[Use of flame emission analysis for measuring the alkaline cation flux across a cell membrane]

Concentration-emission relations are presented for assayed alkaline cations within 1-100 micro M and interfering alkaline cations at concentrations 1-150 mM. All the data were obtained with the Perkin-Elmer AA spectrophotometer (AA 306) and with an air-propane flame. The advantages of flame-emission technique for measurements of cation fluxes across cell membrane are demonstrated on frog muscle and neuroblastoma cells.

Pseudomonas aeruginosa bacteriophage phi PLS27-lipopolysaccharide interactions

We investigated the phi PLS27 receptor in Pseudomonas aeruginosa strain PAO lipopolysaccharide (LPS) by analyzing a resistant mutant. This mutant, which was designated AK1282, had the most defective LPS yet reported for a P. aeruginosa rough mutant; this LPS contained only lipid A, 2-keto-3-deoxyoctonate, heptose, and alanine as major components. In addition, this LPS lacked galactosamine, which is present in the inner core of the LPS of other rough mutants. The loss of galactosamine but only a small decrease in the alanine content indicated that the core of strain PAO LPS differed from the core structure which has been suggested for the LPS of other well-characterized P. aeruginosa strains. Our analysis also indicated that galactosamine residues may be crucial for phi PLS27 receptor activity of the LPS. Electrodialysis of LPS and conversion to salt forms (sodium or triethylamine) influenced the phage-inactivating capacity of the LPS, as did the medium in which the inactivation occurred; experiments performed in 1/10-strength broth resulted in much lower PhI50 (concentration of LPS causing a 50% decrease in the titer of phage during 1 h of incubation at 37 degrees C) values than experiments performed in regular-strength broth. Sonication of the LPS also increased the phage-inactivating capacities of the LPS preparations.

Subcellular distribution of ionic components in gastric mucosa of the guinea pig

The topographical distribution of cations, anions and polyanions in the guinea-pig stomach has been studied by ultrastructural cytochemical methods. After fixation with the pyroantimonate-osmium tetroxide solution, variable-sized precipitates were localized in the basolateral extracellular space bordering parietal cells or chief cells but not in that bordering mucus-secreting cells. The basal lamina of all gastric cells disclosed a continuous layer of heavy antimonate deposits. Parietal cells disclosed uniformly fine deposits also on the apical plasmalemma both at the main lumen and in the intracellular canaliculi, and revealed, as well, coarse precipitates in the mitochondria. Fixation with a silver acetate-osmium tetroxide solution yielded nitric acid-resistant, silver deposits confined to the luminal surface of the apical plasmalemma in the main lumen and intracellular canaliculi, the lateral intercellular space, the outer surface of the basal plasmalemma and the basal lamina of the parietal cell. Staining with dialyzed iron demonstrated a glycocalyx rich in acid mucosubstance on the basolateral plasmalemma but not on the apical plasmalemma of parietal cells. In contrast, acid glycoconjugate was visualized on the apical plasmalemma of isthmus cells, mucous neck cells and the transitional cell between isthmus and mucous neck cells but little or no acidic glycoconjugate was demonstrated on the basolateral plasmalemma of these cells. The entire plasmalemma of gastroendocrine cells, unlike other epithelial cells, stained uniformly for acidic glycoconjugate. The dialyzed iron and high iron diamine methods stained the outer compartment of mitochondria in parietal cells intensely and that in other gastric cells lightly. These reagents stained the basal lamina of all gastric cells as did ruthenium red. The several characteristic cytochemical properties of parietal cells presumably relate to the unique secretory activity of these cells and are consistent with the view of the intracellular canaliculi of the parietal cell as the main route for hydrogen and chloride in secretion.

Physicochemical speciation of lead in drinking water

Recent studies have highlighted the importance of drinking water as a route of human exposure to lead. Whilst there are ample data on lead concentrations in drinking water, little is known of its physical and chemical forms (physicochemical speciation). Such information is important as the speciation of ingested lead influences the efficiency of absorption from the gastrointestinal tract. Knowledge of speciation should also provide a fuller understanding of the factors controlling the solubility of lead in potable waters and hence assist in devising the most cost-effective means of plumbosolvency control. We have determined experimentally the speciation of lead in three different tapwaters and report here diverse forms of dissolved and particle-associated lead, dependent primarily on the chemical matrix of the raw water.

Cation components of Mueller-Hinton agar affecting testing of Pseudomonas aeruginosa susceptibility to gentamicin

Seven lots of Mueller-Hinton agar were examined for calcium and magnesium contents and their distribution in pools or compartments. Gel disruption and centrifugation yielded the soluble cations, which varied from 9 to 113% of the total calcium and from 76 to 102% of the total magnesium. Throughout the experiments, a standardized disk diffusion test, using Pseudomonas aeruginosa (ATCC 27852) and a 10-mug gentamicin disk, served as an indicator for medium performance. Zone diameters correlated well with the sums of the soluble calcium and magnesium values in the different lots (r = -0.85). Ionized calcium, presumably the biologically active ion, was measured with a calcium-specific electrode. It represented only a fraction of the soluble calcium pool in three lots. Autoclaving resulted in shifts of the cations between the different pools. Addition of magnesium to one medium lot resulted in shifts of soluble and ionized calcium, indicating an interdependence of calcium and magnesium, and zone diameters correlated with soluble magnesium (r = -0.98), soluble calcium (r = -0.96), and ionized calcium (r = -0.96) in this experiment. Manipulation of one medium to match the performance of another showed that excess amounts of both ions were required to obtain similar performance. Satisfactory performance of an individual medium can be obtained by cation supplementation, but simple adjustment will not suffice for all media. The interaction of the other cation pool components must also be evaluated.

