The overview and perspectives of biosensors and Mycobacterium tuberculosis: A systematic review.

Tuberculosis (TB) is referred to as a "consumption" or phthisis, which has been a fatal human disease for thousands of years. Mycobacterium tuberculosis (M. tb) might have been responsible for the death of more humans than any other bacterial pathogens. Therefore, the rapid diagnosis of this bacterial infection plays a pivotal role in the timely and appropriate treatment of the patients, as well as the prevention of disease spread. More than 98% of TB cases are reported in developing countries, and due to the lack of well-equipped and specialized diagnostic laboratories, development of effective diagnostic methods based on biosensors is essential for this bacterium. In this review, original articles published in English were retrieved from multiple databases, such as PubMed, Scopus, Google Scholar, Science Direct, and Cochrane Library during January 2010-October 2019. In addition, the reference lists of the articles were also searched. Among 109 electronically searched citations, 42 articles met the inclusion criteria. The highest potential and wide usage of biosensors for the diagnosis of M. tb and its drug resistance belonged to DNA electrochemical biosensors (isoniazid and rifampin strains). Use of biosensors is expanding for the detection of resistant strains of anti-TB antibiotics with high sensitivity and accuracy, while the speed of these sensory methods is considered essential as well. Furthermore, the lowest limit of detection (0.9 fg/ml) from an electrochemical DNA biosensor was based on graphene-modified iron-oxide chitosan hybrid deposited on fluorine tin oxide for the MPT64 antigen target. According to the results, the most common methods used for M. tb detection include acid-fast staining, cultivation, and polymerase chain reaction (PCR). Although molecular techniques (e.g., PCR and real-time PCR) are rapid and sensitive, they require sophisticated laboratory and apparatuses, as well as skilled personnel and expertise in the commentary of the results. Biosensors are fast, valid, and cost-efficient diagnostic method, and the improvement of their quality is of paramount importance in resource-constrained settings.

Rapid and label-free electrochemical DNA biosensor based on a facile one-step electrochemical synthesis of rGO-PPy-(L-Cys)-AuNPs nanocomposite for the HTLV-1 oligonucleotide detection.

Human T cell leukemia virus type 1 (HTLV-1) as the first human retrovirus is currently a serious endemic health challenge. Despite the use of assorted molecular or serological assays for HTLV-1 detection, there are several limitations due to the lack of a confirmatory test that may affect the accuracy of the results. Herein, a novel label-free biosensor for the detection of HTLV-1 Tax gene has been reported. An electrochemical facile ecofriendly synthesis method has been demonstrated based on a synthesis of nanocomposite of reduced graphene oxide, polypyrrole, and gold nanoparticles (rGO-PPy-(l-Cys)-AuNPs) deposited on the surface of screen-printed carbon electrode. Electrochemical techniques were used to characterize and study the electrochemical behavior of the rGO-PPy-(l-Cys)-AuNPs, which exhibited a stable reference peak at 0.21 V associated with hybridization forms by applying the differential pulse voltammetry. The designed DNA biosensor presented a wide linear range from 0.1 fM to 100 µM and a low detection limit of 20 atto-molar. The proposed biosensor presented in this study provides outstanding selectivity, sensitivity, repeatability, and reproducibility.

Anticancer potentiality and mode of action of low-carbohydrate proteins and peptides from mushrooms.

