Salt tolerance and glycerol accumulation of a respiration-deficient mutant isolated from the petite-negative, salt-tolerant yeast Zygosaccharomyces rouxii

A respiration-deficient (RD) mutant was isolated from the petite-negative, salt-tolerant yeast Zygosaccharomyces rouxii. One strain among sixteen glycerol-non-utilizing mutants exhibited vigorous liberation of CO2 but no uptake of O2. Furthermore, this strain lacked cytochrome aa3 and had a reduced level of cytochrome b. The few mitochondria found in cells of this strain contained few or no cristae. Salt tolerance and intracellular accumulation of glycerol by the RD strain were almost equal to that of the wild-type strain in media containing NaCl up to 2.5 M. In media with more than 3 M NaCl, the growth of the RD mutant was retarded and the intracellular accumulation of glycerol was depressed in spite of ample production.     

Effect of arteriovenous flow reversal on blood flow and metabolism in a skin flap

Twelve pig buttock island flaps (10 X 10 cm) were studied for 6 hours after arteriovenous flow reversal at the level of the pedicle. Follow-up was 48 hours. Blood pressure, Po2, pH, and lactate were measured in flap arteries and veins. Oxygen consumption was calculated. Data indicated true flow reversal. Blood pressure and Po2 in flap veins increased to systemic arterial levels. Outflow was provided by the arterial system, demonstrating venous pressure and Po2 values. Lactate increased significantly (1.8 +/- 0.5 to 4.0 +/- 2.3 mmol/liter), while pH dropped from 7.43 +/- 0.03 to 7.11 +/- 0.02. Oxygen consumption remained below baseline. In four flaps thrombosis occurred within 6 hours; no flap survived 48 hours. The results of this study do not encourage clinical application of the concept of flow reversal.     

Mutagenesis of human granulocyte colony stimulating factor

To define the structure-function relationship, we have made a number of mutants of human granulocyte colony-stimulating factor (hG-CSF) by in vitro mutagenesis. The results indicate that most of the mutations located in the internal and C-terminal regions of the molecule abolished the activity, whereas the mutants without N-terminal 4, 5, 7, or 11 amino acids retained the activity. N-terminal amino acids were also altered by cassette mutagenesis using a synthetic oligonucleotide mixture. Among them, KW2228, in which Thr-1, Leu-3, Gly-4, Pro-5 and Cys-17 were respectively substituted with Ala, Thr, Tyr, Arg and Ser, showed more potent granulopoietic activity than that of intact hG-CSF both in vitro and in vivo.     

Role of Chitinase and Chitin Oligosaccharides in Lignification Response of Cultured Carrot Cells Treated with Mycelial Walls

Chitinase activity was induced in cultured carrot cells by incubationwith mycelial walls of a fungus, Chaetomium globosum. Both intra-and extracellular chitinases were resolved into four componentsby gel filtration chromatography. The extracellular enzymesliberated soluble oligosaccharides of different sizes from insolublechitin, suggesting that these carrot chitinases are endo-hydrolases.The solubilized chitinase digests obtained from insoluble mycelialwalls of C. globosum and chitin were fractionated by gel filtrationchromatography, and the elicitor activity of each fraction forthe accumulation of phenolic acids in cultured carrot cellswas determined. In both solubilized fragments of fungal wallsand of chitin, elicitor-active oligosaccharides were distributedin many fractions, however, potent activity for inducing phenolicacid synthesis was observed in the high molecular weight fractions. (Received October 5, 1987; Accepted February 12, 1988)     

The usefulness of CHAPS as a non-cytotoxic stabilizing agent in purification of growth factors

