Characterization and feasibility of a miniaturized stirred tank bioreactor to perform E. coli high cell density fed-batch fermentations.

The use of small scale bioreactors that are mechanically and functionally similar to large scale reactors is highly desirable to accelerate bioprocess development because they enable well-defined scale translations. In this study, a 25-mL miniaturized stirred tank bioreactor (MSBR) has been characterized in terms of its power input, hydrodynamics, and volumetric oxygen transfer coefficient (k(L)a) to assess its potential to grow high cell density (HCD) cultures using adequate scale-down criteria. Engineering characterization results show scale down, based on matched specific power input (P(G)/V), is feasible from a 20-L pilot scale stirred tank bioreactor.

Copper-catalyzed dimerization fragmentation cyclization reactions of (E)-1-en-4-yn-3-ols as a versatile approach for the synthesis of multisubstituted 1H-cyclopenta[b]naphthalenes.

An intermolecular condensation reaction of 1,3,5-triarylenynols catalyzed by copper is developed. This reaction is a straightforward method for the synthesis of highly conjugated 1H-cyclopenta[b]naphthalene. Fluorescent properties have been determined for some of the products.

Growth and productivity impacts of periplasmic nuclease expression in an Escherichia coli Fab' fragment production strain.

Host cell engineering is becoming a realistic option in whole bioprocess strategies to maximize product manufacturability. High molecular weight (MW) genomic DNA currently hinders bioprocessing of Escherichia coli by causing viscosity in homogenate feedstocks. We previously showed that co-expressing Staphylococcal nuclease and human Fab' fragment in the periplasm of E.

Sc(OTf)3-catalyzed synthesis of indoles and SnCl4-mediated regioselective hydrochlorination of 5-(arylamino)pent-3-yn-2-ones.

Highly substituted indole derivatives bearing alkyl and aryl moieties can be prepared by Sc(OTf)(3)-catalyzed Friedel-Crafts alkenylation of 5-(arylamino)pent-3-yn-2-ones. In addition, a method for regioselective hydrochlorination of 5-(arylamino)pent-3-yn-2-ones mediated by SnCl(4) in moderate to good yields (up to 84%) has been developed. The resulting exclusive Z-selectivity of the C-Cl bond can be further exploited using cross C-N coupling reactions.

Performance evaluation of a double drum dryer for potato flake production.

A double drum dryer working under atmospheric pressure was developed for water evaporation rate of 20 kg/h. Potato slurry of 12% solid concentration was dried to obtain potato flakes. Experiments were carried out at drum speed of 5 to 30 rpm, steam pressure 2 to7 kg/cm(2) gauge (saturation temperature 120-164 °C) and liquid level 5 to 10 cm at the nip of drums.

Large-scale assessment of the zebrafish embryo as a possible predictive model in toxicity testing.

Background: In the drug discovery pipeline, safety pharmacology is a major issue. The zebrafish has been proposed as a model that can bridge the gap in this field between cell assays (which are cost-effective, but low in data content) and rodent assays (which are high in data content, but less cost-efficient). However, zebrafish assays are only likely to be useful if they can be shown to have high predictive power.

Over expression of rice chitinase gene in transgenic peanut (Arachis hypogaea L.) improves resistance against leaf spot.

A Rice chitinase-3 under enhance version of CaMV 35S was introduced into peanut (Arachis hypogaea L.) through Agrobacterium mediation. Agrobacterium tumefaciens strain LB4404 was used harboring the binary vector (pB1333-EN4-RCG3) containing the chitinase (chit) and hygromycin resistance (hpt) gene as selectable marker.

Zebrafish embryos and larvae: a new generation of disease models and drug screens.

Technological innovation has helped the zebrafish embryo gain ground as a disease model and an assay system for drug screening. Here, we review the use of zebrafish embryos and early larvae in applied biomedical research, using selected cases. We look at the use of zebrafish embryos as disease models, taking fetal alcohol syndrome and tuberculosis as examples.

FeCl3-mediated synthesis of polysubstituted tetrahydroquinolines via domino Mannich/Friedel-Crafts reactions of aldehydes and amines.

A useful method to construct highly substituted tetrahydroquinolines has been developed through an iron(III) chloride-mediated domino Mannich and intramolecular Friedel-Crafts alkylation followed by intermolecular Friedel-Crafts alkylation reactions of aliphatic aldehydes with aromatic amines.

Large-scale analysis of acute ethanol exposure in zebrafish development: a critical time window and resilience.

Background: In humans, ethanol exposure during pregnancy causes a spectrum of developmental defects (fetal alcohol syndrome or FAS). Individuals vary in phenotypic expression. Zebrafish embryos develop FAS-like features after ethanol exposure.

Electrophile-driven regioselective synthesis of functionalized quinolines.

Highly substituted 3-iodoquinolines bearing different alkyl and aryl moieties can be synthesized in moderate to excellent yields (up to 99%) by 6-endo-dig iodocyclization of 2-tosylaminophenylprop-1-yn-3-ols with molecular iodine (I(2)) under mild conditions. The cyclization is highly regioselective and the resulting 3-iodoquinolines can be further functionalized by various coupling reactions.

