The Effect of Nonanal on Dipodascus aggregatus II. Influence of the Prehistory of the Inoculum and of the Presence of Ethanol

Nonanal, added in ethannlic solution, in concentrations lower than 40 to 80 μM did not affect the growth of Dipodascus aggregatus, provided the inoculum had been harvested from the exponential phase of growth. Growth could even be inhibited by 80 μM. If the inoculum had been grown to the exponential phase and then for another period, to the acceleration phase, in fresh liquid medium, growth was strongly promoted by 80 μM nonanal. If cells from the exponential phase were grown for another period in the supernatant fluid of centrifuged cultures from the exponential phase, 80 μM affected growth in the following way: in five different experiments growth was not stimulated, in one experiment undoubtedly promoted, and weakly stimulated in another one. The growth of cultures inoculated with cells grown only on malt agar was not affected by 80 μM nonanal. Pretreatment of cells, harvested from the acceleration phase, with nonanal (80 μM) in the presence of ethanol did not diminish the growth-promoting action of nonanal on the cultures inoculated with these cells. Nonanal, in the absence of ethanol, in a concentration of 10 μM did not affect the growth of cells, harvested from the acceleration phase, whereas 100 μM nonanal strongly inhibited growth. An attempt is made to explain the results starting from the endogenous metabolism.     

The Effect of Nonanal on Dipodascus aggregatus IV. Studies with Different Carbon Sources

Nonanal (80 μ) in ethanolic solution stimulated the growth of Dipodascus aggregatus with fructose (55.5 mM) as carbon source (inoculum grown with fructose or glucose). If the inoculum had been grown with galactose, neither growth with galactose nor growth with glucose was affected by nonanal. If the inoculum had been grown with glucose, growth with galactose was weakly. stimulated. —Growth with galactose (galactose-grown inoculum) was strongly stimulated by nonanal if xylose at a low concentration (0.53 mM) was added. — The oxygen uptake of glucose grown cells with glucose as substrate was stimulated by 200 μM nonanal in the absence of ethanol. The respiratory activity of galactose-grown cells was also stimulated with galactose as well as with glucose as substrate. In the absence of exogenous substrate the oxygen uptake of glucose-grown cells was weakly stimulated by nonanal whereas that of galactose-grown cells was strongly stimulated.     

The Effect of Nouaual on Dipodascus aggregatus

The growth of a strain of Dipodascus aggrrgatus Francke-Grosmann was strongly promoted by the aliphatic aldehyde nonanal. The highest effect was found with 80–160 μmol of nonanal per 1. The growth-promoting activity of nonanal is principally the result of an ability to shorten the lag phase. Neither the maximum value for growth nor the growth rate seem to be increased. The growth-promoting activity of nonanal could be observed only if the cells used for inoculation were taken from a culture in the phase of accelerated growth. The highest growth-promoting activity was observed when the nonanal was added before inoculation, a large effect was still observed when it was added 24 hours after inoculation, but there was no effect when it was added 33 hours after inoculation. The growth-promoting activity of nonanal remained unchanged when a mixture of 15 vitamins and growth factors was given to the medium. Nonanol and nonanoic acid stimulated growth, although to a lower degree than nonanal. There was a gradual increase in the growth-promoting effect of nonanal as the pH of the medium was increased between 3.0 and 8.0, showing that this effect is most pronounced at the higher pH values.     

Microthrix parvicella, a filamentous bacterium from activated sludge: growth on Tween 80 as carbon and energy source

Microthrix parvicella, cultivated in a medium with Tween 80 and Casamino acids, utilized only the oleic acid moiety of Tween 80 as carbon and energy source. The cell yield from Tween 80 was about 0.32 g dry weight of cells per g of Tween 80 consumed. As only the oleic acid moiety of Tween 80 was utilized, the cell yield from oleic acid was 1.3 g dry weight of cells per g oleic acid consumed. The amount of carbon produced as CO2 was less than 30% of the oleic acid-carbon and this low value was in agreement with the high cell yield. In batch culture M. parvicella stored large amounts of lipid material during the early growth phase. The fatty acids of the lipid globules were similar to the fatty acids supplied as carbon source. The percentage composition of the biomass changed to give C/N percentage ratios of about 15 during the early growth phase due to the high concentration of internal lipids and the low concentration of protein. The growth rate in batch culture was about 0.016 h-1 but was affected by the concentration of Casamino acids in the medium.     

