Possible role of fungal hemolysins in sick building syndrome

Polyenic Antibiotics and Other Antifungal Compounds Produced by Hemolytic Streptomyces Species

Streptomyces are of great interest in the pharmaceutical industry as they produce a plethora of secondary metabolites that act as antibacterial and antifungal agents. They may thrive on their own in the soil, or associate with other organisms, such as plants or invertebrates. Some soil-derived strains exhibit hemolytic properties when cultivated on blood agar, raising the question of whether hemolysis could be a virulence factor of the bacteria. In this work we examined hemolytic compound production in 23 β-hemolytic Streptomyces isolates; of these 12 were soil-derived, 10 were arthropod-associated, and 1 was plant-associated. An additional human-associated S. sp. TR1341 served as a control. Mass spectrometry analysis suggested synthesis of polyene molecules responsible for the hemolysis: candicidins, filipins, strevertene A, tetrafungin, and tetrin A, as well as four novel polyene compounds (denoted here as polyene A, B, C, and D) in individual liquid cultures or paired co-cultures. The non-polyene antifungal compounds actiphenol and surugamide A were also identified. The findings indicate that the ability of Streptomyces to produce cytolytic compounds (here manifested by hemolysis on blood agar) is an intrinsic feature of the bacteria in the soil environment and could even serve as a virulence factor when colonizing available host organisms. Additionally, a literature review of polyenes and non-polyene hemolytic metabolites produced by Streptomyces is presented.

Effect of Enterobacter cloacae toxin on immune cells isolated from Leukemia patients

Toxin extract affects Neutrophils and macrophages, which are phagocytic cells. A total of (180) samples, (50) urine and (130) peripheral blood have been obtained from leukemia patients referred to Medical city/ Baghdad Teaching Hospital/ Hematology center; all patients enrolled in this study were diagnosed by the physician according to clinical presentation and laboratory findings as leukemic patients. Investigate the role of Enterobacter cloacae toxins on phagocytic activity/THP-1cells and epithelial line/HBL-100 cells. THP-1 and HBL-100 cells have been kept in RPMI-1640 that have been supplemented by (10%) of the fetal bovine serum (100µg/mL) of the streptomycin and 100units/mL of the penicillin. The cells have been passaged with the use of the Trypsin-EDTA that has been re-seeded at a confluence of 80% twice every week, and then it has been incubated afterward at a temperature of (37C°). The results of toxin extract from Enterobacter cloacae revealed that (22) fraction/toxins were taken from (11) bacterial samples; these toxins were separated by gel electrophoresis for protein. (18) samples were positive results for gel electrophoresis of protein according to molecular weight: (13.3 KD for α-hemolysin), (70.5 KD for thiol), (75 KD for enterotoxin). This study demonstrates the cytotoxic activity of E. cloacae toxin by using tissue culture through their effect on suppressing the growth of "THP-1 cells" and HBL-100 cells". Keywords. Tissue culture; Toxin; THP-1 cells; HBL-100 cells; Enterobacter cloacae; Leukemia patients.

Hemolytic potential of bioaerosol-derived Aspergillus, Penicillium and Talaromyces mould isolates

Aspergillus, Penicillium and Talaromyces species are frequently cited as contaminants of various substrata and are often associated with indoor environments. The main purpose of this study was to assess the potential pathogenicity of aerosol-derived fungi from Aspergillus, Penicillium and Talaromyces genera, isolated in the rooms for con?servation of cultural heritage artefacts, via estimating hemolytic activity. Hemolysis was detected in 20.58% of tested isolates at 37?C (11.76% partial and 8.82% complete) and 64.71% at 25?C (38.24% partial and 26.47% complete). The majority of isolates that caused ? hemolysis led to the significant oxidation of hemoglobin iron with methemoglobin content in blood agar medium, higher than 80%. Aspergillus melleus was the only tested fungi that caused formation of ferry hemoglobin after the incubation at 25?C. Obtained I values (index of activity for hemolytic exoenzymes) for ? hemolysis were in range of from 0.13 to 0.60 for 37?C, while for the temperature of 25?C values were in range of from 0.08 to 0.50. The same values for ? hemolysis were in range of from 0.03 to 0.08 (37?C), i.e. 0.06 to 0.49 (25?C). Monitoring of pathogenic airborne fungi in indoor environments and estimation of their virulence is essential for the adequate assessment of human health risks.

