Kinetic and thermodynamic characteristic of Aspergillus awamori EM66 levansucrase.

This study is a new trial aimed to solve levansucrase high cost and levan associated problems during the purification process. Also, kinetic and thermodynamic study was done to compare between the partial pure (PP) and purified forms (PF). Within this context, Aspergillus awamori EM66 levansucrase was produced constitutively (5.44 U.mL-1) using rice straw as the sole medium component. The enzyme was partially purified and was eluted as single protein after two purification steps. Its molecular weight was determined to be 44.5 KDa. The optimum temperature recorded 40 °C for both enzyme forms. While, the purification process lowering the enzyme pH from 5.2 to 4.0. The NaCl concentrations (0.5-3.0 M) pointed to the halophilic nature of the enzyme. The PP form retained about 76% of its original activity after 1 h at 55 °C while the other retained about 57% after 45 min. at the same temperature. The kinetic parameters Km and Vmax concluded that the PF was more efficient than the PP. The thermodynamic parameters such as Ea, Ed, T1/2, D-value, also, ∆G*, ∆H* and ∆ S* for activation recorded that the PP had higher stability than the PF.

First novel synthesis of triazole thioglycosides as ribavirin analogues.

This study reports a novel and efficient method for the synthesis of the first reported novel class of triazole thioglycosides. These series of compounds were designed through the reaction of potassium cyanocarbonimidodithioate 2 with hydrazine derivatives 3a-d in EtOH at room temperature to give the corresponding potassium 5-amino-1H-1,2,4-triazole-3-thiolates 4a-d. The latter compounds were treated with tetra-O-acetyl-α-D-glucopyranosyl bromide 6a and tetra-O-acetyl-α-D-galactopyranosyl bromide 6b in DMF at room temperature to give in high yields the corresponding triazole thioglycosides 7a-h. Treatment of triazole salts 4a-d with hydrochloric acid afforded the corresponding 3-mercaptotriazoles 5a-d. Compounds 5a-d were then reacted with bromoperacetylated sugars 6a,b in sodium hydride-DMF at ambient temperature to afford the thioglycosyl compounds 7a-h. Ammonolysis of the triazole thioglycosides 7a-h afforded the corresponding free thioglycosides 8a-h. The scope and limitation of the method is demonstrated. The structure of the reaction products was confirmed on the basis of their elemental analysis and spectral data (IR, 1H NMR, MS and 13C NMR).

Computer-aided identification of novel anticancer compounds with a possible dual HER1/HER2 inhibition mechanism.

HER1 and HER2 are frequently overexpressed in human tumors where they drive cellular proliferation. For this reason they are considered important targets in anticancer therapy with dual HER1/HER2 inhibitors being recently approved and marketed. In this paper we report the identification of a series of compounds with anticancer activity by a combined virtual screening approach on the kinase domains of HER1 and HER2. 6 hit compounds that present a sub- or low-micromolar activity in two cell-based assays, were initially identified and a subsequent design cycle led to the synthesis of a compound with nanomolar activity in the cell-based assays.

Toxicological studies for some agricultural waste extracts on mosquito larvae and experimental animals.

OBJECTIVE: To evaluate some agricultural waste extracts as insecticide and their effects on enzyme activities in liver and kidney of male mice. METHODS: The insecticidal activity of five tested compounds (one crude extract and 4 waste compounds) was bioassay against the 3rd instars of the Culex pipiens (Cx. pipiens) larvae in the laboratory. The LC50 values of eucalyptol, apricot kernel, Rice bran, corn, black liquor and white liquor are 91.45, 1 166.1, 1 203.3, 21 449.65, 4 025.78 and 6 343.18 ppm, respectively. Selection of the compounds for the subsequent studies was not only dependent on LC50 values but also on the persistence of these wastes products on large scale. RESULTS: White and black liquor did not produce any gross effect at 200 mg/Kg body weight. No apparent toxic symptoms were observed in tested animals during the whole period of the experiment which run out for 14 days. No statistically significance was observed in the enzyme cholinesterase activity, the activities of liver enzymes and kidney function in treated mice with black and white liquors. While, no and slight inhibition was observed after the 2 weeks of treatment period with deltamethrin and fenitrothion reached to about 24% in plasma cholinesterase enzyme activity. Significantly increase in the activities of liver enzymes and kidney function in treated mice with deltamethrin and fenitrothion. CONCLUSIONS: Black liquor can be used efficiently to control Cx. pipiens larvae under laboratory condition. Environmental problem caused by rice straw can be solved by converting the waste material to beneficial natural selective insecticide.

Synthesis and antioxidant activity of new pyridines containing gallate moieties.

Pyridines containing the galloyl moiety have been prepared utilizing 4-acetyl pyrogallol. In addition, fused pyridines were synthesized from the obtained pyridines via further chemical transformations. The results indicated that compound 4a showed stronger DPPH scavenging activity than the other compounds, and the scavenging effect decreased in the following order 4a > t-BHQ > 2a > 2b > 3a > 3b > 4b. Accordingly, other antioxidant assays were conducted for 4a. The results suggested that compound 4a could be a good antioxidant candidate. The absence of mortality of rats receiving 5000 mg/kg body weight of 4a as single oral dose may indicate that it could be a safe antioxidant and may be used for further studies.

Synthesis, biological and medicinal significance of S-glycosido-thieno[2,3-d]-pyrimidines as new anti-inflammatory and analgesic agents.

Several 2-thioglycosides were prepared. Glycosylation of 2-thioxo-thieno[2,3-d]-pyrimidines 5a,b with 1-bromo-2,3,5-tri-O-acetyl-alpha-d-arabinofuranosyle 7, 2,3,4,6-tetra-O-acetyl-alpha-d-glucopyranosyl and galacto-pyranosyl bromide 8a,b gave the protected beta-d-nuclosides 10a,b and 13a-d in high yields, which were transformed to deacetylated derivatives 14a,b and 15a-d. The structures of the compounds were elucidated by spectral and elemental analysis. Anti-inflammatory and Analgesic activities screening of the new compounds (at a dose of 100 mg/kg body weight) utilizing in vivo acute carrageenan-induced paw oedema standard method exhibited that the deacetylated derivatives 14a,b and 15a-d possess highly promising activities.