The Effect of Various Aliphatic Aldehydes and Related Compounds on the Growth of Dipodascus aggregatus

The growth of Dipodascus aggregatus in cultures inoculated with cells from the acceleration phase of growth was stimulated by the saturated and unbranched aliphatic C(3) C(4) , and C(6) to C(11) aldehydes (80 μM]. Nonanal was most active in stimulating growth. The C(12) aldehyde inhibited growth. The C(5) , aldehyde generally inhibited growth. - Nonan did not affect growth. 2-Nonanone and 5-nonanone promoted growth insignificantly. - In cultures inoculated with cells from the exponential phase growth was unaffected or even inhibited by all the aldehydes tested. The C(4) , C(5) , C(10) , and C(11) aldehydes inhibited growth to a larger extent than nonanal.     

An Analysis of the Nutritional Requirements for Fatty Acids of Paramecium aurelia

SYNOPSIS. Axenically cultivated Paramecium aurelia , stock 299, required a fatty acid for growth. This need was satisfied by oleic acid and oleic acid-containing lipids. These included: TEM-4T (tartaric acid esters of tallow monoglycerides), certain phospholipids (crude as well as highly purified preparations), Tween 80, 85, Span 80 and glyceryl monoleate. High concentrations of oleic acid in the medium inhibited growth. This inhibition was partially released or annulled by certain mixtures of "non essential" fatty acids or by increasing the stigmasterol content of the growth medium. Definite but non-stoichiometric levels of oleic acid and sterol were required for optimal growth. Tween 60, a non-ionic emulsifier similar in its surfactant properties to Tween 80, stimulated growth in the presence of suboptimal amounts of oleic acid but failed itself to replace oleic acid as a growth requirement.     

Relationship between IAA-induced elongation growth and plasma membrane NADH oxidase in soybean (Glycine max Merr.) hypocotyls

A relationship between the activity of NADH oxidase of the plasma membrane and the IAA-induced elongation growth of hypocotyl segments in etiolated soybean (Glycine max Merr.) seedlings was investigated. The plasma membrane NADH oxidase activity increased in parallel to IAA effect on elongation growth in hypocotyl segments. Actually, NADH oxidase activity was stimulated 3-fold by 1 u,M IAA, and the elongation rate of segments was stimulated 10-fold by 10 iM IAA. The short-term elongation growth kinetics, however, showed that the IAA-induced elongation of hypocotyl segments was completely inhibited by plasma membrane redox inhibitors such as actinomycin D and adriamycin, at 80 μM and 50 μM respectively. In addition, 1 mM actinomycin D inhibited the IAA-stimulated NADH oxidase activity by about 80%. However, adriamycin had no effect on NADH oxidase activity of plasma membrane vesicles. Based on these results, the plasma membrane redox reactions seemed to be involved in IAA-induced elongation growth of hypocotyls, and the redox component responding to IAA was suggested to be NADH oxidase.     

Inhibitory effect of ethanol on growth and solute accumulation by Saccharomyces cerevisiae as affected by plasma-membrane lipid composition

Incorporation of ethanol (1.0 or 1.25 M) into exponential-phase cultures of Saccharomyces cerevisiae NCYC 366 growing anaerobically in a medium supplemented with ergosterol and an unsaturated fatty acid caused a retardation in growth rate, which was greater when the medium contained oleic rather than linoleic acid. Ethanol incorporation led to an immediate drop in growth rate, and ethanol-containing cultures grew at the slower rate for at least 10 h. Incorporation of ethanol (0.5 M) into buffered (pH 4.5) cell suspensions containing d-[6-³H] glucose, d-[1-¹⁴C] glucosamine, l-[U-¹⁴C] lysine or arginine, or KH₂ ³²PO₄ lowered the rate of solute accumulation by cells. Rates of accumulation of glucose, lysine and arginine were retarded to a greater extent when cells had been grown in the presence of oleic rather than linoleic acid. This difference was not observed with accumulation of phosphate. Ethanol was extracted from exponential-phase cells by four different methods. Cells grown in the presence of linoleic acid contained a slightly, but consistently, lower concentration of ethanol than cells grown in oleic acid-containing medium. The ethanol concentration in cells was 5–7 times greater than that in the cell-free medium.     

