communities on elm leaves. No persistent bacterial community was found to be associated with the ELB or elm leaves. By contrast, fungi were persistently present in the beetle's feeding life stages and on elm leaves. Fungal community sequencing revealed a predominance of the genera Penicillium and Aspergillus in insects and on leaves. Culture-dependent surveys showed a high prevalence of two fungal colony morphotypes closely related to Penicillium lanosocoeruleum and Aspergillus flavus. Among these, the Penicillium morphotype was significantly more abundant on feeding-damaged compared with intact leaves, suggesting that the fungus thrives in the presence of the ELB. We assessed whether the detected prevalent fungal morphotypes influenced ELB's performance by rearing insects on (i) surface-sterilized leaves, (ii) leaves inoculated with Penicillium spores, and (iii) leaves inoculated with Aspergillus spores. Insects feeding on Penicillium-inoculated leaves gained more biomass and tended to lay larger egg clutches than those consuming surface-sterilized leaves or Aspergillus-inoculated leaves. Our results demonstrate that the ELB does not harbor resident bacteria and that it might benefit from associating with Penicillium fungi.IMPORTANCEOur study provides insights into the still understudied role of microbial symbionts in the biology of the elm leaf beetle (ELB), a major pest of elms. Contrary to expectations, we found no persistent bacterial symbionts associated with the ELB or elm leaves. Our research thus contributes to the growing body of knowledge that not all insects rely on bacterial symbionts. While no persistent bacterial symbionts were detectable in the ELB and elm leaf samples, our analyses revealed the persistent presence of fungi, particularly Penicillium and Aspergillus on both elm leaves and in the feeding ELB stages. Moreover, when ELB were fed with fungus-treated elm leaves, we detected a potentially beneficial effect of Penicillium on the ELB's development and fecundity. Our results highlight the significance of fungal symbionts in the biology of this insect.

Mutual regulation of novel transcription factors RsrD and RsrE positively modulates the production of raw-starch-degrading enzyme in Penicillium oxalicum.

Filamentous fungi can produce raw-starch-degrading enzyme, however, regulation of production of raw-starch-degrading enzyme remains poorly understood thus far. Here, two novel transcription factors raw-starch-degrading enzyme regulator D (RsrD) and raw-starch-degrading enzyme regulator E (RsrE) were identified to participate in the production of raw-starch-degrading enzyme in Penicillium oxalicum. Individual knockout of rsrD and rsrE in the parental strain Δku70 resulted in 31.1%-92.9% reduced activity of raw-starch-degrading enzyme when cultivated in the presence of commercial starch from corn. RsrD and RsrE contained a basic leucine zipper and a Zn2Cys6-type DNA-binding domain, respectively, but with unknown functions. RsrD and RsrE dynamically regulated the expression of genes encoding major amylases over time, including raw-starch-degrading glucoamylase gene PoxGA15A and α-amylase gene amy13A. Interestingly, RsrD and RsrE regulated each other at transcriptional level, through binding to their own promoter regions; nevertheless, both failed to bind to the promoter regions of PoxGA15A and amy13A, as well as the known regulatory genes for regulation of amylase gene expression. RsrD appears to play an epistatic role in the module RsrD-RsrE on regulation of amylase gene expression. This study reveals a novel regulatory pathway of fungal production of raw-starch-degrading enzyme.IMPORTANCETo survive via combating with complex extracellular environment, filamentous fungi can secrete plant polysaccharide-degrading enzymes that can efficiently hydrolyze plant polysaccharide into glucose or other mono- and disaccharides, for their nutrients. Among the plant polysaccharide-degrading enzymes, raw-starch-degrading enzymes directly degrade and convert hetero-polymeric starch into glucose and oligosaccharides below starch gelatinization temperature, which can be applied in industrial biorefinery to save cost. However, the regulatory mechanism of production of raw-starch-degrading enzyme in fungi remains unknown thus far. Here, we showed that two novel transcription factors raw-starch-degrading enzyme regulator D (RsrD) and raw-starch-degrading enzyme regulator E (RsrE) positively regulate the production of raw-starch-degrading enzyme by Penicillium oxalicum. RsrD and RsrE indirectly control the expression of genes encoding enzymes with amylase activity but directly regulate each other at transcriptional level. These findings expand diversity of gene expression regulation in fungi.

Dynamic changes in and correlations between microbial communities and physicochemical properties during the composting of cattle manure with Penicillium oxalicum.

