Mushroom lectins: current status and future perspectives

Effects of Cold Plasma Pretreatment on the Synthesis of Polysaccharide from Pleurotus ostreatus

Fungal polysaccharides have attracted wide attention because of their medical pharmaceutical and health care value. So far, many efforts have been made in strain improvement to produce polysaccharides on a large scale at low cost. Here, a novel cold plasma-induced strain improvement technology was employed to pretreat Pleurotus ostreatus CGMCC 5.374 by radio-frequency (RF) low-vacuum cold plasma (LVCP) for the purpose of obtaining a high-yield polysaccharide strain. The optimum pretreatment conditions including discharge power, treatment time, and working pressure were determined by single factor and orthogonal experiment in succession. Furthermore, transcriptome analysis was conducted to study the effects of RF-LVCP on cell metabolism and proliferation. Results showed that under the optimal condition of discharge power of 130 W, treatment time of 25 s and working pressure of 140 Pa, polysaccharide content in mycelium was increased by 3.16% after 6 days in comparison to the original strain. Transcriptome analysis showed that RF-LVCP is helpful for specific gene transcription profiles, Gene Ontology (GO) and KEGG pathways, of which the differentially expressed genes (DEGs) were mainly involve with the up-regulation of polysaccharide transport, physiology, synthesis and metabolism, as well as the down-regulation of polysaccharide hydrolysis and macromolecular degradation.

Structural, extraction and safety aspects of novel alternative proteins from different sources

With rapid population growth and continued environmental degradation, it is no longer sustainable to rely on conventional proteins to meet human requirements. This has prompted the search for novel alternative protein sources of greater sustainability. Currently, proteins of non-conventional origin have been developed, with such alternative protein sources including plants, insects, algae, and even bacteria and fungi. Most of these protein sources have a high protein content, along with a balanced amino acid composition, and are regarded as healthy and nutritious sources of protein. While these novel alternative proteins have excellent nutritional, research on their structure are still at a preliminary stage, particularly so for insects, algae, bacteria, and fungi. Therefore, this review provides a comprehensive overview of promising novel alternative proteins developed in recent years with a focus on their nutrition, sustainability, classification, and structure. In addition, methods of extraction and potential safety factors for these proteins are summarized.

Integrating machine learning and electrochemistry to develop a glucose biosensor assembled with Ganoderma applanatum lectin

Fungal lectins have enormous biotechnological potential, but limited knowledge about their biochemical and biophysical features prevents their proper use. Herein, we report an innovative alternative to use Ganoderma applanatum lectin (GAL) as a glucose biorecognition element, after identifying the ideal electroanalytical conditions by machine learning studies performed with a homologous agglutinin from the same macrofungus. The research revealed that GAL has moderate resistance to pH (4-8) and temperature (20-60 °C) variations, but its hemagglutinating activity (376.5 HU mg^-1 GAL at 20 °C) was better conserved under physiological conditions. Integrating electrochemical data and semi-empirical molecular modeling, biocompatible and electrostatically favorable conditions were found to immobilize the lectin on Prussian blue-modified glassy carbon electrode, after thermal activation of the metal-complex film. The glucose dose-response relationship obtained with the developed biosensor, defined as GAL/ta-PB/GCE, showed a typical Hill equation correlation, suggesting electrodic interactions represented by a sigmoidal mathematical function. GAL/ta-PB/GCE achieved remarkable electroanalytical performance, with emphasis on the detection limit (10.2 pM) and sensitivity (0.012 µA µM^-1cm^-2). The biosensor was successfully used to quantify glucose in pharmaceutical formulations, reiterating that the association of theoretical and experimental information drives important advances in bioelectrochemical studies.

Recent advance in quality preservation of non-thermal preservation technology of fresh mushroom: a review

Fresh mushrooms have a long history of cultivation and consumption, but high postharvest losses are a concern in the commercial production of mushrooms worldwide. Thermal dehydration is widely used in the preservation of commercial mushrooms, but the flavor and taste of mushrooms are significantly altered after dehydration. Non-thermal preservation technology, which effectively maintains the characteristics of mushrooms, is a viable alternative to thermal dehydration. The objective of this review was to critically assess the factors affecting fresh mushroom quality after preservation is remarkable, with the ultimate goal of developing and promoting non-thermal preservation technology for preserving fresh mushroom quality, effectively extending the shelf life of fresh mushrooms. The factors influencing the quality degradation process of fresh mushrooms discussed herein include the internal factors associated with the mushroom itself and the external factors associated with the storage environment. We present a comprehensive discussion of the effects of different non-thermal preservation technologies on the quality and shelf life of fresh mushrooms. To prevent quality loss and extend the shelf life after postharvest, hybrid methods, such as physical or chemical techniques combined with chemical techniques, and novel nonthermal technologies are highly recommended.