Selective changes in fatty acid composition of phosphatidylserine in rat erythrocyte membrane induced by nitrate

The relationship between nitrate which is formed from inhaled nitrogen dioxide, a common air pollutant, and changes in fatty acid metabolism of phosphatidylserine in rat erythrocytes has been examined. When erythrocytes were incubated at 37°C for 60 min with fatty acid, the incorporation rate of [1-¹⁴C]arachidonic acid and [9,10-³H]palmitic acid into phosphatidylserine was 15% (80 pmol/h per μmol lipid phosphorus) and 20% (12 pmol/h per μmol lipid phosphorus) of those into phosphatidylethanolamine, respectively. By the addition of 1.0 mM sodium nitrate or 0.5 μM ionophore A23187 to the incubation mixture, the rate of incorporation of both arachidonic acid and palmitic acid into phosphatidylethanolamine was stimulated 1.45-fold. On the other hand, the incorporation of palmitic acid into phosphatidylserine was little affected, while that of arachidonic acid was stimulated 1.35-fold. An increase in arachidonic acid of phosphatidylserine was also found by the addition of nitrate or ionophore A23187. This increase was dependent on the concentration of extracellular calcium and observed by the addition of other chaotropic anions in the order SCN >CIO₄^? > NO₃^?. It seems likely, therefore, that nitrate causes changes in erythrocyte membranes to facilitate calcium uptake. Increasing the concentration of intracellular calcium may cause stimulation of acyl-CoA:lysophospholipid acyltransferase and/or endogenous phospholipase A₂.     

Somatic embryogenesis in liquid cultures of a tetraploidAlstroemeria

A simple and efficient procedure was developed for regeneration of a tetraploid cultivar ofAlstroemeria (A. pelegrina x A. psittacina) via somatic embryogenesis in liquid cultures. Embryogenic callus induced from mature zygotic embryos, cultured on MS medium supplemented with 40 μM NAA and 20 μM kinetin, was used as inoculum for liquid cultures. Pre-culture of the callus on MS medium supplemented with 80 μM NAA for two days was essential for cell proliferation in the liquid medium. Embryogenic cell aggregates, obtained by sieving through a 750 μm nylon mesh, continued to proliferate in media containing 10 or 20 μM NAA and 10 or 20 μM kinetin. When transferred to a semi-solid half strength MS medium supplemented with casein hydrolysate, cell aggregates successfully differentiated into plantlets which later grew to maturity under greenhouse conditions.     

Ethanol Inhibition Kinetics of Kluyveromyces marxianus Grown on Jerusalem Artichoke Juice

The kinetics of ethanol inhibition on cell growth and ethanol production by Kluyveromyces marxianus UCD (FST) 55-82 were studied during batch growth. The liquid medium contained 10% (wt/vol) inulin-type sugars derived from an extract of Jerusalem artichoke (Helianthus tuberosus) tubers, supplemented with small amounts of Tween 80, oleic acid, and corn steep liquor. Initial ethanol concentrations ranging from 0 to 80 g/liter in the liquid medium were used to study the inhibitory effect of ethanol on the following parameters: maximum specific growth rate (μ_max), cell and ethanol yields, and sugar utilization. It was found that as the initial ethanol concentration increased from 0 to 80 g/liter, and maximum specific growth rate of K. marxianus cells decreased from 0.42 to 0.09 h⁻¹, whereas the ethanol and cell yields and sugar utilization remained almost constant. A simple kinetic model was used to correlate the μ_max results and the rates of cell and ethanol production, and the appropriate constants were evaluated.     

