Adrenaline enhances odorant contrast by modulating signal encoding in olfactory receptor cells

Olfactory perception is influenced by hormones. Here we report that adrenaline can directly affect the signal encoding of olfactory receptor cells. Application of adrenaline suppressed action potentials near threshold and increased their frequency in response to strong stimuli, resulting in a narrower dynamic range. Under voltage-clamp conditions, adrenaline enhanced sodium current and reduced T-type calcium current. Because sodium current is the major component of spike generation and T-type calcium current lowers the threshold in olfactory receptor cells, the effects of adrenaline on these currents are consistent with the results obtained under current-clamp conditions. Both effects involved a common cytoplasmic pathway, cAMP-dependent phosphorylation. We suggest that adrenaline may enhance contrast in olfactory perception by this mechanism.

Desensitization of the GABAA receptor shifts the dynamic range of retinal horizontal cells due to light and dark adaptation

The effects of the GABAergic pathway on the dynamic range of the light response of cone-driven horizontal cells (HCs) in the carp retina were investigated using conventional intracellular recordings and computer simulations. The amplitude of the HC responses to repetitive test flashes was altered by background illumination in control Ringer's solution, but was not changed following the application of picrotoxin or bicuculline, which suggests that GABAA receptors mediate the subsequent change in light response. This phenomenon was simulated by introducing the desensitization mechanism of the GABAA receptor into a cone-HC network model. These results suggest that desensitization of the GABAA receptor shifts the dynamic range of the HCs due to light and dark adaptation.

Quantitative analysis of Na+ and Ca2+ current contributions on spike initiation in the newt olfactory receptor cell

The contribution of Na+ (INa) and T-type Ca2+ (ICa,T) currents on the action potential initiation in newt olfactory receptor cells (ORC) was investigated quantitatively. Since both the Na+ channel and T-type Ca2+ channel show rapid inactivation, it was questioned how much INa and ICa,T are activated during the gradually depolarizing initial phase of the receptor potential. Because the conventional voltage clamp technique does not allow direct current measurement during voltage changes, we estimated the amplitude of INa and ICa,T in an ionic current model. The model was constructed based on voltage clamp experiments. The estimated ratio of ICa,T/INa during the action potential induced by ramp current injection was 0.59 +/- 0.03 (mean +/- SD) under control Ringer's solution. This ratio was more than twice as large as that (0.25) obtained from the previous voltage clamp experiment using step commands. This result suggests that the T-type Ca2+ channel carries a more significant amount of current to generate the action potentials than expected previously.

Differentiation of renal cell carcinomas from angiomyolipomas by ultrasonic frequency dependent attenuation

PURPOSE

We determined the usefulness of ultrasonic frequency dependent attenuation in differentiating hyperechoic renal cell carcinoma from angiomyolipoma.

MATERIALS AND METHODS

Frequency dependent attenuation values were determined in 29 renal cell carcinomas and 13 angiomyolipomas.

RESULTS

Frequency dependent attenuation values were significantly lower in renal cell carcinomas than in angiomyolipomas (0.42 versus 0.76 dB./cm./MHz.). Two of the renal cell carcinomas were as hyperechoic as the angiomyolipomas but they were clearly differentiated by the low frequency dependent attenuation. Two other renal cell carcinomas exhibited high values because of the abundance of fibrous tissue. However, they were readily diagnosed by the typical low echoic B-mode images. Frequency dependent attenuation did not differ between histological types of renal cell carcinoma. One angiomyolipoma that was poor in fat and rich in muscle components had an exceptionally low frequency dependent attenuation. Therefore, frequency dependent attenuation values can be regarded as an inversion of computerized tomography numbers.

CONCLUSIONS

Frequency dependent attenuation measurement is a promising diagnostic aid in differentiating hyperechoic renal cell carcinomas from angiomyolipomas.