Improving the Stability of Red Blood Cells in Rainbow Trout (Oncorhynchus mykiss) and Herring (Clupea harengus): Potential Solutions for Post-mortem Fish Handling to Minimize Lipid Oxidation

This study aimed at limiting hemolysis of fish red blood cells (RBCs) as a strategy to limit hemoglobin (Hb)-induced lipid oxidation during post-mortem handling and processing. Effects of varying temperature, salinity, and mechanical impact were studied using washed resuspended RBCs (wr-RBCs) and whole blood (WB) from rainbow trout (Oncorhynchus mykiss) and herring (Clupea harengus). The wr-RBCs were most stable avoiding mechanical stress, keeping isotonic conditions (0.9–1.3% NaCl) and low temperature 0–6 °C, with predicted minimum at 2.5 °C. When compared at the same salinity, it was found that hemolysis was more pronounced in herring than trout wr-RBCs. Furthermore, WB was more stable than wr-RBCs, showing protecting the effects of blood plasma. Studying individual plasma components, stabilizing effects were found from glucose, proteins, and ascorbic acid. This study indicates that small adjustments in the early handling and processing of fish such as changing salinity of storage and rinsing solutions could minimize Hb contamination of the fish muscle and thereby improve quality.

Phenotypes Associated with Pathogenicity: Their Expression in Arctic Fungal Isolates

Around 85% of the environments on Earth are permanently or seasonally colder than 5 °C. Among those, the poles constitute unique biomes, which harbor a broad variety of microbial life, including an abundance of fungi. Many fungi have an outstanding ability to withstand extreme conditions and play vital ecosystem roles of decomposers as well as obligate or facultative symbionts of many other organisms. Due to their dispersal capabilities, microorganisms from cryosphere samples can be distributed around the world. Such dispersal involves both species with undefined pathogenicity and potentially pathogenic strains. Here we describe the isolation of fungal species from pristine Arctic locations in Greenland and Svalbard and the testing of the expression of characteristics usually associated with pathogenic species, such as growth at 37 °C, hemolytic ability, and susceptibility to antifungal agents. A total of 320 fungal isolates were obtained, and 24 of the most abundant and representative species were further analyzed. Species known as emerging pathogens, like Aureobasidium melanogenum, Naganishia albida, and Rhodotorula mucilaginosa, were able to grow at 37 °C, showed beta-hemolytic activity, and were intrinsically resistant to commonly used antifungals such as azoles and echinocandins. Antifungal resistance screening revealed a low susceptibility to voriconazole in N. albida and Penicillium spp. and to fluconazole in Glaciozyma watsonii and Glaciozyma-related taxon.

Proteomic analysis of the Heliothis virescens ascovirus 3i (HvAV-3i) virion

Ascoviruses are enveloped, circular, double-stranded DNA viruses that can effectively control the appetite of lepidopteran larvae, thereby reducing the consequent damage and economic losses to crops. In this study, the virion of a sequenced Heliothis virescens ascovirus 3i (HvAV-3i) strain was used to perform proteomic analysis using both in-gel and in-solution digestion. A total of 81 viral proteins, of which 67 were associated with the virions, were identified in the proteome of HvAV-3i virions. Among these proteins, 23 with annotated functions were associated with DNA/RNA metabolism/transcription, virion assembly, sugar and lipid metabolism, signalling, cellular homoeostasis and cell lysis. Twenty-one viral membrane proteins were also identified. Some of the minor 'virion' proteins identified may be non-virion contaminants of viral proteins synthesized during replication, identified by more recent and highly sensitive methods. The extensive identification of the ascoviral proteome will establish a foundation for further investigation of ascoviral replication and infection.