Severe side effects of chemotherapy as well as drug resistance highlight the ongoing need to discover novel natural bioactive compounds with anticancer potentiality. Mushroom-derived proteins are among the naturally occurring compounds that have been the subject of a body of research on their potentiality in cancer therapy. The greatest attention in relevant review articles has been paid to well-known mushroom-derived glycoproteins such as lectins and protein-bound polysaccharide complexes such as polysaccharide-K (PSK) or krestin and polysaccharopeptide (PSP), which contain substantial amounts of carbohydrates (50-90%). These complex compounds exert their anticancer activity mainly by binding to cell membranes leading to extrinsic (death receptor) apoptosis or intrinsic (mitochondrial) apoptotic pathways. However, several other research studies have reported pure, well-characterized, proteins or peptides from mushrooms, which are carbohydrate-free or have very low amounts of carbohydrate. These proteins may fall into four categories including fungal immunomodulatory proteins, ubiquitin-like proteins, enzymes, and unclassified proteins. Well-defined chemical structure, elucidated full amino acid or N-terminal sequences, purity, and having some distinct and specific pathways compared to glycoproteins have made these low-carbohydrate proteins attractive for cancer research. The aim of this review was therefore to improve the current understanding of mushroom-derived low-carbohydrate proteins and to consolidate the existing knowledge of the most promising mushroom species from which low-carbohydrate proteins have been derived, characterized, and examined for their anticancer activity. In addition, molecular targets and mechanisms of action of these proteins have been discussed. Key points • Mushroom-derived low-carbohydrate proteins lack or have low carbohydrate. • Low-carbohydrate proteins show potent anticancer activities in vitro and in vivo. • There are specific pathways for low-carbohydrate proteins to inhibit cancer cells.

Agronomic and environmental factors affecting cultivation of the winter mushroom or Enokitake: achievements and prospects.

The global interest in production of the winter mushroom or Enokitake (Flammulina filiformis previously known as Flammulina velutipes) is increasing owing to its nutritional and medicinally important bioactive compounds along with a marketable texture and flavor. This review presents the state of knowledge on achievements in solid-state cultivation and submerged cultures of Enokitake and how they are influenced by environmental factors and agronomic characteristics. A wide range of basic lignocellulosic substrates and supplementations have been reviewed in order to formulate an efficient and locally available substrate. Domestication of wild types of Enokitake and its economic and research implications are also discussed. Besides, the influence of environmental and agronomic factors on production and efficacy of the most important biologically active metabolites of Enokitake in both solid-state cultivation and submerged cultures has been discussed. Some of shortcomings of studies reporting cultivation of Enokitake are described and their contribution to future prospects is also discussed in this review.

Biosynthesis and antibiotic activity of silver nanoparticles using different sources: Glass industrial sewage-adapted Bacillus sp. and herbaceous Amaranthus sp.

Synergistic effects of metallic nanoparticles (NPs) with commonly used antibiotics have encouraged the exploration of novel biological entities, including bacteria and weed plants. The present study for the first time reports the capability of an extracellular fraction of Bacillus sp. isolated from effluents of a glass-manufacturing unit to biosynthesis silver nanoparticles (AgNPs) without hazardous materials. Besides, the biosynthesis of AgNPs using an aqueous extract of herbaceous weed plant (Amaranthus sp.), as a low-cost natural source, has been addressed in this study. Our findings confirmed the fabrication of microbial and plant-sourced AgNPs, being thoroughly characterized by UV-vis, transmission electron microscopy, X-ray diffraction, dynamic light scattering, energy dispersive X-ray spectroscopy, and zeta potential measurements. Further, biological activities of the plant- and bacterium-derived AgNPs were investigated against several pathogenic bacteria, in combination with streptomycin. The antibacterial effectiveness of the antibiotic coated with 400 µg/disk of AgNPs increased over 50% toward all the pathogenic bacteria. The data presented here demonstrate that both industrial wastewater-adapted Bacillus sp. and wild-growing Amaranthus sp. are efficient natural sources with excellent capabilities for creating biologically active AgNPs, which would be of considerable interest for circumventing bacterial resistance to current antibiotics.

Antibacterial Activity of Culinary-Medicinal Polypore Mushroom Lentinus tigrinus (Agaricomycetes).