Influence of Iodine and Bromine on Growth of Some Red Algae in Axenic Culture

Some red algae in axenic culture have been cultivated with different additions of iodine and bromine. Polysiphonia urceolata appeared to have an absolute demand for iodine. Additions could be made either as organically bound iodine or as inorganic iodine. A linear correlation between amount of added iodide and growth was found for iodide concentrations from 1 μmol up to at least 8 μmμmumol per 1. Nemalion proved to be indifferent to iodide additions, while Goniotrichum elegans was inhibited by concentrations higher than 0.4 μumol per 1, which corresponds to that of natural seawater. High additions of iodine generally inhibited growth of nonaxenic algae. Acrochaetium made an exception, being stimulated by 4 μumol per I. Bromine in the same concentration as that of seawater, viz. 814.3 μmol pa 1 inhibited growth of most species, but amounts smaller than 50 μumol had in some experiments a slightly increasing effect. Bromine seems, however, not to play an essential part in the metabolism of Polysiphonia urceolata.     

Chemical and Physical Factors Influencing Growth of Phytophthora parasitica var. nicotianae on Vegetable Oils

Factors influencing the growth of Phytophthora parasition var. nicotiona on vegetable oil liquid media were studied. This fungus grew poorly on oleic acid, triolein, and tristearin. Cholesterol and α-tocopherol reversed the toxicity of oleic acid. Growth was often stimulated by addition of mineral oil to a glucose medium, and sterols dissolved in mineral oil frequently stimulated grwoth. Shaking produced a 5-fold or more increase in growth on either glucose or cottonseed oil media. Cholesterol (20 μ/ml further increased growth on glucose meidum in shake culture by at least 100%. Growth was usually better at pH 6.7 than at 5.4 or 7.7. Growth in shake culture on a glucose medium supplemented with cholesterol and α-tocopherol approached that occuring on vegetable oil media.     

Insulin-like growth factor-I stimulates amino acid transport in a glutamine-deprived human neuroblastoma cell line

It is still unknown how insulin-like growth factor-I (IGF-I) regulates cancer cell growth in the condition of the limited availability of key nutrients, such as glutamine. We investigated the effects of IGF-I on cell growth and amino acid transport in a glutamine-deprived human neuroblastoma cell line, SK-N-SH. Cell growth was measured, and ³H-labeled amino acid transport was assayed after treatment with or without IGF-I (50 ng/ml) in 2 mM (control) and 100 μM glutamine concentrations. Cell growth rates were dependent on glutamine concentrations. IGF-I stimulated cell growth in both 2 mM and 100 μM glutamine. IGF-I stimulated glutamine transport in 100 μM glutamine with the mechanism of increasing carrier V_max, but had no effect in 2 mM glutamine. IGF-I also stimulated leucine, glutamate and 2-(methylamino)isobutyric acid transport in 100 μM glutamine. There were significant increases in [³H]thymidine and [³H]leucine incorporation in IGF-I-treated cells in both 2 mM and 100 μM glutamine. These data suggest that IGF-I stimulates cell growth by increasing amino acid transport in the condition of low glutamine levels in a human neuroblastoma cell line. This mechanism may allow to maintain cell growth even in nutrient-deprived tumor tissues.     

Effects of oleic acid on ionic channels of plasma membranes of green alga Chara corallina

Extracellular application of 5–30 μM oleic acid (C_18:1:9cis) produced a significant decrease in the amplitude of Ca²⁺ currents and Ca²⁺-activated chloride currents in plasma membrane of green alga Chara corallina. Introduction of 10 μM oleic acid intracellularly suppressed the development of the Ca²⁺ current. This inhibition of the Ca²⁺ current was reversible, and the Ca²⁺ conductivity of the cell membrane was restored after the removal of oleic acid. There were no changes in the non-specific leakage current, which indicates the intactness of the lipid component of the membrane. An increase of the oleic acid concentration up to 50–100 μM in the extracellular solution induced almost complete and irreversible suppression of inward currents and caused a substantial increase in the non-specific leakage current and conductivity of plasma membrane, suggesting its disruption. We suggest that the mechanism of cytotoxicity of oleic acid may be related to transport across plasma membrane of oleic acid and its complexes with α-lactalbumin (HAMLET and La-OA).     