BACKGROUND: Penicillium oxalicum is an important fungal agent in the composting of cattle manure, but the changes that occur in the microbial community, physicochemical factors, and potential functions of microorganisms at different time points are still unclear. To this end, the dynamic changes occurring in the microbial community and physicochemical factors and their correlations during the composting of cattle manure with Penicillium oxalicum were analysed. RESULTS: The results showed that the main phyla observed throughout the study period were Firmicutes, Actinobacteria, Proteobacteria, Bacteroidetes, Halanaerobiaeota, Apicomplexa and Ascomycota. Linear discriminant analysis effect size (LEfSe) illustrated that Chitinophagales and Eurotiomycetes were biomarker species of bacteria and eukaryote in samples from Days 40 and 35, respectively. Bacterial community composition was significantly correlated with temperature and pH, and eukaryotic microorganism community composition was significantly correlated with moisture content and NH4+-N according to redundancy analysis (RDA). The diversity of the microbial communities changed significantly, especially that of the main pathogenic microorganisms, which showed a decreasing trend or even disappeared after composting. CONCLUSIONS: In conclusion, a combination of high-throughput sequencing and physicochemical analysis was used to identify the drivers of microbial community succession and the composition of functional microbiota during cattle manure composting with Penicillium oxalicum. The results offer a theoretical framework for explaining microecological assembly during cattle manure composting with Penicillium oxalicum.

An industrial perspective on metabolic responses of Penicillium chrysogenum to periodic dissolved oxygen feast-famine cycles in a scale-down system.

While traveling through different zones in large-scale bioreactors, microbes are most likely subjected to fluctuating dissolved oxygen (DO) conditions at the timescales of global circulation time. In this study, to mimic industrial-scale spatial DO gradients, we present a scale-down setup based on dynamic feast/famine regime (150 s) that leads to repetitive cycles with rapid changes in DO availability in glucose-limited chemostat cultures of Penicillium chrysogenum. Such DO feast/famine regime induced a stable and repetitive pattern with a reproducible metabolic response in time, and the dynamic response of intracellular metabolites featured specific differences in terms of both coverage and magnitude in comparison to other dynamic conditions, for example, substrate feast/famine cycles. Remarkably, intracellular sugar polyols were considerably increased as the hallmark metabolites along with a dynamic and higher redox state (NADH/NAD+) of the cytosol. Despite the increased availability of NADPH for penicillin production under the oscillatory DO conditions, this positive effect may be counteracted by the decreased ATP supply. Moreover, it is interesting to note that not only the penicillin productivity was reduced under such oscillating DO conditions, but also that of the unrecyclable byproduct ortho-hydroxyphenyl acetic acid and degeneration of penicillin productivity. Furthermore, dynamic flux profiles showed the most pronounced variations in central carbon metabolism, amino acid (AA) metabolism, energy metabolism and fatty acid metabolism upon the DO oscillation. Taken together, the metabolic responses of P. chrysogenum to DO gradients reported here are important for elucidating metabolic regulation mechanisms, improving bioreactor design and scale-up procedures as well as for constructing robust cell strains to cope with heterogenous industrial culture conditions.

Biotransformation approach to produce rare ginsenosides F1, compound Mc1, and Rd2 from major ginsenosides.

The stems and leaves of Panax notoginseng contain high saponins, but they are often discarded as agricultural waste. In this study, the predominant ginsenosides Rg1, Rc, and Rb2, presented in the stems and leaves of ginseng plants, were biotransformed into value-added rare ginsenosides F1, compound Mc1 (C-Mc1), and Rd2, respectively. A fungal strain YMS6 (Penicillium sp.) was screened from the soil as a biocatalyst with high selectivity for the deglycosylation of major ginsenosides. Under the optimal fermentation conditions, the yields of F1, C-Mc1, and Rd2 were 97.95, 68.64, and 79.58%, respectively. This study provides a new microbial resource for the selective conversion of protopanaxadiol-type and protopanaxatriol-type major saponins into rare ginsenosides via the whole-cell biotransformation and offers a solution for the better utilization of P. notoginseng waste.

Transcriptome-wide analysis of a superior xylan degrading isolate Penicillium oxalicum 5-18 revealed active lignocellulosic degrading genes.