Pathogenic adaptations of Colletotrichum fungi revealed by genome wide gene family evolutionary analyses

The fungal genus Colletotrichum contains hemibiotrophic phytopathogens being highly variable in host and tissue specificities. We sequenced a C. fructicola genome (1104–7) derived from an isolate of apple in China and compared it with the reference genome (Nara_gc5) derived from an isolate of strawberry in Japan. Mauve alignment and BlastN search identified 0.62 Mb lineage-specific (LS) genomic regions in 1104–7 with a length criterion of 10 kb. Genes located within LS regions evolved more dynamically, and a strongly elevated proportion of genes were closely related to non-Colletotrichum sequences. Two LS regions, containing nine genes in total, showed features of fungus-to-fungus horizontal transfer supported by both gene order collinearity and gene phylogeny patterns. We further compared the gene content variations among 13 Colletotrichum and 11 non-Colletotrichum genomes by gene function annotation, OrthoMCL grouping and CAFE analysis. The results provided a global evolutionary picture of Colletotrichum gene families, and identified a number of strong duplication/loss events at key phylogenetic nodes, such as the contraction of the detoxification-related RTA1 family in the monocot-specializing graminicola complex and the expansions of several ammonia production-related families in the fruit-infecting gloeosporioides complex. We have also identified the acquirement of a RbsD/FucU fucose transporter from bacterium by the Colletotrichum ancestor. In sum, this study summarized the pathogenic evolutionary features of Colletotrichum fungi at multiple taxonomic levels and highlights the concept that the pathogenic successes of Colletotrichum fungi require shared as well as lineage-specific virulence factors.

Aegerolysins: Lipid-binding proteins with versatile functions

Proteins of the aegerolysin family span many kingdoms of life. They are relatively widely distributed in bacteria and fungi, but also appear in plants, protozoa and insects. Despite being produced in abundance in cells at specific developmental stages and present in secretomes, only a few aegerolysins have been studied in detail. In particular, their organism-specific physiological roles are intriguing. Here, we review published findings to date on the distribution, molecular interactions and biological activities of this family of structurally and functionally versatile proteins, the aegerolysins.

Fungal aegerolysin-like proteins: distribution, activities, and applications

The aegerolysin protein family (from aegerolysin of the mushroom Agrocybe aegerita) comprises proteins of ∼15-20 kDa from various eukaryotic and bacterial taxa. Aegerolysins are inconsistently distributed among fungal species, and variable numbers of homologs have been reported for species within the same genus. As such noncore proteins, without a member of a protein family in each of the sequenced fungi, they can give insight into different species-specific processes. Some aegerolysins have been reported to be hemolytically active against mammalian erythrocytes. However, some function as bi-component proteins that have membrane activity in concert with another protein that contains a membrane attack complex/perforin domain. The function of most of aegerolysins is unknown, although some have been suggested to have a role in development of the organism. Potential biotechnological applications of aegerolysins are already evident, despite the limited scientific knowledge available at present. Some mushroom aegerolysins, for example, can be used as markers to detect and label specific membrane lipids. Others can be used as biomarkers of fungal exposure, where their genes can serve as targets for detection of fungi and their progression during infectious diseases. Antibodies against aegerolysins can also be raised as immuno-diagnostic tools. Aegerolysins have been shown to serve as a species determination tool for fungal phytopathogen isolates in terms of some closely related species, where commonly used internal transcribed spacer barcoding has failed. Moreover, strong promoters that regulate aegerolysin genes can promote secretion of heterologous proteins from fungi and have been successfully applied in simultaneous multi-gene expression techniques.