Cationic composition of 22 species of bacteria grown in seawater medium

Twenty-two species of bacteria of marine, estuarine, and terrestrial origin were analyzed for cationic content by atomic absorption spectrophotometry after growth in a basal seawater medium. Alcaligenes marinus was analyzed from eight separate but replicate determinations yielding the following cationic concentrations: Na, 5,600 +/- 2,260; Mg 1,580 +/- 740; K, 700 +/- 360; Ca, 790 +/- 390; Mn, 1.7 +/- 0.5; Fe, 256 +/- 57; Ni, 1.7 +/- 0.7; Cu, 14 +/- 4; Zn, 122 +/- 27; Cd, 2.8 +/- 0.7; and Pb, 10 +/- 3 ppm/(dry weight). Washing A. marinus cells before analyses was necessary due to interstitial medium within the cell pellets after centrifugation and loose cationic retention by the cells. The principal source of error in the procedure was ascribed to variability due to washing cells with 0.5 M ammonium formate. The mean cationic concentrations for trace elements in the 22 bacterial cultures grown in the basal seawater medium to constant optical density and washed three times with 0.5 M ammonium formate were: Mn, 2.4 +/- 3.8; Fe, 262 +/- 112; Ni, 2.3 +/- 1.8; Cu, 24 +/- 17; Zn, 146 +/- 72; Cd, 3.8 +/- 2.5; and Pb, 17 +/- 21 ppm (dry weight). Major ions were concentrated only occasionally by the cells after washing, whereas Mn, Fe, Ni, Cu, Zn, Cd, and Pb were concentrated from the medium by the following factors on the average: 180, 1,600, 140, 1,200, 750, 1,900, and 900, respectively.

The effect of a natural high-fiber diet on serum lipids, fecal lipids, and colonic function

In a cross-over experiment, 46 young healthy volunteers consumed in succession a high-fiber and a low-fiber diet for 3 weeks at two levels of dietary cholesterol. Half of the dietary fiber came from fruits and vegetables, and the rest from bread and other cereal products. On the high-fiber diet, concentrations of serum cholesterol decreased on average by 0.44 mmole/liter with high-cholesterol and 0.31 mmole/liter with low-cholesterol regimes; high density lipoprotein-cholesterole decreased by 0.1 mmole/liter; on average fecal weight increased by 115 g/day and mean transit time through the gut was decreased by 18 hr. Only part of the decrease in serum cholesterole may be due directly to the high intake of dietary fiber components. The remainder is due to differences in fat intake: during the high-fiber period subjects consumed less fat and cholesterol than had been planned.

Some inorganic constituents of the subretinal fluid

The inorganic constituents of the subretinal fluid (SRF) were analyzed using atomic absorption spectrometry. Four main elements (Na, K, Ca, Mg) were determined in 41 samples; Cu was determined in 36 samples and Zn in 24 samples. The results are presented graphically, taking into account the concentrations of each element in the SRF and the number of cases. In 9 cases, the concentrations of the inorganic elements were also determined in blood serum; it was established that the SRF is richer in Mg than blood serum and poorer in the other elements. No correlation was found between the concentration of the inorganic elements in the SRF and the clinical picture of retinal detachment.

Morphine depression and tolerance of nerve-induced parotid secretion

1 The nerve-induced secretion produced by the rat parotid gland is proportional to the frequency of stimulation. Morphine decreased the flow rate during stimulation at 2.5 and 5 Hz, but not at 20 Hz. This frequency-dependent action of morphine and was partially reversed by naloxone. 2 The secretion produced by the rat parotid gland during an intravenous infusion of acetylcholine was not diminished by morphine. Therefore, the action of morphine on nerve-induced secretion is most probably on the motor nerve terminals, which release acetylcholine. 3 Animals that had been implanted with morphine base pellets tolerated 4 times as much morphine as controls; after 6 days the minute ventilation was less depressed by graded doses of morphine than non-implanted controls. 4 Nerve-induced secretion in morphine-implanted animals was less depressed by morphine than control animals 6 and 24 h after the pellets were removed. The flow rates in the 6 h group treated with morphine were greater after naloxone than control (precipitated withdrawal) but at 24 h when withdrawal symptoms were no longer evident, naloxone produced only a slight reversal.