Lignocellulose biomass raw materials have a high value in energy conversion. Recently, there has been growing interest in using microorganisms to secret a series of enzymes for converting low-cost biomass into high-value products such as biofuels. We previously isolated a strain of Penicillium oxalicun 5-18 with promising lignocellulose-degrading capability. However, the mechanisms of lignocellulosic degradation of this fungus on various substrates are still unclear. In this study, we performed transcriptome-wide profiling and comparative analysis of strain 5-18 cultivated in liquid media with glucose (Glu), xylan (Xyl) or wheat bran (WB) as sole carbon source. In comparison to Glu culture, the number of differentially expressed genes (DEGs) induced by WB and Xyl was 4134 and 1484, respectively, with 1176 and 868 genes upregulated. Identified DEGs were enriched in many of the same pathways in both comparison groups (WB vs. Glu and Xly vs. Glu). Specially, 118 and 82 CAZyme coding genes were highly upregulated in WB and Xyl cultures, respectively. Some specific pathways including (Hemi)cellulose metabolic processes were enriched in both comparison groups. The high upregulation of these genes also confirmed the ability of strain 5-18 to degrade lignocellulose. Co-expression and co-upregulated of genes encoding CE and AA CAZy families, as well as other (hemi)cellulase revealed a complex degradation strategy in this strain. Our findings provide new insights into critical genes, key pathways and enzyme arsenal involved in the biomass degradation of P. oxalicum 5-18.

N-linked glycosylation affects catalytic parameters and fluctuation of the active center of Aspergillus awamori exo-inulinase.

Heterogeneous expression of enzymes allows large-scale production with reduced costs. Changes in glycosylation often occur due to changes in the expression host. In the study, the catalytic and biochemical properties of Aspergillus awamori exo-inulinase 1 are compared for A. awamori and Penicillium verruculosum expression hosts. The tertiary structure contains seven sites of N-glycosylation, with two of them located near the active center. If expressed in P. verruculosum, the enzyme was four times less glycosylated and two times more active toward sucrose, raffinose, and stachyose due to an increase in kcat. These substrates with a short chain of 2-4 monosaccharide units were used to characterize the interaction of the substrate with the amino acid residues in the active center while preventing the interaction of the substrate with N-linked glycans. Molecular dynamics simulations showed an increase in the fluctuation of the active center with an increase in the length of N-linked glycans. The fluctuation of the residues N40 and Q57, which interact with the hydroxyl group O5 of the fructose unit in the -1 subsite of the active center, was increased by 1.6 times. The fluctuation of the residue W335, which interacts with the hydroxyl group O1 of the fructose unit together with the catalytic residue D41 and affects the torsion angle geometry of the substrate molecules, was increased by 1.5 times. The residue R188, which analogously to W335 affects the torsion angle geometry of the substrate molecules, was also among the affected residues with a 1.2-fold increase in the fluctuation.

The colorful fungi of the Chilean forests: Production, chemical characterization and possible applications of their pigments.

In Chile, as in the rest of the world, only a small fraction of the fungal diversity inhabiting the wide variety of its ecosystems is known. This diversity must hide an inestimable richness of species with interesting biotechnological potential, including fungal pigment producers. Recently, interest in filamentous fungi has increased significantly due to their importance as alternative sources of pigments and colorants that are environmentally and human health friendly. As a result, fungal pigments are gaining importance in various industrial applications, such as food, textiles, pharmaceuticals, cosmetics, etc. The increasing consumer demand for "green label" natural colorants requires the exploration of different ecosystems in search of new fungal species that are efficient producers of different pigment with a wide range of colors and ideally without the co-production of mycotoxins. However, advances are also needed in pigment production processes through fermentation, scale-up from laboratory to industrial scale, and final product formulation and marketing. In this respect, the journey is still full of challenges for scientists and entrepreneurs. This chapter describes studies on pigment-producing fungi collected in the forests of central-southern Chile. Aspects such as the exploration of potential candidates as sources of extracellular pigments, the optimization of pigment production by submerged fermentation, methods of pigment extraction and purification for subsequent chemical characterization, and formulation (by microencapsulation) for potential cosmetic applications are highlighted. This potential use is due to the outstanding bioactivity of most fungal pigments, making them interesting functional ingredients for many applications. Finally, the use of fungal pigments for textile and spalting applications is discussed.

Penicillium chrysogenum: Beyond the penicillin.

Almost one century after the Sir Alexander Fleming's fortuitous discovery of penicillin and the identification of the fungal producer as Penicillium notatum, later Penicillium chrysogenum (currently reidentified as Penicillium rubens), the molecular mechanisms behind the massive production of penicillin titers by industrial strains could be considered almost fully characterized. However, this filamentous fungus is not only circumscribed to penicillin, and instead, it seems to be full of surprises, thereby producing important metabolites and providing expanded biotechnological applications. This review, in addition to summarizing the classical role of P. chrysogenum as penicillin producer, highlights its ability to generate an array of additional bioactive secondary metabolites and enzymes, together with the use of this microorganism in relevant biotechnological processes, such as bioremediation, biocontrol, production of bioactive nanoparticles and compounds with pharmaceutical interest, revalorization of agricultural and food-derived wastes or the enhancement of food industrial processes and the agricultural production.