Zebrafish embryo development in a microfluidic flow-through system.

The zebrafish embryo is a small, cheap, whole-animal model which may replace rodents in some areas of research. Unfortunately, zebrafish embryos are commonly cultured in microtitre plates using cell-culture protocols with static buffer replacement. Such protocols are highly invasive, consume large quantities of reagents and do not readily permit high-quality imaging.

Electrophilic carbocyclization of aryl propargylic alcohols: a facile synthesis of diiodinated carbocycles and heterocycles.

Diiodinated carbocycles and oxygen heterocycles can be readily synthesized by electrophilic carbocyclization of aryl propargylic alcohols in moderate to good yields under mild conditions. The resulting diiodide can be further exploited by subsequent oxidizing and coupling reactions. Both the iodine anion and cation generated from I(2) are used effectively.

Brønsted acid catalyzed cyclization of hydroxylated enynes: a concise synthesis of five-membered heterocycles.

A mild and direct pathway for the formation of five-membered heterocyclic compounds from hydroxylated enynes has been developed. In this reaction, hydroxylated enynes were selectively transformed into five-membered heterocyclic compounds 2, with an allene moiety at the 3-position, in the presence of F(3) CSO(3) H (0.1 mol %).

Iodine-induced regioselective C-C and C-N bonds formation of N-protected indoles.

A mild, metal-free, and environmently benign iodine-promoted regioselective C-C and C-N bonds formation of N-protected indole derivatives giving 2,3'-biindoles 2 and 4-(1H-indol-2-yl)morpholines 4 is successfully demonstrated. Various bioactive 2,3'-biindoles and 4-(1H-indol-2-yl)morpholines, bearing electron-rich to moderately electron-poor substituents, can be prepared in moderate to good yields.

Platinum/scandium-cocatalyzed cascade cyclization and ring-opening reaction of tertiary amines with substituted salicylaldehydes to synthesize 3-(aminoalkyl)coumarins.

The synthesis of 3-(aminoalkyl)coumarins starting with a platinum/scandium-cocatalyzed oxidative dehydrogenation of α,β-C(sp(3))-H bonds of tertiary amines in the presence of ambient oxygen followed by reactions with substituted salicylaldehydes is revealed. The in situ formed enamines reacted with various salicylaldehydes, which resulted in the development of a one-pot synthetic protocol involving aldol reaction, cyclization, and then ring-opening.

Synthesis of five- and six-membered dihalogenated heterocyclic compounds by electrophile-triggered cyclization.

Highly substituted dihalogenated dihydrofurans, dihydropyrroles, and dihydro-2H-pyrans bearing alkyl, vinyl, aryl, and heteroaryl moieties can be prepared in good to excellent yields (up to 99%) by allowing 1,4-butyne-diol, 4-aminobut-2-yn-1-ol, and pent-2-yne-1,5-diol derivatives to react with different electrophiles (I(2), IBr, and ICl) at room temperature. Both halogen atoms generated from electrophiles were used effectively. The resulting halides can be further exploited by using palladium-catalyzed coupling reactions.

The role of diamondback moth cuticle surface compounds in pre-penetration growth of the entomopathogen Isaria fumosoroseus.

Transcript patterns elicited in response to hosts can reveal how fungi recognize suitable hosts and the mechanisms involved in pathogenicity. These patterns could be fashioned by recognition of host-specific topographical features or by chemical components displayed or released by the host. We investigated this in three isolates of Isaria fumosoroseus which has shown considerable pathogenic ability against Plutella xylostella.

Platinum-catalyzed Michael addition and cyclization of tertiary amines with nitroolefins by dehydrogenation of alpha,beta-sp3 C-H bonds.

A mild platinum-catalyzed oxidative dehydrogenation of alpha,beta-C(sp(3))-H bonds of tertiary amines in the presence of ambient oxygen is revealed, and the in situ formed enamines subsequently reacting with various nitroolefins resulted in the development of two one-pot synthetic protocols involving Michael addition-elimination and Michael addition-cyclization. By using different functionalized nitroolefins compatible with the current oxidative conditions, two types of structurally divergent products, trisubstituted enamines and chromano[2,3-b]piperidines, could be expediently accessed, respectively.

Identification and Characterization of Novel Isolates of Pyrenophora tritici-repentis from Arkansas.

Tan spot, caused by Pyrenophora tritici-repentis, is an important foliar disease of wheat (Triticum aestivum) worldwide. In a preliminary study, P. tritici-repentis isolates from Arkansas were shown to vary in virulence relative to isolates from other regions of the United States.

Unexpected domino reaction via Pd-catalyzed Sonogashira coupling of benzimidoyl chlorides with 1,6-enynes and cyclization to synthesize quinoline derivatives.

A domino reaction via palladium-catalyzed Sonogashira coupling of benzimidoyl chlorides with 1,6-enynes and then cyclization to form quinoline derivatives has been developed. The reaction conditions and the scope of the process are examined, and a plausible mechanism is proposed. The procedure is simple, rapid, and general, and the substrates are readily available.