Enhancement of adhesion of the marine Chlorella vulgaris to glass

1975 ◽  
Vol 21 (7) ◽  
pp. 1025-1031 ◽  
Author(s):  
T. R. Tosteson ◽  
W. A. Corpe

The adhesion of washed cells of a marine Chlorella vulgaris to solid surfaces was enhanced by non-diffusible material recovered from Chlorella exudate, marine bacterial cultures, natural seawater, and fouled marine surfaces. Materials isolated from certain bacterial cultures and from particulate materials filtered from seawater were three orders of magnitude more active than Chlorella exudate per unit weight. Active polymer materials from several sources were chromatographed on DEAE cellulose. The major fraction eluted with dilute base contained both protein and carbohydrate and enhanced adhesion more than the unchromatographed material.

2013 ◽  
Vol 25 (6) ◽  
pp. 1687-1695 ◽  
Author(s):  
M. Sirmerova ◽  
G. Prochazkova ◽  
L. Siristova ◽  
Z. Kolska ◽  
T. Branyik

1977 ◽  
Vol 44 (1) ◽  
pp. 63-68 ◽  
Author(s):  
F. Addeo ◽  
J.-M. Chobert ◽  
B. Ribadeau-Dumas

SummaryWhen whole caseins from cow and Italian buffalo (Bubalus arnee) were fractionated by chromatography on a column of hydroxyapatite they behaved in a similar manner. κ-Casein was eluted with 5 mM phosphate buffer, pH 6·8, containing 0·2 M-KCI, 4·5 M-urea and 2 mM-2-mercaptoethanol, but β- and αs-caseins were retained and could be eluted successively by a linear gradient from 5 mM to 250 mMphosphate buffer. Buffalo κ-casein preparations, obtained from bulk milk or from milks of individual animals by chromatography on hydroxyapatite, produced identical electrophoretic patterns at pH 8·6. By further fractionation of these κ-caseins on DEAE-cellulose, in each case, at least 7 components were purified; they had different electrophoretic mobilities but were all sensitive towards chymosin. The major fraction migrated like component 1 of bovine κ-casein B.


Author(s):  
Kristian Haraldsen

The oil and gas industry is moving to deeper water developments and thermal insulation of pipelines at 2–3000 meter water depths is required. Wet thermal insulation systems are exposed directly to the seawater and large hydrostatic water pressure in combination with high fluid temperatures challenge the integrity of the insulation systems. The thermal insulation properties of the insulation system can be gradually decreased by thermal and physical strains and challenge the flow assurance if not taken into account in the design. Wet thermal insulation systems have traditionally been qualified for long term use by a combination of long-term small scale aging tests and shorter term full scale simulated service tests (typically 7–28 days). To evaluate the long performance, simulated service tests have been run for one full year at high water pressure and internal pipe temperatures. A selection of commercially available wet insulation systems have been tested together with system specific field joint coatings under the maximum internal pipe temperature specified for the individual coating systems. The test has been run in natural seawater at 300 barg pressure and temperature of 2–4 °C. The coating thicknesses have been selected to give U-values of 3–4 W/(m2K). Before the simulated service testing all test pipes were run through a simulated reel installation to impose realistic strains on the coating systems before testing. All tested coatings performed according to expectations during the simulated service test. The syntactic systems (PP and PU based) gave gradual decrease in thermal insulation efficiency with time but the reduction was close to linear and can be accounted for in the design. The coating systems based on solid polymer materials did not show the same reduction of thermal insulation properties with time. Tests of natural cool-down performance of the insulated test pipes showed that the cool down times were maintained during the one year simulated service tests. Post-test investigations of the insulation materials did not reveal significant degradation of the materials as result of the tests but coating systems application related defects were identified which had developed over the test period. None of the pre-existing defects developed to such an extent as to affect the overall U-value of the coating system.