Medicinal mushrooms belonging to Lentinus spp. exhibit significant antibacterial activities, but little attention has been paid to their efficacy against the food-borne pathogen, Bacillus cereus. The present study for the first time quantitatively evaluated the antibacterial activity of different extracts from fruiting bodies of a well-authenticated Iranian native strain of medicinal mushroom, Lentinus tigrinus, against Gram-positive spore-forming bacterium B. cereus. The findings revealed that the acetone extract inhibited the growth of B. cereus at concentrations as low as 31.25 µg/ML, while it had no effect against Escherichia coli and Staphylococcus aureus even at 10,000 µg/ML. The rest of the bacteria were also susceptible to the acetone extract at concentrations greater than 5 mg/ML. Antibacterial activities of the methanol-ethyl acetate extract and the hot water extract were significantly weaker than that of the acetone extract, which contained high amounts of total phenols (5.83 ± 0.08 mg GAE/g, dw), while Fourier transform infrared spectroscopy (FT-IR) confirmed the presence of functional groups, such as hydroxyl, carbonyl, amide, and amine. Further studies by scanning electron microscopy (SEM) confirmed obvious changes in the morphology of B. cereus in response to the acetone extract of L. tigrinus. This study may suggest that L. tigrinus could be a good natural source for isolating and purifying antibacterial compounds against B. cereus.

Interactive Effects of Selenium, Zinc, and Iron on the Uptake of Selenium in Mycelia of the Culinary-Medicinal Winter Mushroom Flammulina velutipes (Agaricomycetes).

The present study for the first time addressed whether the simultaneous presence of selenium, zinc and iron may have effects on the selenium uptake in the mycelia of the winter mushroom (also known as enoki), Flammulina velutipes. Response surface methodology was used to optimize concentrations of selenium, zinc and iron in the range of 0 to 120 mg L-1. The findings showed that application of selenium, zinc and iron (singly, in pairs, or triads) significantly enhanced the selenium accumulation in the mycelia. The highest amount of the selenium accumulation was observed when selenium (60 mg L-1) and zinc (120 mg L-1) were applied into submerged culture media, concurrently, leading to an 85-fold and 88-fold increase in the selenium content of the mycelia compared to that of the mycelia treated with selenium only and untreated mycelia, respectively. In addition, accumulation of selenium into the mycelia had no deteriorative effects on the mycelial biomass. The findings presented in this study may have implications for daily nutrition and industrial bioproduction of mushroom mycelia enriched with selenium.

Improvement and Characterization of Naturally Occurring Folate Compounds in Fruiting Bodies of Culinary-Medicinal Winter Mushroom, Flammulina velutipes (Agaricomycetes).

Edible mushrooms are among food sources containing natural folate compounds. However, little is known about how the content of folates in edible mushrooms may be improved. This study aimed to enrich Flammulina velutipes with higher levels of folates and to characterize patterns of the bioconversion of folates in the fruiting bodies. A convenient method was developed to treat a lignocellulosic substrate with synthetic folic acid. Folate compounds in the fruiting bodies grown in folic acid-treated substrates were evaluated relative to those in untreated substrates. Reverse phase high-performance liquid chromatography revealed different patterns of changes in levels of unsubstituted and substituted folates. While there was an approximately 15-fold and 8-fold increase in 5-formyl tetrahydrofolate and 5-methyl tetrahydrofolate, respectively, the most inconsistency was seen in the tetrahydrofolate content. There were also differences in the level of folate derivatives between commercial and native F. velutipes mushrooms. Since F. velutipes mushrooms can be consumed raw, the enriched mushrooms can be used as a dietary source to meet adult requirements for the daily uptake of natural folates.

Toxicity and Nutritional Assessment of Extracts of Medicinal Tiger Sawgill Mushroom, Lentinus tigrinus (Agaricomycetes), a Newly Domesticated in Iran.