Biological activities of organic extracts of four Aureobasidium pullulans varieties isolated from extreme marine and terrestrial habitats

We report on the screening for biological activities of organic extracts from seven strains that represent four varieties of the fungus Aureobasidium pullulans, that is A. pullulans var. melanogenum, A. pullulans var. pullulans, A. pullulans var. subglaciale and A. pullulans var. namibiae. We monitored haemolysis, cytotoxicity, antioxidant capacity and growth inhibition against three bacterial species. The haemolytic activity of A. pullulans var. pullulans EXF-150 strain was due to five different haemolytically active fractions. Extracts from all of the other varieties contained at least one haemolytically active fraction. Short-term exposure of cell lines to these haemolytically active organic extracts resulted in more than 95% cytotoxicity. Strong antioxidant capacity, corresponding to 163.88 μg ascorbic acid equivalent per gram of total solid, was measured in the organic extract of the strain EXF-3382, obtained from A. pullulans var. melanogenum, isolated from the deep sea. Organic extracts from selected varieties of A. pullulans exhibited weak antibacterial activities.

Transcriptome and proteome exploration to provide a resource for the study of Agrocybe aegerita

BACKGROUND

Agrocybe aegerita, the black poplar mushroom, has been highly valued as a functional food for its medicinal and nutritional benefits. Several bioactive extracts from A. aegerita have been found to exhibit antitumor and antioxidant activities. However, limited genetic resources for A. aegerita have hindered exploration of this species.

METHODOLOGY/PRINCIPAL FINDINGS

To facilitate the research on A. aegerita, we established a deep survey of the transcriptome and proteome of this mushroom. We applied high-throughput sequencing technology (Illumina) to sequence A. aegerita transcriptomes from mycelium and fruiting body. The raw clean reads were de novo assembled into a total of 36,134 expressed sequences tags (ESTs) with an average length of 663 bp. These ESTs were annotated and classified according to Gene Ontology (GO), Clusters of Orthologous Groups (COG), and Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathways. Gene expression profile analysis showed that 18,474 ESTs were differentially expressed, with 10,131 up-regulated in mycelium and 8,343 up-regulated in fruiting body. Putative genes involved in polysaccharide and steroid biosynthesis were identified from A. aegerita transcriptome, and these genes were differentially expressed at the two stages of A. aegerita. Based on one-dimensional gel electrophoresis (1-DGE) coupled with electrospray ionization liquid chromatography tandem MS (LC-ESI-MS/MS), we identified a total of 309 non-redundant proteins. And many metabolic enzymes involved in glycolysis were identified in the protein database.

CONCLUSIONS/SIGNIFICANCE

This is the first study on transcriptome and proteome analyses of A. aegerita. The data in this study serve as a resource of A. aegerita transcripts and proteins, and offer clues to the applications of this mushroom in nutrition, pharmacy and industry.

Fungal hemolysins

Hemolysins are a class of proteins defined by their ability to lyse red cells but have been described to exhibit pleiotropic functions. These proteins have been extensively studied in bacteria and more recently in fungi. Within the last decade, a number of studies have characterized fungal hemolysins and revealed a fascinating yet diverse group of proteins. The purpose of this review is to provide a synopsis of the known fungal hemolysins with an emphasis on those belonging to the aegerolysin protein family. New insight and perspective into fungal hemolysins in biotechnology and health are additionally presented.

Development of monoclonal antibodies to recombinant terrelysin and characterization of expression in Aspergillus terreus

