Regulation of vincamine biosynthesis and associated growth promoting effects through abiotic elicitation,cyclooxygenase inhibition,and precursor feeding of bioreactor grown Vinca minor hairy roots

Hydroxylase/acetyltransferase elicitors and cyclooxygenase inhibitor along with various precursors from primary shikimate and secoiridoid pools have been fortified to vincamine less hairy root clone of Vinca minor to determine the regulatory factors associated with vincamine biosynthesis. Growth kinetic studies revealed that acetyltransferase elicitor acetic anhydride and terpenoid precursor loganin significantly reduce the growth either supplemented alone or in combination (GI?=?140.6?±?18.5 to 246.7?±?24.3), while shikimate and tryptophan trigger biomass accumulation (GI?=?440.2?±?31.5 to 540.5?±?40.3). Loganin also downregulates total alkaloid biosynthesis. Maximum flux towards vincamine production (0.017?±?0.001 % dry wt.) was obtained when 20-day-old hairy roots were fortified with secologanin (10 mg/l) along with tryptophan (100 mg/l), naproxen (8.4 mg/l), hydrogen peroxide (20 μg/l), and acetic anhydride (32.4 mg/l). This was supported by RT PCR (qPCR) analysis where 2- and 3-fold increase in tryptophan decarboxylase (TDC; RQ?=?2.0?±?0.09) and strictosidine synthase (STR; RQ?=?3.3?±?0.36) activity, respectively, was recorded. The analysis of variance (ANOVA) for growth kinetics, total alkaloid content, and gene expression studies favored highly significant data (P?<?0.05–0.01). Above treated hairy roots were also up-scaled in a 5-l stirred-tank bioreactor where a 40-day cycle yielded 8-fold increase in fresh root mass.     

Metal‐induced rearrangement of benzothiazoline ring: Synthesis and characterization of some new organoantimony(V) derivatives of N,O, and S atom containing schiff base ligands

Some new triphenylantimony(V) derivatives of Schiff bases having the composition have been synthesized by the equimolar reactions of Ph₃SbBr₂ with newly synthesized benzothiazoline ligands, (where R = C₆H₅(H₂L¹), 4‐BrC₆H₄(H₂L²), 4‐ClC₆H₄(H₂L³), 4‐CH₃‐OC₆H₄(H₂L⁴), 4‐CH₃C₆H₄(H₂L⁵)). The reaction proceeds with the rearrangement of benzothiazoline ring. All the derivatives have been characterized by elemental analyses, molecular weight measurements and their plausible structures have been proposed on the basis of IR and NMR (¹H and ¹³C) spectral studies. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:70–75, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20260     

Synthesis and liquid crystalline behaviour of substituted (E)-phenyl-4-(phenyldiazenyl) benzoate derivatives and their photo switching ability

Azobenzene derivatives containing phenyl/4-halogen-phenyl 4-{(E)-[4-(pent-4-en-1-yloxy)phenyl]diazenyl}benzoate group with different electronegative substituent (H, F, Cl, Br and I) at other end was synthesised. These azo-based benzoate derivatives have been characterised by FTIR, ¹H-NMR, ¹³C-NMR, elemental analyser, POM and UV-Vis spectroscopy. Photosaturation at 358 nm obtained after 82 s of UV irradiation and the longest thermal back relaxation time of 45 h recorded by UV-Vis. The azo derivative could be possible photolock under UV light, as observed by the improved thermal back relaxation time. The resulting photolockable chain of azobenzene might prove valuable in the development of optical device application. These azobenzene moieties also exhibit liquid crystalline behaviour with respect to the halogen substitution as an electron withdrawing group shows that strong structure property relationship exists among them.     

A Novel Fusion Protein Diphtheria Toxin–Stem Cell Factor (DT-SCF)—Purification and Characterization