Agaricus bisporus Wild Mushroom Extract as Lectin Source for Engineering a Lactose Photoelectrochemical Biosensor

Agaricus bisporus mushroom biomass contains a lectin, ABL, with remarkable specificity for lactose biorecognition; in this work, this feature was explored to develop a photoelectrochemical biosensor. The high lectin activity found in saline extracts of this macrofungus (640 HU mL^-1), even at critical pH values (4-10) and temperatures (20-100 °C), allowed its direct use as an ABL source. Theoretical and experimental evidence revealed favorable electrostatic and biocompatible conditions to immobilize ABL on a poly(methylene blue)/fluorine-doped tin oxide-coated glass platform, giving rise to the ABL/PMB/FTO biosensor. The conducting polymer added further photoactivity to the device, allowing the identification of lectin-carbohydrate interactions with even greater sensitivity. The dose-response curves studied by electrochemical impedance spectroscopy showed a sigmoidal profile that was well-fitted by Hill's equation, expanding the working dynamic range (15-540 nmol L^-1 lactose; 20.2 pmol L^-1 detection limit) and avoiding undesirable sample dilution or preconcentration procedures. Under the optimized photoelectrochemical conditions, the ABL/PMB/FTO biosensor showed remarkable signal stability, accuracy, specificity, and selectivity to analyze lactose in commercial food products. This research raises interest in ABL-based biosensors and the added value of the crude Agaricus bisporus extract toward the development of greener and more sustainable biotechnological approaches.

Elucidating Heavy Metals Concentration and Distribution in Wild Edible Morels and the Associated Soil at Different Altitudinal Zones of Pakistan: a Health Risk Implications Study

This study evaluates macro-nutrient (MN) and prevailing heavy metal (HM) concentrations in wild edible morels (WEM) species viz., Morchella crassipes, Morchella pulchella, and Morchella eohespera and the associated soil that were collected from different altitudinal zones (Azad Kashmir, Murree, Swat, and Skardu) of Pakistan. A special emphasis on potential health risk analysis for HM in WEM consumption was also explored. In general, MN concentration in fruiting bodies and their associated soil samples were in the following order: potassium (K) > magnesium (Mg) > calcium (Ca) > sodium (Na) and Ca > Mg > K > Na, respectively. The concentration for HM in WEM ranged between 20.0 and 78.0 mg/kg, 1.09 and 22.1 mg/kg, 2.1 and 22.1 mg/kg, 0.26 and 13.1 mg/kg, 0.43 and 9.1 mg/kg, 1.07 and 7.0 mg/kg, 1.01 and 5.4 mg/kg, and BDL and 3.1 mg/kg for zinc (Zn), copper (Cu), nickel (Ni), manganese (Mn), cobalt (Co), chromium (Cr), lead (Pb), and cadmium (Cd), respectively, and those in underlying soil samples, lowest and highest HM concentration were recorded for Zn (33.7-113.6 mg/kg), Cu (13.0-40.8 mg/kg), Ni (3.1-23.0 mg/kg), Pb (1.3-22.0 mg/kg), Co (2.9-5.6 mg/kg), Cr (2.7-11.1 mg/kg), Mn (2.0-7.1 mg/kg), and Cd (1.1 mg/kg 7.6). Although, Cd, Pb, and Zn concentrations in some of the WEM samples and Cd in the soil had exceeded the permissible limits set by different organizations. The greater accumulation/or transfer potential for Zn, Co, Ni, and Cu were recorded in WEM from their associated soil. The health risk index (HRI) for HM in all assessed samples of WEM was < 1, predicting no risk to the consuming population. Furthermore, the correlation analyses depicted that the power of hydrogen (pH), low organic matter contents, and sandy texture are likely to be responsible for HM transfer to the lower pool of soil. But the increasing concentration of HM in WEM warrants threats and suggests further monitoring and future policy plan and implementation to avoid the potential health risks via its regular consumption.

Purification and characterization of a synergistic bioactive lectin from Pleurotus flabellatus (PFL-L) with potent antibacterial and in-vitro radical scavenging activity

Lectin is a carbohydrate-binding protein, which exhibits a plethora of biological properties such as antimicrobial, antifungal, and anticancer activities. In the present study, lectin, with an antibacterial and antioxidant potential, was purified from the oyster mushroom Pleurotus flabellatus. The P. flabellatus Lectin (PFL-L) was purified by using a DEAE - cellulose anion exchange chromatography followed by gel-filtration chromatography. The PFL-L was characterized by CD, HPLC, and MALDI-TOF/MS. The purity of PFL-L increased to 62.40% with the recovery of hemagglutinating activity (HA) by 12.12%. On SDS - PAGE, the PFL-L gave a single band of 18 kDa. PFL-L, consisting of d-galactose, exhibits a strong hemagglutinating activity. It was stable at pH (6.0-7.5) and temperature (10-20 °C) in addition to having extensive hemagglutinating activity. PFL-L enhanced the HA with the use of different metal ions namely Mg²⁺, Ca^2+, and Fe²⁺. The study of bacterial growth inhibition led to the inference that the PFL-L was more potent against gram-negative bacteria. PFL-L showed the highest radical scavenging activity for the DPPH assay at 100 μg/mL (89.9 ± 2.53%). The highest antioxidant activities with IC₅₀ values (for DPPH assay) of 53.96 μg/mL were determined for PFL-L and the present study shows that lectin from P. flabellatus manifested distinctive character and potentially exploitable activities.

