Sulfonolipid content of Cytophaga and Flexibacter species isolated from soil and cultured under different nutrient and temperature regimes

1994 ◽  
Vol 40 (2) ◽  
pp. 132-139 ◽  
Author(s):  
R. A. Drijber ◽  
W. B. McGill
Keyword(s):  
Biochemical Marker ◽  
Narrow Range ◽  
Growth Conditions ◽  
Lipid Biomarkers ◽  
Cell Protein ◽  
G Cell ◽  
Temperature Regimes ◽  
Cell Components ◽  
Lipid Phosphate ◽  
Soil Batch

Gliding bacteria of the genera Cytophaga and Flexibacter contain an unusual sulfonolipid in their outer membrane that may be a potential biochemical marker for these organisms in soil. The precision with which a marker provides information about biomass varies with the range in marker content within the cells of the taxon under study. To evaluate this, Cytophaga and Flexibacter spp. were isolated from earthworm fecal pellets and soil, batch cultured with [35S]sulfate, and extracted for lipids. Sulfonolipid S was measured using isotope dilution techniques and lipid phosphate was determined by colorimetry. Ratios of sulfonolipid S to protein and to phospholipid P were compared among isolates grown under various conditions. Ratios of sulfonolipid S to phospholipid P from 0.22 to 0.98 confirmed sulfonolipids as major cell components of Cytophaga and Flexibacter spp. Two criteria essential to the success of sulfonolipids as a biomarker for these organisms in soil were met: (i) sulfonolipid concentration among the noncellulolytic isolates, with one exception, spanned a narrow range (40–60 μmol S/g cell protein), and (ii) this range in sulfonolipid concentration was maintained under the range of growth conditions studied here. Cellulolytic cytophagas, however, could be clearly differentiated from other Cytophaga and Flexibacter spp. on the basis of sulfonolipid content, 85–164 μmol S/g cell protein. This dichotomy in sulfonolipid content between cellulolytic and noncellulolytic isolates must be considered when interpreting data where sulfonolipids are used as a quantitative biomarker for Cytophaga and Flexibacter spp. in habitats where cellulolytic cytophagas are dominant.Key words: lipid biomarkers, cellulolytic cytophagas, Cytophaga, Flexibacter, sulfonolipids.

scholarly journals A model for variable phytoplankton stoichiometry based on cell protein regulation

2013 ◽  
Vol 10 (2) ◽  
pp. 3241-3279
Author(s):  
J. A. Bonachela ◽  
S. D. Allison ◽  
A. C. Martiny ◽  
S. A. Levin
Keyword(s):  
Physiological State ◽  
Single Point ◽  
Nutrient Content ◽  
Growth Conditions ◽  
Marine Phytoplankton ◽  
Cell Protein ◽  
Nitrogen And Phosphorus ◽  
Elemental Ratios ◽  
Regulatory Processes ◽  
Complex Interactions

Abstract. The elemental ratios of marine phytoplankton emerge from complex interactions between the biotic and abiotic components of the ocean, and reflect the plastic response of individuals to changes in their environment. The stoichiometry of phytoplankton is, thus, dynamic and dependent on the physiological state of the cell. We present a theoretical model for the dynamics of the carbon, nitrogen and phosphorus contents of a phytoplankton population. By representing the regulatory processes controlling nutrient uptake, and focusing on the relation between nutrient content and protein synthesis, our model qualitatively replicates existing experimental observations for nutrient content and ratios. The population described by our model takes up nutrients in proportions that match the input ratios for a broad range of growth conditions. In addition, there are two zones of single-nutrient limitation separated by a wide zone of co-limitation. Within the co-limitation zone, a single point can be identified where nutrients are supplied in an optimal ratio. The existence of a wide co-limitation zone affects the standard picture for species competing for nitrogen and phosphorus, which shows here a much richer pattern. However, additional comprehensive laboratory experiments are needed to test our predictions. Our model contributes to the understanding of the global cycles of oceanic nitrogen and phosphorus, as well as the elemental ratios of these nutrients in phytoplankton populations.