Nonselective suppression of voltage-gated currents by odorants in the newt olfactory receptor cells

Effects of odorants on voltage-gated ionic channels were investigated in isolated newt olfactory receptor cells by using the whole cell version of the patch-clamp technique. Under voltage clamp, membrane depolarization to voltages between -90 mV and +40 mV from a holding potential (Vh) of -100 mV generated time- and voltage-dependent current responses; a rapidly (< 15 ms) decaying initial inward current and a late outward current. When odorants (1 mM amyl acetate, 1 mM acetophenone, and 1 mM limonene) were applied to the recorded cell, the voltage-gated currents were significantly reduced. The dose-suppression relations of amyl acetate for individual current components (Na+ current: I(Na), T-type Ca2+ current: I(Ca), T, L-type Ca2+ current: I(Ca), L, delayed rectifier K+ current: I(KV) and Ca2(+)-activated K+ current: IK(Ca)) could be fitted by the Hill equation. Half-blocking concentrations for each current were 0.11 mM (INa), 0.15 mM (ICa,T), 0.14 mM (ICa,L), 1.7 mM (IKV), and 0.17 mM (IK(Ca)), and Hill coefficient was 1.4 (INa), 1.0 (ICa,T), 1.1 (ICa,L), 1.0 (IKV), and 1.1 (IK(Ca)), suggesting that the inward current is affected more strongly than the outward current. The activation curve of INa was not changed significantly by amyl acetate, while the inactivation curve was shifted to negative voltages; half-activation voltages were -53 mV at control, -66 mV at 0.01 mM, and -84 mV at 0.1 mM. These phenomena are similar to the suppressive effects of local anesthetics (lidocaine and benzocaine) on INa in various preparations, suggesting that both types of suppression are caused by the same mechanism. The nonselective blockage of ionic channels observed here is consistent with the previous notion that the suppression of the transduction current by odorants is due to the direst blockage of transduction channels.

Comparative ultrasonographic and angiographic study of carotid arterial lesions in Takayasu's arteritis

The purpose of this study was to compare the usefulness of ultrasonography to that of angiography for studying arterial lesions in Takayasu's arteritis. Ultrasonographic and angiographic findings from 44 carotid arteries of 22 patients with Takayasu's arteritis (2 men and 20 women; mean age, 41.2 years) were compared. Angiography was used to classify the patency of the carotid arteries into three groups: nonstenotic, stenotic, and occlusive. Ultrasonography was also used to classify the same arteries into four groups: nonstenotic, mildly stenotic, moderately stenotic, and occlusive. Thickness of the wall (intima-media complex) of the carotid artery was measured with high-frequency transducers. Angiography showed 23 carotid arteries to be nonstenotic; 12, stenotic; and 9, occlusive; whereas ultrasonography showed 16 to be nonstenotic; 18, mildly stenotic; 7, moderately stenotic; and 3, occlusive. Results of the two diagnostic modalities correlated closely (P < 0.0001). Ultrasonography, aided by color flow imaging, detected six instances of a marginal but definite blood flow that angiography had failed to reveal. Arterial wall thickness correlated closely with the severity of ultrasonographic stenosis (P < 0.005). This thickness was 1.3 +/- 0.4 mm in the nonstenotic group, 1.6 +/- 0.5 mm in the mildly stenotic group, 2.2 +/- 0.8 mm in the moderately stenotic group, and 1.9 +/- 0.2 mm in the occlusive group. Even the walls of the nonstenotic arteries were significantly thicker than those of the normal carotid arteries (0.7 +/- 0.1 mm, P < 0.01). Ultrasonography appeared to be more useful than angiography in estimating stenotic severity of the carotid artery in Takayasu's arteritis. Characteristic ultrasonic findings included luminal stenosis or occlusion on two-dimensional ultrasonograms, decrease in or lack of flow shown by color Doppler flow imaging, and concentric thickening of the carotid arterial walls. Ultrasonographic mural thickness was the most sensitive indicator of early, latent inflammation.