Information on the biosafety of tiger sawgill mushroom, Lentinus tigrinus, is limited and controversial. In the present study, the toxicity of a native L. tigrinus strain was evaluated in both cell cultures and mice. In addition to proximate analysis, the amino acid composition and the substrate-dependent uptake of elements were also evaluated. The mushroom (dry weight) had 7.53 ± 0.11% ash, 4.23 ± 0.23% lipid, 13.4 ± 0.04% fiber, 74.84 ± 0.38% total carbohydrate, and 4.16 ± 0.08 (mg GAEs/g) total phenol. Lysine was found at the highest amount among the L-amino acids determined in the L. tigrinus soluble protein. Comparison of the elemental profile of L. tigrinus with that of the substrate demonstrated a great capacity for absorption of K, P, S, and Mg elements, while the Na uptake was low. Neither the substrate nor the mushroom contained toxic elements beyond the standards of the joint FAO/WHO. The viability of normal human and mouse-derived cells was not influenced by the extract up to 250 µg/mL, where 70% of cancerous PC3 and MCF-7 cells were killed. Selectivity index analysis suggested that the L. tigrinus extract was selective only against MCF-7 cells. The extract also did not affect mice treated orally or via i.p. injection, while i.v. injection caused some mortality in mice with an LD50 of 47.19 mg/mL. In conclusion, L. tigrinus may be considered a source of macronutrients and micronutrients with a selective anticancer activity, while it is much less likely to have detrimental effects on humans at low serving levels.

The Use of Microalgae for Coupling Wastewater Treatment With CO2 Biofixation.

Production and emission of CO2 from different sources have caused significant changes in the climate, which is the major concern related to global warming. Among other CO2 removal approaches, microalgae can efficiently remove CO2 through the rapid production of algal biomass. In addition, microalgae have the potential to be used in wastewater treatment. Although, wastewater treatment and CO2 removal by microalgae have been studied separately for a long time, there is no detailed information available on combining both processes. In this review article, microalgae-based CO2 biofixation, various microalgae cultivation systems,¯ and microalgae-derived wastewater treatment are separately discussed, followed by the concept of integration of CO2 biofixation process and wastewater treatment. In each section, details of energy efficiency and differences across microalgae species are also given.

Antioxidant capacity of several Iranian, wild and cultivated strains of the button mushroom.

The white button mushroom, Agaricus bisporus, is the most commonly grown mushroom in Iran; however, there is a significant shortage of research on its antioxidant activity and other medicinal properties. The aim of this study was to evaluate antioxidant capacity of the methanolic extracts from four cultivated strains and four Internal Transcribed Spacer (ITS)-identified, Iranian wild isolates of A. bisporus. Evaluations were made for total phenols, flavonoids and anthocyanins, and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity. Overall, results showed that all the wild isolates exhibited significantly lower DPPH-derived EC50, compared to the cultivated strains (p < 0.05). A relatively high relationship was observed between total phenols and flavonoids or anthocyanins (r(2) > 0.60). However, these constituents could not statistically differentiate the group of wild samples from the cultivated ones, and there was low correlation with the DPPH-derived EC50s (r(2) < 0.40). In conclusion, comparisons showed that wild isolate 4 and cultivated strains A15 and H1 had higher antioxidant capacity than the others (p < 0.05). This result identifies these mushrooms as good candidates for further investigation.

Antioxidant capacity of several Iranian, wild and cultivated strains of the button mushroom

The white button mushroom, Agaricus bisporus, is the most commonly grown mushroom in Iran; however, there is a significant shortage of research on its antioxidant activity and other medicinal properties. The aim of this study was to evaluate antioxidant capacity of the methanolic extracts from four cultivated strains and four Internal Transcribed Spacer (ITS)-identified, Iranian wild isolates of A. bisporus. Evaluations were made for total phenols, flavonoids and anthocyanins, and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity. Overall, results showed that all the wild isolates exhibited significantly lower DPPH-derived EC₅₀, compared to the cultivated strains (p < 0.05). A relatively high relationship was observed between total phenols and flavonoids or anthocyanins (r² > 0.60). However, these constituents could not statistically differentiate the group of wild samples from the cultivated ones, and there was low correlation with the DPPH-derived EC₅₀s (r² < 0.40). In conclusion, comparisons showed that wild isolate 4 and cultivated strains A15 and H1 had higher antioxidant capacity than the others (p < 0.05). This result identifies these mushrooms as good candidates for further investigation.