Genome sequencing and analysis of penicillin V producing Penicillium rubens strain BIONCL P45 isolated from India.

BACKGROUND: A filamentous fungus Penicillium rubens is widely recognized for producing industrially important antibiotic, penicillin at industrial scale. OBJECTIVE: To better comprehend, the genetic blueprint of the wild-type P. rubens was isolated from India to identify the genetic/biosynthetic pathways for phenoxymethylpenicillin (penicillin V, PenV) and other secondary metabolites. METHOD: Genomic DNA (gDNA) was isolated, and library was prepared as per Illumina platform. Whole genome sequencing (WGS) was performed according to Illumina NovoSeq platform. Further, SOAPdenovo was used to assemble the short reads validated by Bowtie-2 and SAMtools packages. Glimmer and GeneMark were used to dig out total genes in genome. Functional annotation of predicted proteins was performed by NCBI non-redundant (NR), UniProt, Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Ontology (GO) databases. Moreover, secretome analysis was performed by SignalP 4.1 and TargetP v1.1 and carbohydrate-active enzymes (CAZymes) and protease families by CAZy database. Comparative genome analysis was performed by Mauve 2.4.0. software to find genomic correlation between P. rubens BIONCL P45 and Penicillium chrysogenum Wisconsin 54-1255; also phylogeny was prepared with known penicillin producing strains by ParSNP tool. RESULTS: Penicillium rubens BIONCL P45 strain was isolated from India and is producing excess PenV. The 31.09 Mb genome was assembled with 95.6% coverage of the reference genome P. chrysogenum Wis 54-1255 with 10687 protein coding genes, 3502 genes had homologs in NR, UniProt, KEGG, and GO databases. Additionally, 358 CAZymes and 911 transporter coding genes were found in genome. Genome contains complete pathways for penicillin, homogentisate pathway of phenyl acetic acid (PAA) catabolism, Andrastin A, Sorbicillin, Roquefortine C, and Meleagrin. Comparative genome analysis of BIONCL P45 and Wis 54-1255 revealed 99.89% coverage with 2952 common KEGG orthologous protein-coding genes. Phylogenetic analysis revealed that BIONCL P45 was clustered with Fleming's original isolate P. rubens IMI 15378. CONCLUSION: This genome can be a helpful resource for further research in developing fermentation processes and strain engineering approaches for high titer penicillin production.

Lead remediation by geological fluorapatite combined with Penicillium Oxalicum and Red yeast.

Phosphate solubilizing fungi Penicillium oxalicum (POX) and Red yeast Rhodotorula mucilaginosa (Rho) have been applied in Pb remediation with the combination of fluorapatite (FAp), respectively. The secretion of oxalic acid by POX and the production of extracellular polymers (EPS) by Rho dominate the Pb remediation. In this study, the potential of Pb remediation by the fungal combined system (POX and Rho) with FAp was investigated. After six days of incubation, the combination of POX and Rho showed the highest Pb remove ratio (99.7%) and the lowest TCLP-Pb concentration (2.9 mg/L). The EPS combined with POX also enhanced Pb remediation, which has a 99.3% Pb removal ratio and 5.5 mg/L TCLP-Pb concentration. Meanwhile, Rho and EPS can also stimulate POX to secrete more oxalic acid, which reached 1510.1 and 1450.6 mg/L in six days, respectively. The secreted oxalic acid can promote FAp dissolution and the formation of lead oxalate and pyromorphite. Meanwhile, the EPS produced by Rho can combine with Pb to form EPS-Pb. In the combined system of POX + Rho and POX + EPS, all of the lead oxalate, pyromorphite, and EPS-Pb were observed. Our findings suggest that the combined application of POX and Rho with FAp is an effective approach for enhancing Pb remediation.

Talaromyces marneffei, Coccidioides species, and Paracoccidioides species-a systematic review to inform the World Health Organization priority list of fungal pathogens.