Fusion toxins are an emerging class of targeted therapeutics for the treatment of cancer. Diphtheria toxin-stem cell factor (DT-SCF) is one such novel fusion toxin designed to target malignancies expressing c-kit. Since, c-kit overexpression has been reported on many types of cancers, it appeared to be a reasonably good molecule to target. In the present study, we report construction, expression, purification, and characterization of DT-SCF. DT-SCF gene coding for 1–387 amino acids of diphtheria toxin, His-Ala linker, 2–141 amino acids of SCF was cloned into expression vector with C terminal His tag. The induced DT-SCF protein was exclusively expressed in insoluble fraction. Purification of DT-SCF was achieved by inclusion body isolation and metal affinity chromatography under denaturing and reducing conditions. Purified DT-SCF was renatured partially on-column by gradually reducing denaturant concentration followed by complete refolding through rapid dilution technique. Cell viability assay provided the evidence that DT-SCF is a potent cytotoxic agent selective to cells expressing c-kit. The novelty of this study lies in employing SCF as a ligand in construction of fusion toxin to target wide range of malignancies expressing c-kit. Efficacy of DT-SCF fusion toxin was demonstrated over a range of malignancies such as chronic myeloid leukemia (K562), acute lymphoblastic leukemia (MOLT4), pancreatic carcinoma (PANC-1), and cervical carcinoma (HeLa 229). This is the first study reporting specificity and efficacy of DT-SCF against tumor cells expressing c-kit. There was significant correlation (P = 0.007) between c-kit expression on cells and their sensitivity to DT-SCF fusion toxin.     

Analytik bakterientoxischer Effekte mit Hilfe genetisch konstruierter Leuchtbakterien

Zusammenfassung Leuchtbakterienteste stellen eine elegante Methode zur schnellen, reproduzierbaren Bestimmung bakterientoxischer Effekte dar. Einer allgemeinen Anwendung steht allerdings entgegen, daß die Luminescenzeigenschaften auf relativ wenige Bakterienfamilien mit zum Teil extremen Standortansprüchen beschränkt sind. Die Übertragbarkeit der Meßergebnisse auf interessierende Anwendungen ist deshalb in vielen Fällen nicht gegeben. In der vorliegenden Arbeit wird am Beispiel eines gentechnologisch konstruierten luminescenten Abwasserstammes gezeigt, daß durch Verwendung von anwendungsspezifischen Testorganismen das Anwendungsspektrum von Leuchtbakterientesten erweitert werden kann.

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Analysis of microbial toxicity using gentechnologically constructed luminescent bacteria

Summary Luminescent bacteria bioassays represent an elegant method for fast and reproducible determination of microbial toxicity. A general application of this method is however prevented by the fact that the capability for bioluminescence is restricted to a relatively small group of bacteria with extreme environmental demands. Therefore it seems questionable whether results obtained with those organisms can be used for all interesting applications. It is shown in this paper, that the field of applications for bacterial luminescent assays can be widened using gentechnologically constructed luminescent bacteria.

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Herrn Prof. Dr. H. Hartkamp zum 60. Geburtstag gewidmet     

A numerical simulation of mixed convective and arbitrarily oblique radiative stagnation point slip flow of a CNT-water MHD nanofluid

Journal of Thermal Analysis and Calorimetry - Numerical simulation of a non-linear mathematical model governing an arbitrarily oblique slip flow of a nanofluid, with suspended carbon nanotubes in...     

On the dyadic Green's functions for Beltrami fields

A simple derivation of the Green's functions for Beltrami fields is presented for use with time-harmonic electromagnetism in homogeneous biisotropic media.     

Physico-chemical studies on Gum Dhawa (Anogeissus latifoliaWall.)

Summary The p_H of an aqueous solution of Gum Dhawa (Anogeissus latifoliaWall.) is 2.68 and it is sensitive to p_H changes. The absence of the sulphate and the presence of a slight trace of phosphate, confirms the view that the acidity is due to the presence of carboxyl groups, which are formed by the hydrolysis of the gum. The hydrogen ion activity increases up to a concentration of 3% and beyond this point it attains a steady value. The sp. cond. is zero at the zero concentration and the relation between sp. cond. and up to 3% concentration is linear and afterwards it attains a steady value. It has been found by experimental observation that the gum solution has got no buffering capacity. Neutralization curves with NaOH and Ba(OH)₂ show that the combination with alkali takes place in equivalent proportion. The viscosity of the gum solution always increases with increasing p_H on the addition of HCl. The viscosity increase with NaOH is slow in the beginning, but after p_H 4.2 it rises rapidly, attains a maximum and steeply falls off near p_H 6.7. Now it decreases slowly and again a deviation is noted at 10.5. The viscosity is maximum near about the neutralization point. This is due to the stretched chain of the polymer unit. The fall in viscosity is explained by the folding chain theory in conjunction with mass action or common ion effect and due to the destruction of the proteins, by concentrated NaOH, which forms a complex with carbohydrate polymer.The authors wish to thank Dr.R. C. Mehrotra, Professor and the Head of the Chemistry Department, for providing all facilities for this work. Our thanks are also due to the Ministry of Education, Government of India, for the award of a research scholarship to one of us (V.K.S.).