Investigating the effects of various additives on surface activity and emulsification index of biosurfactant resulting from broth media of Bacillus subtilis PTCC 1023

Surfactants are amphipathic molecules which reduce surface tension and are widely used in pharmaceutical, cosmetic and food industries. In the present study, the production of biosurfactant by Bacillus subtilis PTCC 1023 was studied. B. subtilis was grown in the nutrient broth medium and biosurfactant production was evaluated by measuring the surface tension and emulsification index (E24) each 24 h. The bacterium’s biosurfactant production was investigated in different status with variable factors such as incubation time, temperature, aeration rate and presence of several additives. Then the best fermentation condition was investigated for maximum biosurfactant production and finally biosurfactant identity was investigated using some chemical and spectroscopy methods. The maximum biosurfactant production by B. subtilis PTCC 1023 was obtained when it was grown in brain-heart broth medium containing FeSO4 (4×10-3 M), MnSO4 (1.3×10-3 M), starch (4%) and castor oil (4%) which incubated in a 300 rpm rotary shaker at 30°C for 24 h. Lipopepetide natures in this biosurfactant was confirmed by biochemical and spectroscopic methods

Investigation of cellular hydrophobicity and surface activity effects of biosynthesed biosurfactant from broth media of PTCC 1561

Biosurfactants as surface active molecules that are synthesized by microorganisms. These substances include many advantages in comparison with chemical surfactants. For instance they have lower toxicity, higher biodegradability, better environmental compatibility, higher foaming activity, and specific activity at extreme temperatures, pH ranges, and the ability to be synthesized from renewable feed stocksin. In this study, the production of biosurfactant, produced by PTCC 1561 was studied. This bactrium was grown in a nutrient broth medium and the production of biosurfactant was evaluated by the surface tension and emulisification index (E24), each 24 h. The production of biosurfactant was studied in different conditions, including time of incubation, temperature, aeration rate and presence of several additives containing mineral salts and hydrocarbons. Finally, the optimum condition for production of the biosurfactant was determined and the biosurfactant identity was investigated using chemical and spectroscopy methods. The maximum biosurfactant production by Pseudomonas aeruginosa PTCC 1561, was exhibited when it was grown in Brain Hearth Broth medium containing Fecl3, ZnSO4, FeSO4, starch and olive oil incubated in a 200 rpm shaker incubator at 37°C for 24 h . The structure of produced biosurfactant sugar-lipid was confirmed by chemical and spectroscopy methods

Antitumor and antibacterial activity of four fractions from Heracleum persicum Desf. and Cinnamomum zeylanicum Blume

At the present study tumor inhibition and antibacterial activity of the essential oils of Heracleum persicum and Cinnamomum zeylanicum was investigated. Methanol and petroleum ether were extracted from C. zeylanicum by potato disk method. These fractions showed cytotoxic effects in brine shrimp lethality assay (BSL). The authors found both H. persicum (57.16%) and C. zeylanicum (72.90%) had inhibition effects on Agrobacterium tumefaciens which induced crown gall tumor on potato disk. These oils also exhibited antitumor activity where IC50 was applied and the values were 2.24 and 1.20 mg/mL, respectively, for H. persicum and C. zeylanicum. C. zeylanicum also inhibited the growth of all tested Gram- positive and Gram-negative strains. In all, the findings of the present study completely correspond to the results obtained in brine shrimp lethality

Folding Thermodynamics of the Hybrid-1 Type Intramolecular Human Telomeric GQuadruplex

Guanine-rich DNA sequences that may form G-quadruplexes are located in strategic DNA loci with the ability to regulate biological events. G-quadruplexes have been under intensive scrutiny owing to their potential to serve as novel drug targets in emerging anticancer strategies. Thermodynamic characterization of G-quadruplexes is an important and necessary step in developing predictive algorithms for evaluating the conformational preferences of G-rich sequences in the presence or the absence of their complementary C-rich strands. We use a combination of spectroscopic, calorimetric, and volumetric techniques to characterize the folding/unfolding transitions of the 26-meric human telomeric sequence d[A3G3(T2AG3)3A2]. In the presence of K1 ions, the latter adopts the hybrid-1 G-quadruplex conformation, a tightly packed structure with an unusually small number of solvent-exposed atomic groups. The K1-induced folding of the G-quadruplex at room temperature is a slow process that involves significant accumulation of an intermediate at the early stages of the transition. The G-quadruplex state of the oligomeric sequence is characterized by a larger volume and compressibility and a smaller expansibility than the coil state. These results are in qualitative agreement with each other all suggesting significant dehydration to accompany the G-quadruplex formation. Based on our volume data, 432619 water molecules become released to the bulk upon the G-quadruplex formation. This large number is consistent with a picture in which DNA dehydration is not limited to water molecules in direct contact with the regions that become buried but involves a general decrease in solute–solvent interactions all over the surface of the folded structure. VC 2013 Wiley Periodicals, Inc. Biopolymers 101: 216–227, 2014. Keywords: G-quadruplexes; conformational transitions; volume; compressibility; expansibilit