The fungal insect pathogen Beauveria bassiana produces a range of insecticidal metabolites and enzymes, including chitinases and proteases, which may assist the disease progression. The enzymes often play a predominant role in the pathogenicity pathway and both chitinases and proteases have previously been shown to be important in host infection. Spray application of supernatants of B. bassiana broth cultures of an isolate from New Zealand caused significant mortality in the green peach aphid, Myzus persicae, within 24 h, demonstrating an apparent contact toxicity. Three-day-old broth cultures were the most effective, with less insect mortality seen using six-day-old broth. However, aphicidal activity increased again when treating aphids with seven-day-old broth. Cultures grew substantially better and produced more potent aphicidal cultures when cultured in media with an initial pH above 5.5. Chitinase was produced a day earlier than the serine protease Pr1, but the peak production periods of these enzymes did not correlate with the aphicidal activities of three- or six-day-old cultures. Cultures treated with EDTA or heated to inactivate the enzymes still showed strong insecticidal activity. Neither beauvericin nor bassianolide, two known insecticidal metabolites, were detected in the supernatants. Therefore the key aphicidal components of B. bassiana cultures were not associated with chitinase nor Pr1 and are yet to be identified.
A cultivar of fruiting bodies of Ophiocordyceps sinensis (FBOS; OCS02) was analyzed for nutrients, bioactive compounds, and heavy metal content to showcase its potential as a competitive, sustainable, and safe alternative to wild types and other cultivars. A previous 28-day subacute toxicity study showed that doses up to 1 g · kg-1 did not cause any adverse effects in Sprague-Dawley rats. The OCS02 cultivar contained large amounts of cordycepin, polysaccharides, and essential and semi-essential amino acids (0.66, 482.80, 99.02, and 101.04 g · kg-1, respectively) compared with levels reported in wild types and in cultivated mycelia. β-1,3/1,6-glucan content was considerably high at 342.50 g · kg-1. The potassium level (5.14 g kg-1) tied in well with the low sodium content (0.121 g · kg-1)-6 times lower than amounts in wild types. We found no detectable levels of heavy metals such as lead, arsenic, cadmium, and mercury. The major amino acids found in FBOS (0CS02 cultivar) were arginine, lysine, serine, and threonine at 45.20, 20.30, 18.60, and 18.20 g · kg-1, respectively. The cultivated FBOS (OCS02 cultivar) is a comparable alternative to wild-type and other cultivated strains of O. sinensis. It has potential as a nutraceutical to meet market demand.
A lectin gene from the Tiger Milk Mushroom Lignosus rhinocerus TM02® was successfully cloned and expressed via vector pET28a in Escherichia coli BL21(DE3). The recombinant lectin, Rhinocelectin, with a predicted molecular mass of 22.8 kDa, was overexpressed in water-soluble form without signal peptide and purified via native affinity chromatography Ni-NTA agarose. Blast protein analysis indicated the lectin to be homologous to jacalin-related plant lectin. In its native form, Rhinocelectin exists as a homo-tetramer predicted with four chains of identical proteins consisting of 11 beta-sheet structures with only one alpha-helix structure. The antiproliferative activity of the Rhinocelectin against human cancer cell lines was concentration dependent and selective. The IC50 values against triple negative breast cancer cell lines MDA-MB-231 and breast cancer MCF-7 are 36.52 ± 13.55 μg mL-1 and 53.11 ± 22.30 μg mL-1 , respectively. Rhinocelectin is only mildly cytotoxic against the corresponding human nontumorigenic breast cell line 184B5 with IC50 value at 142.19 ± 36.34 μg mL-1 . The IC50 against human lung cancer cell line A549 cells is 46.14 ± 7.42 μg mL-1 while against nontumorigenic lung cell line NL20 is 41.33 ± 7.43 μg mL-1 . The standard anticancer drug, Doxorubicin exhibited IC50 values mostly below 1 μg mL-1 for the cell lines tested. Flow cytometry analysis showed the treated breast cancer cells were arrested at G0/G1 phase and apoptosis induced. Rhinocelectin agglutinated rat and rabbit erythrocytes at a minimal concentration of 3.125 μg mL-1 and 6.250 μg mL-1 , respectively.