Water and Temperature Stress Impact Fitness of Acetohydroxyacid Synthase–Inhibiting Herbicide-Resistant Populations of Eastern Black Nightshade (Solanum ptychanthum)

Weed Science ◽  
2011 ◽  
Vol 59 (3) ◽  
pp. 341-348 ◽  
Author(s):  
Jamshid Ashigh ◽  
François J. Tardif
Keyword(s):  
Seed Production ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Stress Conditions ◽  
Acetohydroxyacid Synthase ◽  
Eastern Black Nightshade ◽  
Black Nightshade ◽  
Reproductive Ability ◽  
Temperature Regimes ◽  
The Impact

Many substitutions in the herbicide target enzyme acetohydroxyacid synthase (AHAS) confer whole-plant resistance and may reduce plant fitness. This study was done to determine the impact of different watering and temperature regimes on the germination, growth, and seed production of eastern black nightshade populations resistant (R) to AHAS inhibitors as conferred by an Ala205Val substitution in their AHAS. Growth and reproductive ability of four R and four susceptible (S) populations were determined in growth-cabinet and greenhouse studies. The R populations had lower total berry and viable seed production per plant than S under optimal conditions because of slower berry maturation. Seed production of both S and R populations decreased under lower or higher than optimal watering regimes; however, this reduction was more pronounced for the S populations so that seed production was comparable across S and R. The R populations had significantly higher germination and vegetative growth under cooler alternating temperature regimes. Although there were no differences between R and S plants under stress conditions, under optimal growth conditions, the Ala205Val substitution comes at a significant cost in eastern black nightshade. Under optimal growth conditions and in the absence of herbicide selection, S populations should eventually dominate over R; however, the lack of fitness differences under stress conditions could enhance the persistence of the R individuals.

Secretion of nascent lipoproteins by isolated rat hepatocytes

1981 ◽  
Vol 59 (8) ◽  
pp. 676-686 ◽  
Author(s):  
Elaine S. Krul ◽  
Peter J. Dolphin ◽  
David Rubinstein
Keyword(s):  
Molecular Weight ◽  
Rat Hepatocytes ◽  
Low Density Lipoproteins ◽  
Cell Protein ◽  
Low Density ◽  
Isolated Rat Hepatocytes ◽  
Apo B ◽  
G Cell ◽  
Apo E ◽  
Isolated Rat

The nature of the nascent lipoproteins secreted by suspensions of isolated rat hepatocytes incubated in a lipid-deficient medium was investigated. Samples of the concentrated medium after 12 and 24 h of incubation were resolved by gel filtration and demonstrated that lipoproteins were secreted with a wide spectrum of particle sizes. Particles corresponding to sizes of serum very low density lipoproteins (VLDL) and low density lipoproteins (LDL) had similar levels of apolipoproteins (apo) B and E as serum VLDL when determined by electroimmunoassay, suggesting that the liver cell secretes a "small" VLDL under these conditions and not an LDL particle as present in the serum. Lipid analyses of the secreted triglyceride-rich particles show them to be similar in composition to serum VLDL with the exception of their cholesterol ester content, which was much lower in the hepatocyte-secreted VLDL. Incorporation of 3H-labelled amino acids into the VLDL apoproteins from the incubation medium after 24 h was determined after ultracentrifugal isolation (d < 1.063 g∙mL−1) and urea–gel electrophoresis, and found to be 70% and 22% of the total applied radioactivity for apo B and apo E, respectively. The lack of immunochemicaily detectable apo C-II and C-III in the isolated nascent VLDL and the lack of significant radioactive incorporation confirmed their visual absence from the gels. Further purification of the VLDL apo E by immunoaffinity chromatography showed it to consist of two narrowly separated bands on 7 M urea – polyacrylamide gels. Apo B was secreted only with particles having mean diameters of greater than 194 Å. In contrast, 75% of the total secreted apo E was associated with fractions of smaller particle diameters. This apo E (LpE) was almost equally distributed in two peaks corresponding to a particle size of approximately 100 Å and a molecular weight of < 60 000, respectively. Only 35% of the total apo E was found in the comparable fractions when hepatocytes from hypercholesterolemic rats were used. Thus, normal hepatocytes secrete a significant proportion of apo E, as a low molecular weight, essentially lipid-free form. The apparent secretion rates, for the apoproteins (mean ± SEM) for hepatocytes from normal rats, were 77.0 + 10.6 μg∙h−1∙g cell protein−1 (apo B) and 71.7 ± 8.6 μg∙h−1∙g cell protein−1 (apo E) after 24 h.