Influence of some oils and surfactants on ligniolytic activity,growth and lipid fatty acids of Phanerochaete chrysosporium

Summary Ligninase production by Phanerochaete chrysosporium MZKIBK-B 186 was increased when the culture medium was supplemented with an emulsion of oleic acid. Addition of linseed oil enhanced fungal biomass synthesis. Under the growth conditions used in our tests, the fungus was capable of accumulating fatty acids from the culture medium into cell lipids. Addition of oleic acid, Tween 80, or 3-[(cholamidopropyl)-dimethylammonio]-1-propanesulphonate (CHAPS), which are known to increase ligninase production by fungi, resulted in oleic acid enrichment of whole cell and polar lipids. Offprint requests to: D. Le相似文献   

Control of membrane polar lipid composition in Acholeplasma laidlawii a by the extent of saturated fatty acid synthesis

The low level of endogenous fatty acid synthesis in Acholeplasma laidlawii A strain EF22 was found to be caused by a deficiency of pantetheine in the lipid-depleted growth medium. By supplementing the oleic acid-containing medium with increasing concentrations of pantetheine, saturated fatty acid synthesis was stimulated (having an apparent $\text{K}{}_{\mathrm{<mtext>m</mtext>}}$ of 5 μM for pantetheine) and the incorporation of endogenously synthesized fatty acids in membrane lipids increased markedly. Furthermore, carotenoid biosynthesis was stimulated. Exogenous palmitic acid was found to inhibit partially the endogenous fatty acid synthesis. A gradual stimulation of fatty acid synthesis was accompanied by a linear increase in the molar proportion between the two dominating membrane glucolipids, monoglucosyldiacylglycerol and diglucosyldiacylglycerol. The total amount of charged membrane lipids decreased upon increasing the degree of fatty acid saturation. These regulations are discussed in terms of membrane stability, and influence of membrane molecular ordering and surface charge density on lipid polar head group synthesis.     

The effects of pravastatin,an HMG-CoA reductase inhibitor,on cell viability and dna production of rat hepatocytes

Some metabolites and products of mevalonic acid are involved in various cellular functions, particularly cell growth. In this study, we assessed the effects of pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, on cell viability and DNA production of rat hepatocytes stimulated with epidermal growth factor. Pravastatin (0.1 to 10μM) induced a dose-dependent reduction of DNA synthesis, assessed by ³H-thymidine incorporation in rat hepatocytes, which dropped by approximately 60% al a drug concentration of 10 μM. This suppression of DNA synthesis was nearly reversed by exogenous mevalonic acid, but was not prevented by purified low-density lipoprotein cholesterol. Pravastatin did not affect the mitochondrial reduction of Dimethylthiazolyl-diphenyl-tetrazolium bromide (MTT), but induced apoptotic change as assessed by nuclear chromatin staining. This apoptolic change was also reversed by exogenous mevalonic acid. These results indicate that mevalonic acid metabolites are necessary for DNA synthesis by rat hepatocytes stimulated by epidermal growth factor and for suppressing cell death.     

l-Glutamic Acid Fermentation

A study was made on the differences between Brevibacterium thiogenitalis No. 653 and its oleic acid-requiring mutant D-248 in some physiological characteristics.

The most important difference of the characteristics was found in their intracellular fatty acid contents. Namely, the cellular oleic acid content of D-248 was scarcely affected by biotin but limited by the oleic acid which was added to the medium.

On the other hand, various enzyme activities and rates of oxygen uptake for several organic acids were found to be slightly different between the two strains.

These observations suggest that oleic acid has an important role for the production of l-glutamic acid.

The effect of biotin and oleic acid on the cellular fatty acid contents, and the relation between the cellular fatty acid contents and the productivity of l-glutamic acid were investigated using Brevibacterium thiogenitalis No. 653 and its oleic acid-requiring mutant, D-248.

While the synthesis of palmitic acid in D-248 was stimulated by biotin and competitively reversed by oleic acid added to the culture medium, the level of cellular oleic acid was scarcely affected by biotin but regulated by oleic acid in the medium.

For the productivity of L-glutamic acid, the most important factor was the level of cellular oleic acid, and the effect of cellular palmitic acid was considerably weak. This relation was subjected to a figuration and able to be expressed on the whole as one exponential-like curve. An amount of over 70 per cent of cellular fatty acids was distributed in the phospholipid fraction and its fatty acid composition was almost the same as that of whole cells.