T-type Ca2+ channel lowers the threshold of spike generation in the newt olfactory receptor cell

Mechanisms underlying action potential generation in the newt olfactory receptor cell were investigated by using the whole-cell version of the patch-clamp technique. Isolated olfactory cells had a resting membrane potential of -70 +/- 9 mV. Injection of a depolarizing current step triggered action potentials under current clamp condition. The amplitude of the action potential was reduced by lowering external Na+ concentration. After a complete removal of Na+, however, cells still showed action potentials which was abolished either by Ca2+ removal or by an application of Ca2+ channel blocker (Co2+ or Ni2+), indicating an involvement of Ca2+ current in spike generation of newt olfactory receptor cells. Under the voltage clamp condition, depolarization of the cell to -40 mV from the holding voltage of -100 mV induced a fast transient inward current, which consisted of Na+ (INa) and T-type Ca2+ (ICa.T) currents. The amplitude of ICa,T was about one fourth of that of INa. Depolarization to more positive voltages also induced L-type Ca2+ current (ICa,L). ICa,L was as small as a few pA in normal Ringer solution. The activating voltage of ICa,T was approximately 10 mV more negative than that of INa. Under current clamp, action potentials generated by a least effective depolarization was almost completely blocked by 0.1 mM Ni2+ (a specific T-type Ca2+ channel blocker) even in the presence of Na+. These results suggest that ICa,T contributes to action potential in the newt olfactory receptor cell and lowers the threshold of spike generation.

Lipid composition of commercial bakers' yeasts having different freeze-tolerance in frozen dough

The lipid composition of some commercial bakers' yeasts having different freeze-sensitivity in frozen dough was investigated to clarify the correlation between their lipid composition and freeze-tolerance. The total lipid content including neutral lipid, free fatty acid, sterol, and phospholipid ranged between 23.0 to 32.2 mg/100 mg protein of the yeasts tested. Phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, and phosphatidylserine were the main phospholipids found in all yeast strains, but no distinct difference in these components between freeze-tolerant and freeze-sensitive strains was observed. Palmitoleic (C16:1), oleic (C18:1), palmitic (16:0), and stearic (C18:0) acids were the major fatty acids present in total lipid and phospholipid, and unsaturation indices of fatty acid in these lipid components were almost equal by the strains. The molar ratios of sterol to phospholipid of freeze-sensitive strains were higher than those of freeze-tolerant strains. The difference in the sterol-phospholipid ratio that influences the fluidity of plasma membranes in yeast cells was supposed to reflect the difference in freeze-sensitivity of bakers' yeast.

Differential regulation of the mcb and emr operons of Escherichia coli: role of mcb in multidrug resistance

The mcb operon (which is responsible for microcin B17 production) and the emr operon (which encodes a multidrug resistance pump) share a common negative regulator, EmrR. Nevertheless, compounds that induce the emr operon repress the mcb operon. The pump dedicated to microcin B17 extrusion can also protect the calls against sparfloxacin and other toxic compounds.

Bacterial degradation of glycol ethers

Assimilation of ethyleneglycol (EG) ethers by polyethyleneglycol-utilizing bacteria was examined. Ethyleneglycol ether-utilizing bacteria were also isolated from soil and activated sludge samples by enrichment-culture techniques. Three strains (4-5-3, EC 1-2-1 and MC 2-2-1) were selected and characterized as Pseudomonas sp. 4-5-3, Xanthobacter autotrophicus, and an unidentified gram-negative, non-spore-forming rod respectively. Their growth characteristics were examined: Pseudomonas sp. 4-5-3 assimilated EG (diethyleneglycol, DEG) monomethyl, monoethyl and monobutyl ethers, DEG, propanol and butanol. X. autotrophicus EC 1-2-1 grew well on EG monoethyl and monobutyl ethers, EG and primary alcohols (C1-C4), and slightly on EG monomethyl ether. The strain MC 2-2-1 grew on EG monomethyl ether, EG, primary alcohols (C1-C4), and 1,2-propyleneglycol (PG). The mixed culture of Pseudomonas sp. 4-5-3 and X. autotrophicus EC 1-2-1 showed better growth and improved degradation than respective single cultures towards EG monomethyl, monoethyl or monobutyl ethers. Intact cells of Pseudomonas sp. 4-5-3 degraded various kinds of monoalkyl ethers, which cannot be assimilated by the strain. Metabolic products were characterized from reaction supernatants of intact cells of Pseudomonas sp. 4-5-3 with EG or DEG monoethyl ethers: they were analyzed by thin-layer chromatography and GC-MS and found to be ethoxyacetic acid and ethoxyglycoxyacetic acid. Also, PG monoalkyl ethers (C1-C4), dipropyleneglycol monoethyl and monomethyl ethers and tripropyleneglycol monomethyl ether were assimilated by polypropyleneglycol-utilizing Corynebacterium sp. 7.