Cordyceps militaris: An Overview of Its Chemical Constituents in Relation to Biological Activity

Cordyceps spp. mushrooms have a long tradition of use as a natural raw material in Asian ethnomedicine because of their adaptogenic, tonic effects and their ability to reduce fatigue and stimulate the immune system in humans. This review aims to present the chemical composition and medicinal properties of Cordyceps militaris fruiting bodies and mycelium, as well as mycelium from in vitro cultures. The analytical results of the composition of C. militaris grown in culture media show the bioactive components such as cordycepin, polysaccharides, γ-aminobutyric acid (GABA), ergothioneine and others described in the review. To summarize, based on the presence of several bioactive compounds that contribute to biological activity, C. militaris mushrooms definitely deserve to be considered as functional foods and also have great potential for medicinal use. Recent scientific reports indicate the potential of cordycepin in antiviral activity, particularly against COVID-19.

Fungi and Algae as Sources of Medicinal and Other Biologically Active Compounds: A Review

Many species of fungi including lichenized fungi (lichens) and algae have the ability to biosynthesize biologically active compounds. They produce, among others, polysaccharides with anticancer and immunostimulatory properties: (1) Background: This paper presents the characteristics of the most important bioactive compounds produced by fungi and algae; (2) Methods: Based on the example of the selected species of mushrooms, lichens and algae, the therapeutic properties of the secondary metabolites that they produce and the possibilities of their use are presented; (3) Results: The importance of fungi, especially large-fruited mushrooms, lichens and algae, in nature and human life is discussed, in particular, with regard to their use in the pharmaceutical industry and their nutritional value; (4) Conclusions: The natural organisms, such as fungi, lichenized fungi and algae, could be used as supplementary medicine, in the form of pharmaceutical preparations and food sources. Further advanced studies are required on the pharmacological properties and bioactive compounds of these organisms.

Narrative Review: Bioactive Potential of Various Mushrooms as the Treasure of Versatile Therapeutic Natural Product

Mushrooms have remained an eternal part of traditional cuisines due to their beneficial health potential and have long been recognized as a folk medicine for their broad spectrum of nutraceuticals, as well as therapeutic and prophylactic uses. Nowadays, they have been extensively investigated to explain the chemical nature and mechanisms of action of their biomedicine and nutraceuticals capacity. Mushrooms belong to the astounding dominion of Fungi and are known as a macrofungus. Significant health benefits of mushrooms, including antiviral, antibacterial, anti-parasitic, antifungal, wound healing, anticancer, immunomodulating, antioxidant, radical scavenging, detoxification, hepatoprotective cardiovascular, anti-hypercholesterolemia, and anti-diabetic effects, etc., have been reported around the globe and have attracted significant interests of its further exploration in commercial sectors. They can function as functional foods, help in the treatment and therapeutic interventions of sub-optimal health states, and prevent some consequences of life-threatening diseases. Mushrooms mainly contained low and high molecular weight polysaccharides, fatty acids, lectins, and glucans responsible for their therapeutic action. Due to the large varieties of mushrooms present, it becomes challenging to identify chemical components present in them and their beneficial action. This article highlights such therapeutic activities with their active ingredients for mushrooms.

Application of K-Means Clustering Algorithm to Commercial Parameters of Pleurotus spp. Cultivated on Representative Agricultural Wastes from Province of Guayas

Data of the commercial parameters of Pleurotus ostreatus and Pleurotus djamor were analyzed using the data mining technique: K-means clustering algorithm. The parameters evaluated were: biological efficiency, crop yield ratio, productivity rate, nutritional composition, antioxidant and antimicrobial activities in the production of fruit bodies of 50 strains of Pleurotus ostreatus and 50 strains of Pleurotus djamor, cultivated on the most representative agricultural wastes from the province of Guayas: 80% sugarcane bagasse and 20% wheat straw (M1), and 60% wheat straw and 40% sugarcane bagasse (M2). The database of the parameters obtained in experimental procedures was grouped into three clusters, providing a visualization of the strains with a higher relation to each parameter (vector) measured.