scholarly journals A model for variable phytoplankton stoichiometry based on cell protein regulation

2013 ◽  
Vol 10 (6) ◽  
pp. 4341-4356 ◽  
Author(s):  
J. A. Bonachela ◽  
S. D. Allison ◽  
A. C. Martiny ◽  
S. A. Levin
Keyword(s):  
Physiological State ◽  
Single Point ◽  
Nutrient Content ◽  
Growth Conditions ◽  
Marine Phytoplankton ◽  
Cell Protein ◽  
Nitrogen And Phosphorus ◽  
Elemental Ratios ◽  
Regulatory Processes ◽  
Complex Interactions

Abstract. The elemental ratios of marine phytoplankton emerge from complex interactions between the biotic and abiotic components of the ocean, and reflect the plastic response of individuals to changes in their environment. The stoichiometry of phytoplankton is, thus, dynamic and dependent on the physiological state of the cell. We present a theoretical model for the dynamics of the carbon, nitrogen and phosphorus contents of a phytoplankton population. By representing the regulatory processes controlling nutrient uptake, and focusing on the relation between nutrient content and protein synthesis, our model qualitatively replicates existing experimental observations for nutrient content and ratios. The population described by our model takes up nutrients in proportions that match the input ratios for a broad range of growth conditions. In addition, there are two zones of single-nutrient limitation separated by a wide zone of co-limitation. Within the co-limitation zone, a single point can be identified where nutrients are supplied in an optimal ratio. When different species compete, the existence of a wide co-limitation zone implies a more complex pattern of coexistence and exclusion compared to previous model predictions. However, additional comprehensive laboratory experiments are needed to test our predictions. Our model contributes to the understanding of the global cycles of oceanic nitrogen and phosphorus, as well as the elemental ratios of these nutrients in phytoplankton populations.

Photoluminescence Study of Chloride Vpe-Grown Gan

1996 ◽  
Vol 421 ◽  
Author(s):  
Tetsuzo Ueda ◽  
Masaaki Yuri ◽  
Heon Lee ◽  
James S. Harris ◽  
Takaaki Baba
Keyword(s):  
Growth Temperature ◽  
Narrow Range ◽  
Rough Surfaces ◽  
Three Dimensional ◽  
Growth Conditions ◽  
Deep Acceptor ◽  
Flat Surfaces ◽  
Donor Acceptor ◽  
Dimensional Growth ◽  
Source Materials

AbstractWe have examined the effect of growth conditions on photoluminescence (PL) characteristics of chloride VPE-grown GaN films. Undoped GaN films are grown on sapphire by a newly developed chloride VPE system which utilizes GaCl3 and NH3 as source materials.We find that the spectra depend strongly on the growth temperatures and the corresponding surface morphology. Peaks from excitons and donor-acceptor pairs (D-A pair) recombination are observed for the films with terrace-like flat surfaces grown at between 950°C and 1000°C. A peak due to exciton bound to neutral donors is observed for a growth temperature of 975°C where the acceptor-related peaks are not seen. Decreasing the growth temperature below 950°C causes rough surfaces due to three-dimensional growth, whereas increasing the growth temperature above 1000°C causes cracks or partial pealing off of the film. The films with rough surfaces or crystal failures show broad emission from deep acceptor levels. As a result, residual acceptors are eliminated in the very narrow range of the growth temperature around 975°C. It is also noted that an increase of the V/III ratio during the growth makes the line width of the band-edge peak narrower. The PL results show that a growth temperature around 975°C and high V/III ratio are essential to obtain better crystal quality and reduced concentration of residual acceptors.

