Isolation from cultured cells

Using this system, (Z)-hinokiresinol isolated from cultured cells of A. officinalis was determined to be the optically pure (75 )-isomer, while ( )-hinokiresinol isolated from cultured cells of C. japonica had 83.3% e.e. in favor of the (7S)-enantiomer (Table 12.1). The enzymatically formed (Z)-hinokiresinol obtained following incubation of p-coumaryl p-coumarate with a mixture of equal amounts of recZHRSa and recZHRSf) was found to be the optically pure (75)-isomer, which is identical to that isolated from A. officinalis cells (Table 12.1). A similar result was obtained with the crude plant protein from A. officinalis cultured cells, where the formed (Z)-hinokiresinol was almost optically pure, 97.2% e.e. in favor of the (75)-isomer (Table 12.1). In sharp contrast, when each subunit protein, recZHRSa or recZHRSP, was individually incubated with p-coumaryl p-coumarate, ( )-hinokiresinol was formed (Table 12.1). The enantiomeric compositions of ( )-hinokiresinol thus formed were 20.6% e.e. (with recZHRSa) and 9.0% e.e. (with recZHRSP) in favor of the (7S)-enantiomer (Table 12.1). Taken together, these results clearly indicate that the subunit composition of ZHRS controls not only cis/trans selectivity but also enantioselectivity in hinokiresinol formation (Fig. 12.3). This provides a novel example of enantiomeric control in the biosynthesis of natural products. Although the mechanism for the cis/trans selective and enantioselective reaction remains to be elucidated, for example by x-ray crystallography, the enantioselective mechanism totally differs from the enantioselectivity in biosynthesis of lignans, another class of phenylpropanoid compounds closely related to norlignans in terms of structure and biosynthesis. 

Although in total four sites of phosphorylation have been defined, phosphopep-tide mapping of the EGF receptor isolated from cultured cells suggests that several other sites are modified, including serine residues. The enzymes responsible for this and the effect on the receptor are not known. 

Aoyagi, H., DiCosmo, F., and Tanaka, H., Efficient paclitaxel production using protoplasts isolated from cultured cells of Taxus cuspidata, Planta Medica, 68,420,2002. 

The cyclic polyether neurotoxins, brevetoxins (BTXs) 40 and 41, isolated from cultured cells of the red tide organism Gymnodinium breve, are depolarizing substances that open the-voltage gated sodium (Na" ") ion channels in cell walls [26]. 

Isol. from cultured cells of Aspidosperma quebracho-bianco (Apocynaceae). Amorph. powder. 

This review is focused on peptide-like compounds, however, some alkaloids have been reported from cyanobacteria. The most recent example is nostocarboline (19), which was isolated from cultured cells of the freshwater cyanobacterium Nostoc sp. [51]. This compound is a new quaternary /3-carboline alkaloid. The structure was confirmed by its total synthesis. Strikingly, the alkaloid inhibited butyrylcholinesterase (IC50 13.2 p,M). The activity is comparable to an approved drug for the treatment of Alzheimer s disease. Cyanobacteria are thus possible sources of pharmaceuticals for neurological disorders. 

Constit. of Rhamnogalacturonan II, R-10, a primary cell wall pectic polysaccharide isol. from cultured cells of Acer pseudo-platanus (Sycamore). First branched chain acidic sugar to be found as a natural product. 

Pentostatin (deoxycoformycin Fig. 4) is a purine isolated from cultures of Streptomyces antibioticus. Its mode of action involves inhibition of adenosine deaminase, which plays a key role in purine salvage pathways and DNA synthesis. As a consequence, deoxyadenosine triphosphate (dATP) is accumulated, which is highly toxic to lymphocytes. This is associated with augmented susceptibility to apoptosis, particularly in T cells. 

The identification of bacteria has traditionally required the establishment of a pure culture before any other steps are taken. Pure cultures of bacteria may sometimes be obtained from blood and spinal fluid, which are normally sterile, or from extreme environments like hot springs. However, because there are few such situations in nature, individual bacteria must generally be isolated from other cells and grown for one to five days to obtain pure cultures before identification. Some pathogenic bacteria are obligate intracellular parasites that are difficult or impossible to grow outside their mammalian host cells 37 for these, pure cultures are not feasible. 

Steinmuller, C. et al., Polysaccharides isolated from plant cell cultures of Echinacea purpurea enhance the resistance of immunosuppressed mice against systemic infections with Candida albicans and Listeria monocytogenes, Int J Immunopharmacol, 15, 605, 1993. 

Harris R.J. (1995), Processing of C-terminal lysine and arginine residues of proteins isolated from mammalian cell culture, J. Chromatogr. A 705(1) 129-134. 

In the isolated perfused kidney model, the artery of the kidney is perfused and urinary samples as well as venous blood samples can be collected to determine the drug concentration. A serious drawback of the model is that isolation and artificial perfusion greatly affect the function of the organ as shown by a dramatic drop in the glomerular filtration rate. Another in-vitro model is the isolated tubule in which samples can be taken from both the luminal and basolateral sites of the tubule [140,141]. The disadvantage of this technique as well as of the isolated kidney model, is that they require specific equipment and expertise and therefore can only be performed in rather specialized laboratories. Experiments using freshly isolated or cultured cells are more simple to carry out [142,143]. Tubular cells can be grown in a po-... 

A novel cyclic lipopeptide antibiotic was isolated from cultures of Strep-tomyces roseosporus grown in the presence of decanioc acid. Daptomycin interacts with the bacterial cell membrane and interferes with membrane potential.Unlike polymyxin B, daptomycin can target majority of clinically relevant Gram-positive pathogens. 

Alteplase Alteplase is a drag that activates human tissue plasminogen (t-PA). It is a glycoprotein of molecular mass 68,000 that is synthesized by vascular endothelial cells. t-PA cells were first isolated from cultured human melanoma cells [56-58], but currently a genetically recombined form of rt-PA is genetically engineered. 

In contrast to these findings, a glucuronoarabinoxylan isolated from oat coleoptiles did not bind to cellulose in vitro under reaction conditions that allowed other heteroxylans to bind.53 This oat heteroxylan had, however, a high percentage of arabinosyl side chains that would be likely to hinder binding sterically. A similar inability to bind to cellulose is exhibited by an arabinose-rich arabinoxylan isolated from cultured, barley-aleurone cell-walls.61... 

Fig. 3. A northern blot of poly(A)+ RNA probed with a psi cDNA clone showed enhanced levels of psi messenger RNA as phosphate starvation became more severe. Poly(A)+ RNA was isolated from cultures at 3, 6 and 9 days after transfer to —Pi or +Pi medium (A. Danon et al., unpublished data in preparation). Equal amounts of RNA (1 pg per treatment) were separated on a denaturing formaldehyde/agarose gel and used for a northern blot. The filter was probed using a psi cDNA clone (identified by —/+ screening using standard methods) as the probe. Enhanced levels of mRNA for this clone are seen as early as 3 days after transfer to —Pi medium although cell growth equivalent to the unstressed control continued until day 8.

Structure of diketopiperazines 165, isolated from the cell-free culture supernatant of the Antarctic psychrophilic bacterium Pseudoalteromonas haloplanktis TAC125, was characterized by and 13C NMR spectroscopy (05MI34). 

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