Lectins purified from medicinal and edible mushrooms: Insights into their antiviral activity against pathogenic viruses

For thousands of years, fungi have been a valuable and promising source of therapeutic agents for treatment of various diseases. Mushroom is a macrofungus which has been cultivated worldwide for its nutritional value and medicinal applications. Several bioactive molecules were extracted from mushroom such as polysaccharides, lectins and terpenoids. Lectins are carbohydrate-binding proteins with non-immunologic origin. Lectins were classified according to their structure, origin and sugar specificity. This protein has different binding specificity with surface glycan moiety which determines its activity and therapeutic applications. A wide range of medicinal activities such as antitumor, antiviral, antimicrobial, immunomodulatory and antidiabetic were reported from sugar-binding proteins. However, glycan-binding protein from mushroom is not well explored as antiviral agent. The discovery of novel antiviral agents is a public health emergency to overcome the current pandemic and be ready for the upcoming viral pandemics. The mechanism of action of lectin against viruses targets numerous steps in viral life cycle such as viral attachment, entry and replication. This review described the history, classification, purification techniques, structure-function relationship and different therapeutic applications of mushroom lectin. In addition, we focus on the antiviral activity, purification and physicochemical characteristics of some mushroom lectins.

Genus Parkia: Phytochemical, Medicinal Uses, and Pharmacological Properties

The genus Parkia (Fabaceae, Subfamily, Mimosoideae) comprises about 34 species of mostly evergreen trees widely distributed across neotropics, Asia, and Africa. This review aims to provide an overview of the current status of the species from the genus Parkia in terms of its relationship between its phytochemistry and medical uses. Comprehensive information on Parkia species was retrieved from electronic databases, which were Web of Science, ScienceDirect, PubMed, and Google Scholar. This review identified nine species from genus Parkia with properties of medicinal use. They are used traditionally to treat several ailments, such as diabetes, diarrhea, wounds, hypertension, cough, chronic piles, conjunctivitis, and measles. The most common species studied are P. biglobosa, P. speciosa, P. javanica, P. bicolor, P. biglandulosa, P. filicoidea, and P. clappertoniana. A considerable number of secondary metabolites, such as terpenoids, phenolic acids, flavonoids (aglycone and glycosides), and numerous volatile compounds have been identified in this genus, which are responsible for their diverse pharmacological activities. Their extracts, pure compounds and seed lectins have been reported for their anticancer, antimicrobial, antihypertensive, antiulcer, antidiabetic, anti-inflammatory, antioxidant, antimalarial, hepatoprotective, and antidiarrheal activities. The information gathered in this review might be of help for future studies in terms of the current knowledge on the link between the phytochemical components and medicinal uses. This could facilitate more discoveries on its potentials particularly in the pharmacological characteristics and potential to be developed into modern medicines.

The use of cyanobacterial metabolites as natural medical and biotechnological tools: review article

Cyanobacteria are photosynthetic, Gram-negative bacteria that are considered one of the most morphologically diverse groups of prokaryotes with a chief role in the global nutrient cycle as they fixed gaseous carbon dioxide and nitrogen to organic materials. Cyanobacteria have significant adaptability to survive in harsh conditions due to they have different metabolic pathways with unique compounds, effective defensive mechanisms, and wide distribution in different habitats. Besides, they are successfully used to face different challenges in several fields, including industry, aquaculture, agriculture, food, dairy products, pollution control, bioenergy, and pharmaceutics. Analysis of 680 publications revealed that nearly 1630 cyanobacterial molecules belong to different families have a wide range of applications in several fields, including cosmetology, agriculture, pharmacology (immunosuppressant, anticancer, antibacterial, antiprotozoal, antifungal, anti-inflammatory, antimalarial, anticoagulant, anti-tuberculosis, antitumor, and antiviral activities) and food industry. In this review, we nearly mentioned 92 examples of cyanobacterial molecules that are considered the most relevant effects related to anti-inflammatory, antioxidant, antimicrobial, antiviral, and anticancer activities as well as their roles that can be used in various biotechnological fields. These cyanobacterial products might be promising candidates for fighting various diseases and can be used in managing viral and microbial infections.Communicated by Ramaswamy H. Sarma.

Current Understanding of the Structure and Function of Fungal Immunomodulatory Proteins

Fungal immunomodulatory proteins (FIPs) are a group of proteins found in fungi, which are extensively studied for their immunomodulatory activity. Currently, more than 38 types of FIPs have been described. Based on their conserved structure and protein identity, FIPs can be classified into five subgroups: Fve-type FIPs (Pfam PF09259), Cerato-type FIPs (Pfam PF07249), PCP-like FIPs, TFP-like FIPs, and unclassified FIPs. Among the five subgroups, Fve-type FIPs are the most studied for their hemagglutinating, immunomodulating, and anti-cancer properties. In general, these small proteins consist of 110–125 amino acids, with a molecular weight of ~13 kDa. The other four subgroups are relatively less studied, but also show a noticeable influence on immune cells. In this review, we summarized the protein modifications, 3-dimensional structures and bioactivities of all types of FIPs. Moreover, structure-function relationship of FIPs has been discussed, including relationship between carbohydrate binding module and hemagglutination, correlation of oligomerization and cytokine induction, relevance of glycosylation and lymphocyte activation. This summary and discussion may help gain comprehensive understanding of FIPs' working mechanisms and scope future studies.