The World Health Organization, in response to the growing burden of fungal disease, established a process to develop a fungal pathogen priority list. This systematic review aimed to evaluate the epidemiology and impact of infections caused by Talaromyces marneffei, Coccidioides species, and Paracoccidioides species. PubMed and Web of Sciences databases were searched to identify studies published between 1 January 2011 and 23 February 2021 reporting on mortality, complications and sequelae, antifungal susceptibility, preventability, annual incidence, and trends. Overall, 25, 17, and 6 articles were included for T. marneffei, Coccidioides spp. and Paracoccidioides spp., respectively. Mortality rates were high in those with invasive talaromycosis and paracoccidioidomycosis (up to 21% and 22.7%, respectively). Hospitalization was frequent in those with coccidioidomycosis (up to 84%), and while the duration was short (mean/median 3-7 days), readmission was common (38%). Reduced susceptibility to fluconazole and echinocandins was observed for T. marneffei and Coccidioides spp., whereas >88% of T. marneffei isolates had minimum inhibitory concentration values ≤0.015 µg/ml for itraconazole, posaconazole, and voriconazole. Risk factors for mortality in those with talaromycosis included low CD4 counts (odds ratio 2.90 when CD4 count <200 cells/µl compared with 24.26 when CD4 count <50 cells/µl). Outbreaks of coccidioidomycosis and paracoccidioidomycosis were associated with construction work (relative risk 4.4-210.6 and 5.7-times increase, respectively). In the United States of America, cases of coccidioidomycosis increased between 2014 and 2017 (from 8232 to 14 364/year). National and global surveillance as well as more detailed studies to better define sequelae, risk factors, outcomes, global distribution, and trends are required.

Severe pneumonia with pleural effusion caused by co-infection of Paecilomyces variotii and Penicillium oxalicum in a diabetic patient.

BACKGROUND PAECILOMYCES: and Penicillium are considered as rare opportunistic pathogens in immunocompromised hosts, and pneumonia caused by Paecilomyces and Penicillium is rare. In this study, we present first case of severe pneumonia with pleural effusion caused by co-infection of Paecilomyces variotii (P. variotii) and Penicillium oxalicum (P. oxalicum) in a 66-year-old female with poorly controlled type 2 diabetes. CASE PRESENTATION: A 56-year-old woman patient presented to hospital for nausea, poor appetite, and vomiting for one day. On the second day of admission, blood culture and renal puncture fluid culture grew multidrug-resistant Escherichia coli (imipenem/cilastatin sensitive), and she received combination therapy with imipenem/cilastatin (1 g, every 8 h) and vancomycin (0.5 g, every 12 h). On the fourth day, she developed symptoms of respiratory failure. Pulmonary computed tomography (CT) showed an increase in pneumonia compared to before, with minor pleural effusion on both sides. Two fungi were isolated repeatedly from BALF culture, which were confirmed as P. variotii and P. oxalicum by Internal transcribed spacer (ITS) sequencing. Her pleural effusion was completely absorbed, pneumonia symptoms have significantly improved and discharged with receiving liposomal amphotericin B treatment for four weeks. CONCLUSIONS: It is worth noting that clinicians and laboratory personnel should not simply consider Paecilomyces and Penicillium species as contaminants, especially in immunocompromised patients. Early fungal identification and antifungal drug sensitivity are crucial for clinical drug selection and patient prognosis.

Dual Regulatory Role of Penicillium oxalicum SL2 in Soil: Phosphorus Solubilization and Pb Stabilization.

The mechanisms of the P. oxalicum SL2-mediated microbial community on phosphorus solubilization and Pb stabilization were investigated through a 90-day soil experiment. In the treatments inoculated with P. oxalicum SL2, the amount of P. oxalicum SL2-GFP remained at 77.8%-138.6% of the initial inoculation amount after 90 days, and the available phosphorus (AP) content increased 21.7%-40.8% while EDTA-Pb decreased 29.9%-43.2% compared with CK treatment. SEM-EDS results showed that P. oxalicum SL2 changed the agglomeration degree of microaggregates and promoted the combination of Pb with C and O elements. These phenomena were enhanced when applied with Ca3(PO4)2. Microbial community analysis showed that P. oxalicum SL2 improved soil microbial activity, in which the fungi absolute abundance increased about 15 times within 90 days. Correlation analyses and a partial least-squares path model showed that the activation of Penicillium, Ascobolus, Humicola, and Spizellomyces in a fungal community increased the content of oxalate and AP, which directly decreased EDTA-Pb content, while the change of Bacillus, Ramlibacter, Gemmatimonas, and Candidatus Solibacter in the bacterial community regulated Fe/Mn/S/N cycle-related functions, thus promoting the conversion of Pb to oxidizable state. Our findings highlight that P. oxalicum SL2 enhanced the microbial-induced phosphate precipitation process by activating soil microbial communities and regulating their ecological functions.