The sedimentation of buoyant Microcystis colonies caused by precipitation with an iron-containing colloid

1985 ◽  
Vol 223 (1233) ◽  
pp. 511-528 ◽  
Keyword(s):  
Turgor Pressure ◽  
Sediment Traps ◽  
Cell Protein ◽  
Gas Vesicles ◽  
Lake District ◽  
Dissolved Iron ◽  
Inorganic Matter ◽  
Cell Turgor ◽  
Cell Components ◽  
Bottom Mud

Colonies of Microcystis aeruginosa have dominated the phytoplankton in Lund tube C, a limnetic enclosure in Blelham Tarn, English Lake District, during the summer and autumn in recent years. Following holomixis in autumn the previously buoyant colonies sedimented from the water column onto the bottom mud. In all samples gas vesicles, which provided the colonies with buoyancy, were present in sufficient volume to negate the combined ballast provided by protein, carbohydrate, lipid and phosphate, the major cell components. The gas vesicles, which accounted for about 10% of the cell protein, were too strong to be collapsed or regulated by cell turgor pressure. Consequently, the loss of buoyancy could not be explained by an increase in cell ballast or by disappearance of gas vesicles. Colonies collected in sediment traps were found to be buoyant after they had been agitated and diluted with lake water, which removed a colloidal precipitate from them. Similarly, 66% of the sinking fraction of a net tow sample was found to be buoyant after it had been treated in the same way. Previously buoyant colonies could be made to sink on mixing with the colloidal precipitate. This demonstrated the ability of the precipitate to trap colonies and to cause their sedimentation. The colloid comprised approximately equal amounts of organic and inorganic matter and was rich in iron. Colloids of this type form when the dissolved iron in the anoxic water of the hypolimnion becomes oxidized on mixing with the aerated water of the epilimnion.

Growth of SiC Boules with Low Boron Concentration

2006 ◽  
Vol 527-529 ◽  
pp. 47-50 ◽  
Author(s):  
Mark A. Fanton ◽  
R.L. Cavalero ◽  
R.G Ray ◽  
B.E. Weiland ◽  
W.J. Everson ◽  
...  
Keyword(s):  
High Purity ◽  
Pyrolytic Graphite ◽  
Growth Conditions ◽  
Hydrogen Gas ◽  
Boron Diffusion ◽  
Growth Environment ◽  
Carbide Coatings ◽  
Cell Components ◽  
Site Competition ◽  
Graphite Growth

The effects of growth conditions, diffusion barrier coatings, and hot zone materials on B incorporation in 6H-SiC crystals grown by physical vapor transport (PVT) were evaluated. Development of high purity source material with a B concentration less than 1.8x1015 atoms/cm3, was critical to the growth of boules with a B concentration less than 3.0x1016 atoms/cm3. Application of refractory metal carbide coatings to commercial graphite to serve as boron diffusion barriers and the use of very high purity pyrolytic graphite components ultimately led to the growth of SiC boules with boron concentrations as low as 2.4x1015 atoms/cm3. The effect of growth temperature and pressure were closely examined over a range from 2100°C to 2300°C and 5 to 13.5 Torr. This range of growth conditions and growth rates had no effect on B incorporation. Attempts to alter the gas phase stoichiometry through addition of hydrogen gas to the growth environment also had no impact on B incorporation. These results are explained by considering site competition effects and the ability of B to diffuse through the graphite growth cell components.

Fermentation of lactose by Bacteroides polypragmatus

1983 ◽  
Vol 29 (1) ◽  
pp. 120-128 ◽  
Author(s):  
G. B. Patel
Keyword(s):  
Growth Conditions ◽  
Cell Protein ◽  
Mineral Salts ◽  
Batch Cultures ◽  
Cell Biomass ◽  
Lactose Fermentation ◽  
Substrate Conversion ◽  
Lag Period ◽  
Lactose Utilization ◽  
Potential Use