Among several detergents, a zwitterionic detergent, 3-[(3-cholamidopropyl)dimethylammonio]-1-propane sulfonate (CHAPS), was found to be least cytotoxic for cultured mammalian cells. CHAPS improved the activity recovery and elution profile of crude and purified fibroblast growth factors (FGFs) during chromatographies. Diluted preparations of FGFs were stabilized by CHAPS against the loss during storage. Amino acid sequence analysis was not disturbed by CHAPS. CHAPS was removable by reversed-phase high-performance liquid chromatography. These results indicate that CHAPS is useful as a non-cytotoxic stabilizing agent in purification of various kinds of bioactive polypeptides.Abbreviations -MEM Alpha Modification of Eagle's Minimal essential medium - CHAPS 3-[(3-cholamidopropyl)dimethylammonio]-1-propane sulfonate - CHAPSO 3-[(3-cholamidopropyl)dimethylammonio]-2-hydroxy-1-propane sulfonate - CS Calf Serum - EGF Epidermal Growth Factor - FGF Fibroblast Growth Factor - HPLC High-Performance Liquid Chromatography - NGF Nerve Growth Factor - NOG 1-O-n-octyl--D-glucopyranoside - NP-40 Nonidet P-40 - PBS Phosphate-Buffered Saline - SB 12 3-(dodecylmethylammonio)-1-propane sulfonate - SDS Sodium Dodecyl Sulfate - TGF- and Transforming Growth Factor type and      

Preventive effect of MCI-186 on 15-HPETE induced vascular endothelial cell injury in vitro

Using cultured bovine aortic endothelial cells, the effects of MCI-186, a radical scavenger, were studied on arachidonic acid metabolism and on the cell injury caused by 15-HPETE. MCI-186 at 3 X 10(-5) M enhanced prostacyclin production in the intact endothelial cells without affecting phospholipase A2. When endothelial cell homogenates were used as an enzyme source, it was found that MCI-186 stimulated the conversion of arachidonic acid to prostacyclin like phenol, perhaps by trapping OH radicals produced in the process of the conversion of PGG2 to PGH2. On the other hand, MCI-186 was found to inhibit lipoxygenase metabolism of arachidonic acid in cell free homogenates of rat basophilic leukemia cells. The lipoxygenase inhibition caused by 3 X 10(-5) M MCI-186 was almost equivalent to that caused by 3 X 10(-6) M BW 755C. MCI-186 remarkably protected against endothelial cell damage caused by 15-HPETE. 3 X 10(-5) M of 15-HPETE caused endothelial cell death in about 60% of the population: however, pretreatment of the cells with 10(-5) M of MCI-186 or concomitant addition of 10(-5) M of MCI-186 with 15-HPETE to the cultures prevented the cell death completely. These results suggest that MCI-186 may become an unique anti-ischemic drug.     

Colchicine-binding activity of carrot tubulin at different culture age

Tubulin contents in the extract from cultured carrot cells at different growth phases were investigated by measuring colchicine-binding activity. The addition of vinblastine and dithiothreitol to the reaction mixture appreciably improved the stability of both free and colchicine-bound tubulins. Colchicine-binding activity in the cell extract obtained from stationary phase was more labile than that from log phase though the extract showed higher affinity to colchicine. After purification, however, tubulin from the cells at different growth phases showed the same affinity and its colchicine-binding activity was much more stable than in crude extract. The colchicine-binding activity in the crude extract was corrected for the decay during measurement and apparent difference in the affinity so that the activity in the cells containing different kind and amount of interefering substances could be compared. The corrected amount of colchicine that binds to the 100,000×g extract was 46 pmol/10⁵ cells at log phase. It decreased with the progression of culture age from linear to stationary phase. Combining the data with the morphological observation, it was suggested that the log phase cells contained larger free tubulin pool than the linear or stationary phase cells.     

In vitro toxicity testing for antibacterials against human keratinocytes

The use of cultured human keratinocytes in an in vitro comparison of topical antibacterial toxicity for epithelial cells was examined. The complement of three assessments allows testing of epithelial migration, growth, and survival. The three assessments included (1) flow cytometry for determination of cell survival, (2) a comparison of confluent cell culture growth after antibacterial exposures, and (3) an evaluation of cell migration using a technique of dermal explants to study radial migration. A comparative ranking of the toxicities of the various topical antibacterials was determined with the three assessments. This has confirmed anecdotal reports that many of the topical antibacterials are cell-toxic and may inhibit wound healing. This information can be directly extrapolated to the clinical setting, unlike many of the animal data for wound healing that currently exist.