Breakdown of plastics and polymers by microorganisms

The interest in environmental issues is still growing and there are increasing demands to develop materials which do not burden the environment significantly. Awareness of the waste problem and its impact on the environment has awakened new interest in the area of degradable polymers. Biodegradation is necessary for water-soluble or water-miscible polymers because they eventually enter streams which can neither be recycled nor incinerated. It is important to consider the microbial degradation of natural and synthetic polymers in order to understand what is necessary for biodegradation and the mechanisms involved. This requires both biochemical insight and understanding of the interactions between materials and microorganisms. It is now widely requested that polymeric materials come from renewable resources instead of petrochemical sources. The microbial production of polymeric and oligomeric materials is also described.

Phosphorus-31 nuclear magnetic resonance study of energy metabolism in intact slow- and fast-twitch muscles of rats

The time course of the catabolism of phosphorylated metabolites was studied by phosphorus-31 NMR(31P NMR) spectroscopy over a 6-h period after the isolation of rat slow- and fast-twitch muscles, the soleus and the extensor digitorum longus (EDL), respectively, obtained without any muscle damage. In both muscles, rapid depletion of creatine phosphate was followed by a decrease in ATP. These high-energy phosphates disappeared earlier in the soleus than in the EDL. In both muscles, inorganic phosphate (Pi) largely increased in a biphasic pattern, and sugar phosphates (SP) also showed considerable increase. The NMR-visible total phosphates (NTP) increased significantly in the soleus during the latter stage of observation. This increase in NTP was attributed to an increase in Pi. Although the two muscles showed the same initial (7.21) and final (approximately 5.9) intracellular pH (pHi), the pattern of pHi decline differed between these muscles. The rapid fall of pHi in the soleus in the early stage suggests that nonlactic acid acidosis plays a significant role in postmortem changes.

Effects of moderate hypercapnia on hypothermia induced by cold He-O2 in rats

1. Effects of moderate hypercapnia (10% CO2) on rectal temperature, oxygen consumption and body weight loss were examined during and after acute hypothermia induced by cold and helium-oxygen. 2. Hypothermia induction time was reduced significantly by hypercapnia. Rewarming tended to be faster in hypercapnic animals than in normocapnic animals. 3. Hypercapnia significantly reduced body weight loss when measured during hypothermia and during normothermia after rewarming. 4. Oxygen consumption during cooling was decreased by hypercapnia. 5. Exposure to 10% CO2 during cooling may spare energy substrate and favor survival in hypothermia.

Isolation and purification of a rat liver-specific antigen from hepatocyte membrane

A rat liver-specific antigen (RLSA) solubilized with the nonionic detergent non-anonyl-N-methylglucamide was purified through affinity column chromatography with a monoclonal antibody and by high-performance liquid chromatography with a hydroxylapatite column. The purified RLSA showed a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and its molecular weight was determined to be 105,000 in the presence of 2-mercaptoethanol. The antigen was reactive to the Schiff reagent and contained glucosamine, but not galactosamine, indicating that the RLSA is a glycoprotein containing an asparagine-binding type of sugar chain.