Aspergillus terreus is an emerging pathogen that mostly affects immunocompromised patients, causing infections that are often difficult to manage therapeutically. Current diagnostic strategies are limited to the detection of fungal growth using radiological methods or biopsy, which often does not enable species-specific identification. There is thus a critical need for diagnostic techniques to enable early and specific identification of the causative agent. In this study, we describe monoclonal antibodies (mAbs) developed to a previously described recombinant form of the haemolysin terrelysin. Sixteen hybridomas of various IgG isotypes were generated to the recombinant protein, of which seven demonstrated reactivity to the native protein in hyphal extracts. Cross-reactivity analysis using hyphal extracts from 29 fungal species, including 12 Aspergillus species and five strains of A. terreus, showed that three mAbs (13G10, 15B5 and 10G4) were A. terreus-specific. Epitope analysis demonstrated mAbs 13G10 and 10G4 recognize the same epitope, PSNEFE, while mAb 15B5 recognizes the epitope LYEGQFHS. Time-course studies showed that terrelysin expression was highest during early hyphal growth and dramatically decreased after mycelial expansion. Immunolocalization studies demonstrated that terrelysin was not only localized within the cytoplasm of hyphae but appeared to be more abundant at the hyphal tip. These findings were confirmed in cultures grown at room temperature as well as at 37 °C. Additionally, terrelysin was detected in the supernatant of A. terreus cultures. These observations suggest that terrelysin may be a candidate biomarker for A. terreus infection.

Production and characterization of IgM monoclonal antibodies against hyphal antigens of Stachybotrys species

Stachybotrys is a hydrophilic fungal genus that is well known for its ability to colonize water-damaged building materials in indoor environments. Personal exposure to Stachybotrys chartarum allergens, mycotoxins, cytolytic peptides, and other immunostimulatory macromolecules has been proposed to exacerbate respiratory morbidity. To date, advances in Stachybotrys detection have focused on the identification of unique biomarkers that can be detected in human serum; however, the availability of immunodiagnostic reagents to Stachybotrys species have been limited. In this study, we report the initial characterization of monoclonal antibodies (MAbs) against a semi-purified cytolytic S. chlorohalonata preparation (cScp) derived from hyphae. BALB/c mice were immunized with cScp and hybridomas were screened against the cScp using an antigen-mediated indirect ELISA. Eight immunoglobulin M MAbs were produced and four were specifically identified in the capture ELISA to react with the cScp. Cross-reactivity of the MAbs was tested against crude hyphal extracts derived from 15 Stachybotrys isolates representing nine Stachybotrys species as well as 39 other environmentally abundant fungi using a capture ELISA. MAb reactivity to spore and hyphal antigens was also tested by a capture ELISA and by fluorescent halogen immunoassay (fHIA). ELISA analysis demonstrated that all MAbs strongly reacted with extracts of S. chartarum but not with extracts of 39 other fungi. However, four MAbs showed cross-reactivity to the phylogenetically related genus Memnoniella. fHIA analysis confirmed that greatest MAb reactivity was ultrastructurally localized in hyphae and phialides. The results of this study further demonstrate the feasibility of specific MAb-based immunoassays for the detection of S. chartarum.

RahU: an inducible and functionally pleiotropic protein in Pseudomonas aeruginosa modulates innate immunity and inflammation in host cells

The aim of this study was to define the functional role of a recently identified RahU protein from Pseudomonas aeruginosa in macrophages and its role in bacterial defense. Recombinant (r)-RahU had no significant effect on cell apoptosis or cell viability in human monocytic THP-1 cells. Gene expression array of murine macrophage cells (RAW 264.7) stimulated with LPS showed modulation of common transcripts (by r-RahU and predisone) involved in inflammation. Functional cellular analysis showed RAW cells incubated with r-RahU at 1.0-10 μg/ml (0.06-0.6 μM) inhibited accumulation of nitric oxide (NO) in the presence of LPS by 10-50%. The IC(50) of r-RahU (0.6 μM) was distinct from the known inhibitors of NO production: prednisone (50 μM) and L-NMMA (100 μM). r-RahU also significantly inhibited chemotactic activity of THP-1 cells toward CCL2 or chemotactic supernatants from apoptotic T-cells. These reports show previously unknown pleiotropic properties of RahU in modulating both microbial physiology and host innate immunity.