Structure and properties of the oyster mushroom (Pleurotus ostreatus) lectin

Pleurotus ostreatus Lectin (POL) is a 353 amino acid chain lectin that can be purified from the fruiting bodies of the very well-known and widely diffused edible oyster mushrooms (P. ostreatus). The lectin has been partially characterized by different groups and, although it was crystallized about 20 years ago, its 3D structure and the details of its interactions with carbohydrates are still unknown. This paper reports the 3D structure and ligand-binding properties of POL. We have determined the X-ray structure of the apo-protein purified from the fruiting bodies of the mushroom and that of the recombinant protein in complex with melibiose to a resolution of about 2 Å. The lectin is a homodimer in which the two polypeptide chains are linked by a disulfide bridge. A POL monomer is composed of two highly homologous β-jellyroll domains each of which containing a calcium-dependent carbohydrate-binding site. A high degree of sequence similarity is observed between the two carbohydrate-binding modules present in each monomer. The structure of the lectin in complex with melibiose reveals that a POL dimer has four calcium-dependent carbohydrate-binding sites. The interaction with sugars in solution has been characterized by isothermal titration calorimetry and saturation transfer difference NMR and it sheds new light on the molecular determinants of POL specificity. The lectin exhibits in vitro antiproliferative effects against human cancer cell lines and presents structural similarity with the prototype member of the CBM67 family, the noncatalytic domain of Streptomyces avermitilis α-rhamnosidase.

Heterologous expression and molecular binding properties of AofleA, a fucose-specific lectin from nematophagous fungus Arthrobotrys oligospora

Lectins are the primary recognition macromolecules for various types of fucosylation, a common eukaryotic post-translational modification. In this study, we report the heterologous expression and molecular binding properties of a fucose-specific lectin, AofleA, isolated from Arthrobotrys oligospora. This is the first reported fucose-specific lectin found in nematophagous fungi. The recombinant AofleA (r-AofleA) was expressed in Escherichia coli with high efficiency, yielding at least 500 mg of soluble and functional r-AofleA per liter of broth. Using hemagglutination inhibition assay and glycan microarray analysis, r-AofleA was found to be broadly specific for fucosylated glycans or oligosaccharides including Fucα(1-2), Fucα(1-3), Fucα(1-4) and Fucα(1-6) linkages, similar to Aleuria aurantia lectin (AAL). Frontal affinity chromatography showed that r-AofleA has high affinity towards PA-L-fucose with an average K_d value of 15 nM. These findings provide a basis for improved understanding of the structure and functions of AofleA during recognition and capture of prey nematodes by nematophagous fungus A. oligospora.

Lectin from Laetiporus sulphureus effectively inhibits angiogenesis and tumor development in the zebrafish xenograft models of colorectal carcinoma and melanoma

In spite of extensive usage of Laetiporus sulphureus (sulphur polypore) in traditional European and Asian ethno-medicine for centuries, its anticancer therapeutic potential and toxicity profile remained explored in animal models. Herein, using zebrafish (Danio rerio), as a preclinical animal model, we demonstrated that L. sulphureus lectin (LSL) and ethanol extract (LSE) are non-toxic at high doses up to 400-500 μg/mL, while they effectively inhibited angiogenesis and cancer development at much lower doses. Lectin showed 74-fold higher anti-angiogenic potency than the extract, and even 378-fold higher therapeutic potential than sunitinib-malate, cardiotoxic and myelosupressive anti-angiogenic drug of clinical relevance. Using wound healing and MTT assays, we proved LSL's strong antimigratory effect and selective endothelial cytotoxicity in relation to lung fibroblasts. In addition, employing the zebrafish xenograft models, we demonstrated that LSL almost completely reduced growth, neovascularization and metastasis of human colorectal carcinoma and mouse melanoma. Even more, LSL exerted 8-fold higher potency towards colorectal carcinoma than melanoma, showing markedly higher activity than cisplatin, while LSE failed to express any anticancer activity. Accompanied with non-toxic response, including neutropenia and inflammation, the results of this study strongly imply that LSL could be used as safe adjuvant in chemotherapy against colorectal carcinoma and melanoma.

Edible mushrooms as a novel protein source for functional foods

Fast demographic growth has led to increasing interest in low-cost alternative protein sources to meet population needs.

Structure-function and application of plant lectins in disease biology and immunity

Lectins are proteins with a high degree of stereospecificity to recognize various sugar structures and form reversible linkages upon interaction with glyco-conjugate complexes. These are abundantly found in plants, animals and many other species and are known to agglutinate various blood groups of erythrocytes. Further, due to the unique carbohydrate recognition property, lectins have been extensively used in many biological functions that make use of protein-carbohydrate recognition like detection, isolation and characterization of glycoconjugates, histochemistry of cells and tissues, tumor cell recognition and many more. In this review, we have summarized the immunomodulatory effects of plant lectins and their effects against diseases, including antimicrobial action. We found that many plant lectins mediate its microbicidal activity by triggering host immune responses that result in the release of several cytokines followed by activation of effector mechanism. Moreover, certain lectins also enhance the phagocytic activity of macrophages during microbial infections. Lectins along with heat killed microbes can act as vaccine to provide long term protection from deadly microbes. Hence, lectin based therapy can be used as a better substitute to fight microbial diseases efficiently in future.