Biodegradation of polyethylene glycol by symbiotic mixed culture (obligate mutualism)

Neither Flavobacterium sp. nor Pseudomonas sp. grew on a polyethylene glycol (PEG) 6000 medium containing the culture filtrate of their mixed culture on PEG 6000. The two bacteria did not grow with a dialysis culture on a PEG 6000 medium. Flavobacterium sp. grew well on a dialysis culture containing a tetraethylene glycol medium supplemented with a small amount of PEG 6000 as an inducer, while poor growth of Pseudomonas sp. was observed. Three enzymes involved in the metabolism of PEG, PEG dehydrogenase, PEG-aldehyde dehydrogenase and PEG-carboxylate dehydrogenase (ether-cleaving) were present in the cells of Flavobacterium sp. The first two enzymes were not found in the cells of Pseudomonas sp. PEG 6000 was degraded neither by intact cells of Flavobacterium sp. nor by those of Pseudomonas sp., but it was degraded by their mixture. Glyoxylate, a metabolite liberated by the ether-cleaving enzyme, inhibited the growth of the mixed culture. The ether-cleaving enzyme was remarkably inhibited by glyoxylate. Glyoxylate was metabolized faster by Pseudomonas sp. than by Flavobacterium sp., and seemed to be a key material for the symbiosis.

[Bacteriological and clinical studies of cefoxitin with special reference to anaerobic infections in the patients of abdominal surgery (author's transl)]

Both bacteriological and clinical studies of the effectiveness of cefoxitin (CFX) in the treatment of infections associated with abdominal surgery have been carried out at Tokyo Metropolitan Toshima Hospital from September 1979 through August 1980. The results of these studies are summarized in the following: 1. The clinical isolates from the 29 surgical patients were studied and anaerobes were found in 16 patients (55% of the patients). B. fragilis was found in 11 of the 16 patients (69%) from whom anaerobes were isolated. In all of these patients, aerobes were also isolated--most frequently E. coli or K. pneumoniae. 2. The in vitro antibacterial activity of cefoxitin (CFX) against 83 clinical isolates was compared to that of cephalothin (CET), cefazolin (CEZ) and carbenicillin (CBPC). The activity of CFX against Gram-positive bacteria was generally slightly inferior to that of the other 3 antibiotics. Among the Gram-negative aerobic organisms, CEZ was the most active against E. coli and CFX and CEZ against K. pneumoniae. However, CFX, with MIC's of 0.78-12.5 micrograms/ml, showed the greatest activity against B. fragilis, followed by CBPC, CEZ and CET, in order of decreasing activity. 3. CFX was administered in a 1-hour drip infusion to 3 patients following abdominal surgery, and concentrations of CFX in the serum and the exudate were measured. Peak serum concentrations were obtained at the end of the infusion, with a mean peak level of 97.93 micrograms/ml. Peak concentrations in the exudate were observed 30 to 60 minutes later and varied from 21.10 to 56.25 micrograms/ml. 4. Of the 20 patients administered of CFX, complete clinical and bacteriological data of anaerobic infections were available in 8 patients. The clinical evaluation was 'good' in 7 patients and 'fair' in 1. The bacteriological evaluation was 'eradicated' in 5 patients and 'decreased' in 3. As for side effects, elevations of S-GOT and S-GPT were observed in 4 of the 20 patients received CFX, but these abnormalities might also be attributable to other factors such as underlying disease, surgical intervention etc. No other side effects were found in these patients.

Purification and characterization of polyethylene glycol dehydrogenase involved in the bacterial metabolism of polyethylene glycol

Polyethylene glycol (PEG) dehydrogenase in crude extracts of a PEG 20,000-utilizing mixed culture was purified 24 times by precipitation with ammonium sulfate, solubilization with laurylbetaine, and chromatography with diethylamino-ethyl-cellulose, hydroxylapatite, and Sephadex G-200. The purified enzyme was confirmed to be homogeneous by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The molecular weight of the enzyme, which appeared to consist of four identical subunits, was 2.4 X 10(5). The enzyme was stable below 35 degrees C and in the pH range of 7.5 to 9.0. The optimum pH and temperature of the activity were around 8.0 and 60 degrees C, respectively. The enzyme did not require any metal ions for activity and oxidized various kinds of PEGs, among which PEG 6,000 was the most active substrate. The apparent Km values for tetraethylene glycol and PEG 6,000 were about 10.0 and 3.0 mM, respectively.