Discovery of 23,24-diols containing ergosterols with anti-neuroinflammatory activity from Penicillium citrinum TJ507.

Citristerones A-E (1-5), five new 23,24-diols containing ergosterols, along with three known analogues, were isolated from the endophytic fungus Penicillium citrinum TJ507 obtained from Hypericum wilsonii N. Robson. Their structures and absolute configurations were determined by NMR, HRESIMS, Snatzke's method, X-ray diffraction analyses and ECD calculation. Subsequently, the anti-neuroinflammatory effects of these isolates were screened using lipopolysaccharide (LPS)-induced BV-2 microglial cells, and citristerone B (2) showed outstanding anti-neuroinflammatory activity, with IC50 value of 0.60 ± 0.04 µM. Moreover, immunofluorescence and western blot analysis suggested that citristerone B not only reduced the release of nitric oxide (NO) and proinflammatory cytokines in LPS-induced BV-2 microglial cells, but also significantly inhibited the expression of TNF-α, iNOS and NF-κB, along with the production of cellular ROS.

Bialorastins A-F, highly oxygenated and polycyclic andrastin-type meroterpenoids with proangiogenic activity from the deep-sea cold-seep-derived fungus Penicillium bialowiezense CS-283.

Six new highly oxygenated and polycyclic andrastin-type meroterpenoids, namely, bialorastins A-F (1-6), were discovered from the culture of Penicillium bialowiezense CS-283, a fungus isolated from the deep-sea cold seep squat lobster Shinkaia crosnieri. The planar structures and absolute configurations of these compounds were determined by detailed analysis of spectroscopic data, single crystal X-ray diffraction, and TDDFT-ECD calculations. Structurally, bialorastin A (1) represents a rare 17-nor-andrastin that possesses an unusual 2-oxaspiro[4.5]decane-1,4-dione moiety with a unique 6/6/6/6/5 polycyclic system, while bialorastin B (2) is also a 17-nor-andrastin featuring a gem-propane-1,2-dione moiety. Additionally, bialorastins C-E (3-5) possess a 6/6/6/6/5/5 fused hexacyclic skeleton, characterized by distinctive 3,23-acetal/lactone-bridged functionalities. All isolated compounds were evaluated for their proangiogenic activities in transgenic zebrafish. Compound 3 exhibited significant proangiogenic activity, which notably increased the number and length of intersegmental blood vessels in model zebrafish in a dose-dependent manner at concentrations of 20 and 40 µM. On a molecular scale, the tested compounds were modeled through molecular docking to have insight into the interactions with the possible target VEGFR2. Mechanistically, RT-qPCR results revealed that compound 3 could promote angiogenesis via activating VEGFR2 and subsequently activating the downstream PI3K/AKT and MAPK signaling pathways. These findings indicate that 3 could be a potential lead compound for developing angiogenesis agents.

Anti-diabetic and anti-inflammatory indole diterpenes from the marine-derived fungus Penicillium sp. ZYX-Z-143.

Seven new indole-diterpenoids, penpaxilloids A-E (1-5), 7-methoxypaxilline-13-ene (6), and 10-hydroxy-paspaline (7), along with 20 known ones (8-27), were isolated from the marine-derived fungus Penicillium sp. ZYX-Z-143. Among them, compound 1 was a spiro indole-diterpenoid bearing a 2,3,3a,5-tetrahydro-1H-benzo[d]pyrrolo[2,1-b][1,3]oxazin-1-one motif. Compound 2 was characterized by a unique heptacyclic system featuring a rare 3,6,8-trioxabicyclo[3.2.1]octane unit. The structures of the new compounds were established by extensive spectroscopic analyses, NMR calculations coupled with the DP4 + analysis, and ECD calculations. The plausible biogenetic pathway of two unprecedented indole diterpenoids, penpaxilloids A and B (1 and 2), was postulated. Compound 1 acted as a noncompetitive inhibitor against protein tyrosine phosphatase 1B (PTP1B) with IC50 value of 8.60 ± 0.53 µM. Compound 17 showed significant α-glucosidase inhibitory activity with IC50 value of 19.96 ± 0.32 µM. Moreover, compounds 4, 8, and 22 potently suppressed nitric oxide production on lipopolysaccharide-stimulated RAW264.7 macrophages.