Ganoderma proteins and their potential applications in cosmetics

Ganoderma have been regarded as a traditional source of natural bioactive compounds for centuries and have recently been exploited for potential components in the cosmetics industry. Besides Ganoderma polysaccharides and triterpenes, multiple proteins have been found in Ganoderma. With the in-depth study of these proteins, various pharmacological functions of Ganoderma have become important in the discovery and development of new products. In the review, we summarized and discussed the kinds and characteristics of Ganoderma proteins, especially on fungal immunomodulatory proteins (FIPs) which can be potentially developed into cosmeceuticals or nutricosmetics and are a suitable target for production using established biotechnological methods. Furthermore, we discuss their pharmacological activities of the proteins with a focus on their pharmacological functions related to cosmetics, such as antioxidant activity, inhibition of melanin, antibacterial activity, and regulation of inflammatory mediators. Numerous other questions also are addressed before the proteins can be widely accepted and used as cosmetic additives.

Purification of a potent mitogenic homodimeric Penicillium griseoroseum lectin and its characterisation

Penicillium griseoroseum lectin was 80-fold purified by successive DEAE Sepharose anion exchange and Sephadex G-100 gel permeation chromatography. P. griseoroseum lectin exhibited haemagglutination activity towards protease-treated rabbit erythrocytes. It showed specificity towards various carbohydrates such as d-mannose, N-acetyl-d-glucosamine, mucins, and so forth. P. griseoroseum lectin was found as a glycoprotein with glycan content of 4.33%. Purified P. griseoroseum lectin is homodimeric having a molecular mass of 57 kDa with subunit molecular mass of 28.6 kDa. Haemagglutination activity of purified P. griseoroseum lectin was completely stable from 25°C to 35°C at a pH range of 6-7.5. Lectin activity was not influenced by divalent metal ions and denaturants. P. griseoroseum lectin manifested mitogenicity towards mice splenocytes and activity reached a peak at 75 μg/ml of lectin concentration. P. griseoroseum lectin in microgram concentrations stimulated proliferation of mice splenocytes. Thus, P. griseoroseum lectin exhibits potential mitogenicity, which can be exploited for further biomedical applications.

An Inulin-Specific Lectin with Anti-HIV-1 Reverse Transcriptase, Antiproliferative, and Mitogenic Activities from the Edible Mushroom Agaricus bitorquis

A novel lectin (ABL) was purified from the dried fruiting bodies of Agaricus bitorquis. An efficient 3-step purification protocol involved two consecutive steps of ion exchange chromatography on Q-Sepharose and SP-Sepharose and gel filtration by FPLC on Superdex 75. ABL is a monomeric protein with the molecular mass of 27.6 kDa, which is different from other lectins from genus Agaricus. Its N-terminal amino acid sequence is EYTISIRVYQTNPKGFNRPV which is unique and sharing considerably high similarity of other mushroom lectins. The hemagglutinating activity of the lectin was inhibited by inulin. Based on hemagglutination tests, ABL prefers rabbit, human type A, and AB erythrocytes to human type B and O erythrocytes. The lectin inhibits the activity of HIV-1 reverse transcriptase and the proliferation of leukemia cell (L1210) with an IC₅₀ value of 4.69 and 4.97 μM, respectively. Furthermore, ABL demonstrates the highest mitogenic activity with a response of 24177.7 ± 940.6 [³H-methyl] thymidine counts per minute (CPM) at a concentration of 0.91 μM.

Overview of the Structure⁻Function Relationships of Mannose-Specific Lectins from Plants, Algae and Fungi

To date, a number of mannose-binding lectins have been isolated and characterized from plants and fungi. These proteins are composed of different structural scaffold structures which harbor a single or multiple carbohydrate-binding sites involved in the specific recognition of mannose-containing glycans. Generally, the mannose-binding site consists of a small, central, carbohydrate-binding pocket responsible for the "broad sugar-binding specificity" toward a single mannose molecule, surrounded by a more extended binding area responsible for the specific recognition of larger mannose-containing N-glycan chains. Accordingly, the mannose-binding specificity of the so-called mannose-binding lectins towards complex mannose-containing N-glycans depends largely on the topography of their mannose-binding site(s). This structure⁻function relationship introduces a high degree of specificity in the apparently homogeneous group of mannose-binding lectins, with respect to the specific recognition of high-mannose and complex N-glycans. Because of the high specificity towards mannose these lectins are valuable tools for deciphering and characterizing the complex mannose-containing glycans that decorate both normal and transformed cells, e.g., the altered high-mannose N-glycans that often occur at the surface of various cancer cells.