Characterization of recombinant terrelysin, a hemolysin of Aspergillus terreus

Fungal hemolysins are potential virulence factors. Some fungal hemolysins belong to the aegerolysin protein family that includes cytolysins capable of lysing erythrocytes and other cells. Here, we describe a hemolysin from Aspergillus terreus called terrelysin. We used the genome sequence database to identify the terrelysin sequence based on homology with other known aegerolysins. Aspergillus terreus mRNA was isolated, transcribed to cDNA and the open reading frame for terrelysin amplified by PCR using specific primers. Using the pASK-IBA6 cloning vector, we produced recombinant terrelysin (rTerrelysin) as a fusion product in Escherichia coli. The recombinant protein was purified and using MALDI-TOF MS determined to have a mass of 16,428 Da. Circular dichroism analysis suggests the secondary structure of the protein to be predominantly β-sheet. Results from thermal denaturation of rTerrelysin show that the protein maintained the β-sheet confirmation up to 65°C. Polyclonal antibody to rTerrelysin recognized a protein of approximately 16.5 kDa in mycelial extracts from A. terreus.

The biocontaminants and complexity of damp indoor spaces: more than what meets the eyes

Nine types of biocontaminants in damp indoor environments from microbial growth are discussed: (1) indicator molds; (2) Gram negative and positive bacteria; (3) microbial particulates; (4) mycotoxins; (5) volatile organic compounds, both microbial (MVOCs) and non-microbial (VOCs); (6) proteins; (7) galactomannans; (8) 1-3-β-D-glucans (glucans) and (9) lipopolysaccharides (LPS — endotoxins). When mold species exceed those outdoors contamination is deduced. Gram negative bacterial endotoxins, LPS in indoor environments, synergize with mycotoxins. The gram positive Bacillus species, Actinomycetes (Streptomyces, Nocardia and Mycobacterium), produce exotoxins. The Actinomycetes are associated with hypersensitivity pneumonitis, lung and invasive infections. Mycobacterial mycobacterium infections not from M. tuberculosis are increasing in immunocompetent individuals. In animal models, LPS enhance the toxicity of roridin A, satratoxins G and aflatoxin B1 to damage the olfactory epithelium, tract and bulbs (roridin A, satratoxin G) and liver (aflatoxin B1). Aflatoxin B1 and probably trichothecenes are transported along the olfactory tract to the temporal lobe. Co-cultured Streptomyces californicus and Stachybotrys chartarum produce a cytotoxin similar to doxorubicin and actinomycin D (chemotherapeutic agents). Trichothecenes, aflatoxins, gliotoxin and other mycotoxins are found in dust, bulk samples, air and ventilation systems of infested buildings. Macrocyclic trichothecenes are present in airborne particles <2 μm. Trichothecenes and stachylysin are present in the sera of individuals exposed to S. chartarum in contaminated indoor environments. Haemolysins are produced by S. chartarum, Memnoniella echinata and several species of Aspergillus and Penicillium. Galactomannans, glucans and LPS are upper and lower respiratory tract irritants. Gliotoxin, an immunosuppressive mycotoxin, was identified in the lung secretions and sera of cancer patients with aspergillosis produced by A. fumigatus, A. terreus, A. niger and A. flavus.

Hemolysin chrysolysin from Penicillium chrysogenum promotes inflammatory response

Some strains of Penicillium chrysogenum produce a proteinaceous hemolysin, chrysolysinTM, when incubated on sheep's blood agar at 37 degrees C but not at 23 degrees C. However, 92% (11/12) of the indoor air isolates produced hemolysis but only 43% (3/7) of the non-indoor air isolates did so. Chrysolysin is an aggregating protein composed of approximately 2kDa monomers, contains one cysteine amino acid, and has an isoelectric point of 4.85. Treatment of murine macrophage cell line RAW 264.7 with purified chrysolysin caused statistically significant (T-test, p < 0.05) increased production of macrophage inflammatory protein-2 (MIP-2) in a dose dependent manner after 6 h treatment. This suggests that chrysolysin might act to promote the host's inflammatory response after P. chrysogenum exposures.