An ultramicro method for analysis of lithium and other biologically important cations

A new method for Li+ analysis by flameless atomic absorption spectroscopy is several orders of magnitude more sensitive than previous methods. Li+ quantities as small as 1 - 10(-12) mol, or Li+ concentrattions as low as 1 - 10(-8) M, can determined with a coeffient of variation of 2--4%. The same technique can determine approx. 1 - 10(-14) mol of Ca2+ and Mg2+, and approx. 1 - 10(-13) mol of Na+ and K+.

Chemical composition of the peptidoglycan-free cell walls of methanogenic bacteria

Cell walls were prepared from freeze-dried samples of 7 strains of Methanobacterium by mechanical disintegration of the cells followed by incubation with trypsin. Electron microscopy revealed the presence of sacculi exhibiting the shape of the original cells, on which no surface structure could be detected. Ultrathin sections of the isolated sacculi showed a homogenously electron dense layer of about 10--15 nm in width. The ash content varied between 8 and 18% of dry weight. The sacculi of all the strains contained Lys: Ala:Glu:GlcNAc or GalNAc in a molar ratio of about 1:1.2:2:1. In one strain (M. ruminantium M1) alanine is replaced by threonine, however, Neutral sugars and--in some strains--additional amounts of the amino sugars were present in variable amounts, and could be removed by formamide extraction or HF treatment without destroying the sacculi. No muramic acid or D-amino acids typical of peptidoglycan were found. Therefore, the sacculi of the methanobacteria consist of a different polymer containing a set of three L-amino acids and one N-acetylated amino sugar. From cells of Methanospirillum hungatii no sacculi, but tube-like sheaths could be isolated, which tend to fracture perpendicularly to the long axis of the sheath along the fibrills seen on the surface. The sheaths consist of protein containing 18 amino acids and small amounts of neutral sugars. They are resistent to the proteinases tested and are not disintegrated by boiling in 2% sodium dodecylsulfate for 30 min. The three Gram-negative strains Black Sea isolate JR-1, Cariaco isolate JR-1 and Methanobacterium mobile do not contain a rigid sacculus, but merely a SDS-sensitive surface layer composed of regularly arranged protein subunits. This evidence indicates that, within the methanogens, different cell wall polymers characteristic of particular groups of organisms may have evolved during evolution, and supports the hypothesis that the evolution of the methanogens was separated from that of the peptidoglycan-containing procaryotic organisms at a very early stage.

[The application of numerical toxonomy for the classification of wines (author's transl)]

Monovariate and multivariate methods for clustering of wines according to origin, grape variety and vintage year (representing) climate are compared. The multivariate method which is described makes it possible to find similarities especially related to origin and is superior to a monovariate analysis.

Elemental distribution in striated muscle and the effects of hypertonicity. Electron probe analysis of cryo sections

A method of rapid freezing in supercooled Freon 22 (monochlorodifluoromethane) followed by cryoultramicrotomy is described and shown to yield ultrathin sections in which both the cellular ultrastructure and the distribution of diffusible ions across the cell membrane are preserved and intracellular compartmentalization of diffusabler ions can be quantitated. Quantitative electron probe analysis (Shuman, H., A.V. Somlyo, and A.P. Somlyo. 1976. Ultramicros. 1:317-339.) of freeze-dried ultrathin cryto sections was found to provide a valid measure of the composition of cells and cellular organelles and was used to determine the ionic composition of the in situ terminal cisternae of the sarcoplasmic reticulum (SR), the distribution of CI in skeletal muscle, and the effects of hypertonic solutions on the subcellular composition if striated muscle. There was no evidence of sequestered CI in the terminal cisternae of resting muscles, although calcium (66mmol/kg dry wt +/- 4.6 SE) was detected. The values of [C1](i) determined with small (50-100 nm) diameter probes over cytoplasm excluding organelles over nuclei or terminal cisternae were not significantly different. Mitochondria partially excluded C1, with a cytoplasmic/ mitochondrial Ci ratio of 2.4 +/- 0.88 SD. The elemental concentrations (mmol/kg dry wt +/- SD) of muscle fibers measured with 0.5-9-mum diameter electron probes in normal frog striated muscle were: P, 302 +/- 4.3; S, 189 +/- 2.9;C1, 24 +/- 1.1;K, 404 +/- 4.3, and Mg, 39 +/- 2.1. It is concluded that: (a) in normal muscle the "excess CI" measured with previous bulk chemical analyses and flux studies is not compartmentalized in the SR or in other cellular organelles, and (b) the cytoplasmic C1 in low [K](0) solutions exceeds that predicted by a passive electrochemical distribution. Hypertonic 2.2 X NaCl, 2.5 X sucrose, or 2.2 X Na isethionate produced: (a) swollen vacuoles, frequently paired, adjacent to the Z lines and containing significantly higher than cytoplasmic concentrations of Na and Cl or S (isethionate), but no detectable Ca, and (b) granules of Ca, Mg, and P = approximately (6 Ca + 1 Mg)/6P in the longitudinal SR. It is concluded that hypertonicity produces compartmentalized domains of extracellular solutes within the muscle fibers and translocates Ca into the longitudinal tubules.