Lectins from red algae and their biomedical potential

Lectins are unique proteins or glycoproteins of non-immune origin that bind specifically to carbohydrates. They recognise and interact reversibly to either free carbohydrates or glycoconjugates, without modifying their structure. Lectins are highly diverse and widely distributed in nature and have been extensively reported from various red algae species. Numerous red algae species have been reported to possess lectins having carbohydrate specificity towards complex glycoproteins or high-mannose N-glycans. These lectin-glycan interactions further trigger many biochemical responses which lead to their extensive use as valuable tools in biomedical research. Thus, owing to their exceptional glycan recognition property, red algae lectins are potential candidate for inhibition of various viral diseases. Hence, the present report integrates existing information on the red algae lectins, their carbohydrate specificity, and characteristics of purified lectins. Further, the review also reports the current state of research into their anti-viral activity against various enveloped viruses such as HIV, hepatitis, influenza, encephalitis, coronavirus and herpes simplex virus and other biomedical activities such as anti-cancer, anti-microbial, anti-inflammatory, anti-nociceptive and acaricidal activities.

Mushrooms: from nutrition to mycoremediation

Mushrooms are well known as important food items. The uses of mushrooms in the cuisine are manifolds and are being utilized for thousands of years in both Oriental and Occidental cultures. Medicinal properties of mushrooms show an immense potential as drugs for the treatment of various diseases as they are rich in a great variety of phytochemicals. In this review, we attempted to encompass the recent knowledge and scientific advancement about mushrooms and their utilization as food or curative properties, along with their natural ability to accumulate (heavy) metals/radionuclides, which leads to an important aspect of bioremediation. However, accumulation of heavy metals and radionuclides from natural or anthropogenic sources also involves potential nutritional hazards upon consumption. These hazards have been pointed out in this review incorporating a selection of the most recently published literature.

Lectins from Mycelia of Basidiomycetes

Lectins are proteins of a nonimmunoglobulin nature that are capable of specific recognition of and reversible binding to the carbohydrate moieties of complex carbohydrates, without altering the covalent structure of any of the recognized glycosyl ligands. They have a broad range of biological activities important for the functioning of the cell and the whole organism and, owing to the high specificity of reversible binding to carbohydrates, are valuable tools used widely in biology and medicine. Lectins can be produced by many living organisms, including basidiomycetes. Whereas lectins from the fruit bodies of basidiomycetes have been studied sufficiently well, mycelial lectins remain relatively unexplored. Here, we review and comparatively analyze what is currently known about lectins isolated from the vegetative mycelium of macrobasidiomycetes, including their localization, properties, and carbohydrate specificities. Particular attention is given to the physiological role of mycelial lectins in fungal growth and development.

Cyanobacterial lectins characteristics and their role as antiviral agents

Lectins are ubiquitous proteins/glycoproteins of non-immune origin that bind reversibly to carbohydrates in non-covalent and highly specific manner. These lectin-glycan interactions could be exploited for establishment of novel therapeutics, targeting the adherence stage of viruses and thus helpful in eliminating wide spread viral infections. Here the review focuses on the haemagglutination activity, carbohydrate specificity and characteristics of cyanobacterial lectins. Cyanobacterial lectins exhibiting high specificity towards mannose or complex glycans have potential role as anti-viral agents. Prospective role of cyanobacterial lectins in targeting various diseases of worldwide concern such as HIV, hepatitis, herpes, influenza and ebola viruses has been discussed extensively. The review also lays emphasis on recent studies involving structural analysis of glycan-lectin interactions which in turn influence their mechanism of action. Altogether, the promising approach of these cyanobacterial lectins provides insight into their use as antiviral agents.

Polyporus squamosus Lectin 1a (PSL1a) Exhibits Cytotoxicity in Mammalian Cells by Disruption of Focal Adhesions, Inhibition of Protein Synthesis and Induction of Apoptosis

PSL1a is a lectin from the mushroom Polyporus squamosus that binds to sialylated glycans and glycoconjugates with high specificity and selectivity. In addition to its N-terminal carbohydrate-binding domain, PSL1a possesses a Ca²⁺-dependent proteolytic activity in the C-terminal domain. In the present study, we demonstrate that PSL1a has cytotoxic effects on mammalian cancer cells, and we show that the cytotoxicity is dependent on the cysteine protease activity. PSL1a treatment leads to cell rounding and detachment from the substratum, concomitant with disruption of vinculin complexes in focal adhesions. We also demonstrate that PSL1a inhibits protein synthesis and induces apoptosis in HeLa cells, in a time- and concentration-dependent manner.

A Jacalin-Related Lectin Regulated the Formation of Aerial Mycelium and Fruiting Body in Flammulina velutipes

Flammulina velutipes, one of the most popular mushroom species in the world, has been recognized as a useful model system to study the biochemical and physiological aspects of the formation and elongation of fruit body. However, few reports have been published on the regulation of fruiting body formation in F. velutipes at the molecular level. In this study, a jacalin-related lectin gene from F. velutipes was characterized. The phylogenetic tree revealed that Fv-JRL1 clustered with other basidiomycete jacalin-like lectins. Moreover, the transcriptional pattern of the Fv-JRL1 gene in different developmental stages of F. velutipes implied that Fv-JRL1 could be important for formation of fruit body. Additionally, RNA interference (RNAi) and overexpression analyses provided powerful evidence that the lectin gene Fv-JRL1 from F. velutipes plays important roles in fruiting body formation.

