TPCK

Laceyella sacchari strain BK‐TM, isolated from the Salt Lake of Chott Ech Chergui ( El‐Bayadh, Algeria ), was found to produce an extracellular thermostable serine protease (SPLS). The highest level of protease activity detected after 6 days of incubation at 50°C was 44,600 U/mL. SPLS was purified after heat treatment for 5 min at 80°C, subjected to ammonium sulfate fractionation (80%), and Sephacryl S‐200 High Resolution (HR) column purification. The purified enzyme consists of a single protein with an approximate molecular weight of 29 kDa as determined by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE). The sequence of the 24 N‐terminal residues of SPLS was highly similar to those of Thermoactinomycetaceae proteases. Furthermore, the complete inhibition by phenylmethanesulfonyl fluoride (PMSF) and diiodopropyl fluorophosphates (DIFP) indicates that SPLS is a member of the serine protease family. The enzyme exhibits optimal activity at pH 9 and 70°C. The thermostability of SPLS increased when 1 mM of Ca 2+ was added, with a half‐life of 8 h at 80°C and 3 h at 90°C. Its catalytic activity was superior to that of SPSM from Streptomyces mutabilis strain TN‐X30, PREFERENZ P300, and PROTEASE Type XIV. Interestingly, SPLS demonstrated high compatibility with ISIS and Maison Det, serving as solid and liquid laundry detergents, respectively. Furthermore, performance evaluations revealed that SPLS effectively removes blood stains. Overall, SPLS exhibited interesting biochemical features, suggesting its potential use as a cleaning bio‐additive in detergent formulations.

An arabinan polysaccharide of low molecular weight (SC-S50, 3.2 KDa) and a structurally-related high molecular weight arabinan (SC-P50, 66 KDa) were isolated from Sida cordifolia root. NMR spectroscopy revealed the two polysaccharides were structurally similar consisting of three motifs, the main one being an α-L-arabinofuranose disaccharide (A-(1 → 5)-D) in the linear backbone; the A unit is further substituted at O-2 and O-3 positions by α-L-arabinofuranose. The two minority motifs also consist of α-1 → 5 linked L-arabinofuranose disaccharide, but in contrast, the A unit is replaced by the E or F unit, which is substituted by α-L-arabinofuranose only at the O-2 or O-3 position. SC-S50 did not activate macrophages cells in vitro, but in contrast, SC-P50 potently stimulated nitric oxide production in RAW264.7 macrophages (EC50: 7.92 μg/mL). SC-P50 significantly increased pinocytosis (phagocytosis), cell proliferation and cytokine secretion (IL-2, IL-6, TNF-α, IL-8), with minimal cytotoxicity. SC-P50 was then screened in 12 human primary cell-systems simulating various human tissue and disease characteristics. In 10 of these cell systems SC-P50 increased the production of IL-8. Mechanism-of-action studies unpicked the receptors, intracellular signalling and metabolic responses underlying SC-P50's immunomodulatory actions. SC-P50 is a novel immunomodulatory plant-derived polysaccharide which should be evaluated for its ability to prevent/treat infection.