Bacterial oxidation of polyethylene glycol

The metabolism of polyethylene glycol (PEG) was investigated with a synergistic, mixed culture of Flavobacterium and Pseudomonas species, which are individually unable to utilize PEGs. The PEG dehydrogenase linked with 2,6-dichlorophenolindophenol was found in the particulate fraction of sonic extracts and catalyzed the formation of a 2,4-dinitrophenylhydrazine-positive compound, possibly an an aldehyde. The enzyme has a wide substrate specificity towards PEGs: from diethylene glycol to PEG 20,000 Km values for tetraethylene glycol (TEG), PEG 400, and PEG 6,000 were 11, 1.7, and 15 mM, respectively. The metabolic products formed from TEG by intact cells were isolated and identified by combined gas chromatography-mass spectrometry as triethylene glycol and TEG-monocarboxylic acid plus small amounts of TEG-dicarboxylic acid, diethylene glycol, and ethylene glycol. From these enzymatic and analytical data, the following metabolic pathway was proposed for PEG: HO(CH2CH2O)nCH2CH2OH leads to HO(CH2CH2O)nCH2CHO leads to HO(CH2CH2O)nCH2COOH leads to HO(CH2CH2O)n-1CH2CH2OH.

Identification and properties of reactive sites in protein capable of binding carbon dioxide in a gas-solid phase system

In order to identify the functional groups which really contribute to the carbon dioxide gas adsorption by proteins, epsilon-amino groups of lysine residues of egg albumin were chemically modified with trinitrobenzene sulfonic acid to various degrees. About 60% of the total amount of carbon dioxide gas absorbed by solid egg albumin diminished by complete modification. The amount of carbon dioxide gas adsorbed by lysozyme, its hydrolyzates and gelatin hydrolyzates depended upon the lysine content, arginine content and average molecular weight. The good correlation was obtained between the amount of carbon dioxide gas absorbed and the total of lysine and arginine content of them. The ability of carbon dioxide gas adsorption by alpha-amino group of amino acids and oligopeptides was found to be developed by the elongation of the peptide chain of glycine and other amino acid, by the removal of alpha-carboxyl group of histidine and tyrosine to corresponding amines and by the esterification of alpha-carboxyl group of leucine with p-nitrophenol. These results clearly indicate that CO2 binding sites in protein in the gas-solid phase system are epsilon-amino, alpha-amino and guanidinium groups.

Carbon dioxide-protein interaction in a gas-solid phase

In the course of developing the packaging of protein foods under the carbon dioxide atmosphere, various proteins in a solid state were found to adsorb carbon dioxide gas gradually. The results obtained by the Warburg manometry indicated that 100-1000 mul of carbon dioxide gas was adsorbed at 25 degrees C for 24 hr by gram of purified proteins, dried protein foods and other proteinous materials such as the rabbit hair and raw silk when they were placed in the high partial pressure of carbon dioxide gas. Casein, gelatin and raw silk were revealed to be the better adsorbents comparing with egg albumin, hemoglobin, gluten and others tested in this experiment. This adsorption was found to be almost specific to carbon dioxide gas. Amount of carbon dioxide gas adsorbed by casein and gelatin depended on the moisture content of them. The lower the moisture is, the greater the adsorption amount of carbon dioxide gas increase. Peptones and partial hydrolyzates of gelatin also showed the adsorbability. Oligo-peptides, amino acids and amines were examined too. Among these, L-lysine (free base), L-arginine (free base), histamine and tyramine adsorbed a large amount of carbon dioxide gas while others failed to do so. Some differences, however, were observed between temperature dependence and reversibility of the carbon dioxide gas adsorption by proteins and those by amines and amino acids (free bases). The mode of interaction between carbon dioxide and protein in a gas-solid phase was discussed comparing with the results obtained in a gas-liquid phase. Large contribution of physical adsorption and less contribution of chemical reaction or chemisorption were assumed in the mode of the carbon dioxide-protein interaction.