In vivo immunomodulatory effect of the lectin from edible mushroom Agaricus bisporus

Lectins are glycan-binding proteins that are resistant to digestion in the gastrointestinal tract and enter intact to blood circulation. The aim of this study was to evaluate the influence of edible mushroom Agaricus bisporus lectin (ABL) on innate and adaptive immune responses as well as its effect in two different experimental pathologies that involve the immune system. ABL inhibited in vitro nitric oxide (NO) production by mouse peritoneal macrophages in response to the pro-inflammatory stimuli lipopolysaccharides (LPS). However, it did not modify the activity of arginase, showing that while ABL downregulates M1 activation, it does not affect M2 activation. ABL also inhibited mononuclear cell proliferation in response to mitogen Con A, or in a mixed lymphocyte reaction. During the in vivo studies, oral administration of ABL to BALB/c mice induced a marked inhibition of NO production by peritoneal macrophages after LPS stimuli. The influence of ABL on tumor growth was studied in BALB/c mice receiving daily oral doses of ABL and implanted with CT26 tumor cells. ABL treatment induced significantly higher rate of tumor growth when compared with control mice. On the other hand, oral ABL administration in Wistar rats induced a marked diminution of the incidence of the disease and the severity of the clinical signs of experimental autoimmune encephalomyelitis. We can conclude that ABL has an in vivo immunomodulatory effect reducing the innate and adaptive responses. This food lectin shows potential therapeutic application on control of inflammatory autoimmune pathologies.

Lectin activity in mycelial extracts of Fusarium species

Lectins are non-immunogenic carbohydrate-recognizing proteins that bind to glycoproteins, glycolipids, or polysaccharides with high affinity and exhibit remarkable ability to agglutinate erythrocytes and other cells. In the present study, ten Fusarium species previously not explored for lectins were screened for the presence of lectin activity. Mycelial extracts of F. fujikuroi, F. beomiformii, F. begoniae, F. nisikadoi, F. anthophilum, F. incarnatum, and F. tabacinum manifested agglutination of rabbit erythrocytes. Neuraminidase treatment of rabbit erythrocytes increased lectin titers of F. nisikadoi and F. tabacinum extracts, whereas the protease treatment resulted in a significant decline in agglutination by most of the lectins. Results of hapten inhibition studies demonstrated unique carbohydrate specificity of Fusarium lectins toward O-acetyl sialic acids. Activity of the majority of Fusarium lectins exhibited binding affinity to d-ribose, l-fucose, d-glucose, l-arabinose, d-mannitol, d-galactosamine hydrochloride, d-galacturonic acid, N-acetyl-d-galactosamine, N-acetyl-neuraminic acid, 2-deoxy-d-ribose, fetuin, asialofetuin, and bovine submaxillary mucin. Melibiose and N-glycolyl neuraminic acid did not inhibit the activity of any of the Fusarium lectins. Mycelial extracts of F. begoniae, F. nisikadoi, F. anthophilum, and F. incarnatum interacted with most of the carbohydrates tested. F. fujikuroi and F. anthophilum extracts displayed strong interaction with starch. The expression of lectin activity as a function of culture age was investigated. Most species displayed lectin activity on the 7th day of cultivation, and it varied with progressing of culture age.

Uptake of Marasmius oreades agglutinin disrupts integrin-dependent cell adhesion

BACKGROUND

Fruiting body lectins have been proposed to act as effector proteins in the defense of fungi against parasites and predators. The Marasmius oreades agglutinin (MOA) is a lectin from the fairy ring mushroom with specificity for Galα1-3Gal containing carbohydrates. This lectin is composed of an N-terminal carbohydrate-binding domain and a C-terminal dimerization domain. The dimerization domain of MOA shows in addition calcium-dependent cysteine protease activity, similar to the calpain family.

METHODS

Cell detachment assay, cell viability assay, immunofluorescence, live cell imaging and Western blot using MDCKII cell line.

RESULTS

In this study, we demonstrate in MDCKII cells that after internalization, MOA protease activity induces profound physiological cellular responses, like cytoskeleton rearrangement, cell detachment and cell death. These changes are preceded by a decrease in FAK phosphorylation and an internalization and degradation of β1-integrin, consistent with a disruption of integrin-dependent cell adhesion signaling. Once internalized, MOA accumulates in late endosomal compartments.

CONCLUSION

Our results suggest a possible toxic mechanism of MOA, which consists of disturbing the cell adhesion and the cell viability.

GENERAL SIGNIFICANCE

After being ingested by a predator, MOA might exert a protective role by diminishing host cell integrity.