Lactose fermentation by the mesophilic anaerobic bacterium Bacteroides polypragmatus was studied in 100-mL batch cultures using a mineral salts – vitamin medium containing 0.4% (w/v) yeast extract and cysteine-Na2S reducing agent. Bacteroides polypragmatus could be cultivated in the presence of initial lactose concentrations as high as 20.0% (w/v). However, at these levels, the lag period was approximately 12 h compared with less than 6 h in media containing up to 5.0% lactose. Optimum growth and substrate conversion to H2 was obtained in medium supplemented with 1.5–2.0% lactose. Under these growth conditions, the metabolic end products (moles per mole of lactose) after 48 h of incubation were 3.33 H2, 4.20 CO2, 1.82 ethanol, 1.46 acetic acid, and 0.06 butyric acid. The growth rate in approximately 2.0% (w/v) glucose or galactose medium (μ = 0.23 h−1) was higher than that (μ = 0.14 h−1) in lactose. The maximum rate of glucose and lactose utilization was 6.3 and 3.8 g∙L−1∙24 h−1, respectively. The maximum lactase in lactose-grown culture was about twice that of galactose-cultivated cells, and the activity in glucose culture was negligible. The results indicate that B. polypragmatus may be of potential use in the disposal of lactose, since besides H2, the cell biomass (approximately 35% cell protein) may also prove to be a useful by-product.

A type I cell-specific protein is a biochemical marker of epithelial injury in a rat model of pneumonia

1995 ◽  
Vol 268 (2) ◽  
pp. L181-L186 ◽  
Author(s):  
M. C. McElroy ◽  
J. F. Pittet ◽  
S. Hashimoto ◽  
L. Allen ◽  
J. P. Wiener-Kronish ◽  
...  
Keyword(s):  
Cell Injury ◽  
Biochemical Marker ◽  
Specific Protein ◽  
Cell Protein ◽  
Morphological Evidence ◽  
Type I ◽  
Lactate Dehydrogenase Activity ◽  
Epithelial Injury ◽  
Fluid Content ◽  
Alveolar Epithelial

In this study we determined whether the alveolar fluid content of a specific epithelial type I cell protein, rTI40, can be used as a biochemical marker for lung injury. A model of alveolar epithelial injury was developed by instilling Pseudomonas aeruginosa bacteria (PA103) into the airspaces of anesthetized, ventilated rats. After 6 h, the alveolar fluid content of rTI40 from PA103-treated rats was increased over 80-fold in comparison to alveolar fluid from control rats (P < 0.05). This increase in rTI40 correlated with both morphological evidence of injury to alveolar epithelial type I cells and increased permeability of the alveolar epithelium to protein tracers. In contrast, the lactate dehydrogenase activity of alveolar fluid from PA103-treated rats was elevated only threefold over control values at 6 h (P < 0.05). In a second study using a less injurious strain of P. aeruginosa (PA103 exsA::omega), the alveolar fluid content of rTI40 was the same as control values. These findings indicate that the alveolar fluid content of a type I cell-specific protein can be used as a sensitive and specific biochemical marker of type I cell injury.

Ultrastructure of Giant Mitochondria and Their Inclusions in Schwann Cells of Bovine Splenic Nerve

1974 ◽  
Vol 32 ◽  
pp. 194-195
Author(s):  
Å. Thureson-Klein
Keyword(s):  
Schwann Cells ◽  
Cell Organelles ◽  
Giant Mitochondria ◽  
Matrix Density ◽  
Physiological Conditions ◽  
Unmyelinated Axons ◽  
Internal Structures ◽  
Structural Abnormalities ◽  
Cytotoxic Compounds ◽  
Cell Components

Giant mitochondria of various shapes and with different internal structures and matrix density have been observed in a great number of tissues including nerves. In most instances, the presence of giant mitochondria has been associated with a known disease or with abnormal physiological conditions such as anoxia or exposure to cytotoxic compounds. In these cases degenerative changes occurred in other cell organelles and, therefore the giant mitochondria also were believed to be induced structural abnormalities.Schwann cells ensheating unmyelinated axons of bovine splenic nerve regularly contain giant mitochondria in addition to the conventional smaller type (Fig. 1). These nerves come from healthy inspected animals presumed not to have been exposed to noxious agents. As there are no drastic changes in the small mitochondria and because other cell components also appear reasonably well preserved, it is believed that the giant mitochondria are normally present jin vivo and have not formed as a post-mortem artifact.

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