1969 ◽  
Vol 115 (3) ◽  
pp. 395-403 ◽  
Author(s):  
R. J. Avery ◽  
J. E. M. Midgley ◽  
G. H. Pigott

From analyses of the hybridization of Escherichia coli rRNA (ribosomal RNA) to homologous denatured DNA, the following conclusions were drawn. (1) When a fixed amount of DNA was hybridized with increasing amounts of RNA, only 0·35±0·02% of E. coli DNA was capable of binding (16s+23s) rRNA. Although preparations of 16s and 23s rRNA were virtually free from cross-contamination, the hybridization curves for purified 16s or 23s rRNA were almost identical with that of the parent specimen containing 1 weight unit of 16s rRNA mixed with 2 weight units of 23s rRNA. The 16s and 23s rRNA also competed effectively for the same specific DNA sites. It appears that these RNA species each possess all hybridizing species typical of the parent (16s+23s) rRNA specimen, though probably in different relative amounts. (2) By using hybridization-efficiency analysis of DNA–RNA hybridization curves (Avery & Midgley, 1969) it was found that (a) 0·45% of the DNA would hybridize total rRNA and (b) when so little RNA was added to unit weight of DNA that the DNA sites were not saturated, only 70–75% of the input RNA would form hybrids. The reasons for the discrepancy between the results obtained by the two alternative analytical approaches were discussed. (3) For either 16s or 23s rRNA, hybridization analysis indicated that two principal weight fractions of rRNA may exist, hybridizing to two distinct groups of DNA sites. However, these groups seem to be incompletely divided between the 16s and 23s fractions. Analysis suggested that (a) 85% of the 16s rRNA was hybridized to about half the DNA that specifically binds rRNA (0·23% of the total DNA). (b) 70% of the 23s rRNA hybridized to a further 0·23% of the DNA and (c) the minor fraction (15%) of 16s rRNA may be competitive with the major fraction (70%) of 23s rRNA. Conversely, the minor fraction (30%) of the 23s rRNA may compete with the major fraction (85%) of 16s rRNA. Models were proposed to explain the apparent lack of segregation of distinct RNA species in the two subfractions of rRNA. (4) If protein synthesis and ribosome maturation were inhibited in cells of an RCrel mutant, E. coli W 1665, by depriving them of an amino acid (methionine) essential for growth, the inhibition had no discernible effect on the relative rates of synthesis of rRNA species. The rRNA that accumulates in RCrel strains of E. coli after amino acid deprivation is apparently identical in its content of RNA species with that of the pre-existing mature RNA in the ribosomes. On the other hand, the messenger RNA is stabilized, and accumulates as about 15% of the RNA formed after withdrawal of the amino acid.


2021 ◽  
Vol 83 (2) ◽  
pp. 51-63
Author(s):  
D.R. Abdulina ◽  
◽  
A.I. Chuenko ◽  
A.S. Topchiy ◽  
G.E. Kopteva ◽  
...  

Polymer materials are an integral part of our lives, but their use is a global environmental problem. Despite this, the development of modern approaches to the utilization of used polymer and rubber materials is currently relevant, including the using of anaerobic microbial destruction of polymers by sulfatereducing bacteria. The aim of the work. To study the ability of sulfate-reducing bacteria to utilize rubber and polymer materials such as solid rubber, ethylene vinyl acetate and foamed polyethylene. Methods. Microbiological (cultivation of sulfate-reducing bacteria, method of serial dilutions), biochemical (Lowry method, measurement of enzymatic activity), physical and chemical (gravimetry, iodometry, potentiometry, gas chromatography-mass spectrometry). Results. It was shown that in the presence of the studied materials as the sole sources of carbon, the amount of sulfate-reducing bacteria increased by 2–3 orders compared to the control without adding the materials. On the 90th day of the experiment the destruction coefficients of the studied materials were low and reached KD=0.21–2.88%. In the cultivation medium with the introduced studied materials, the metabolic and enzymatic activity of sulfate-reducing bacteria are changed, in particular, the production of hydrogen sulfide in the presence of ethylene vinyl acetate and foamed polyethylene increased by 0.8–3 times, and rubber – decreased by 1.2–3.5 times. The catalase activity of the studied bacterial cultures was decreased by 1.4–3.4 times compared to the control without adding of materials. During the exposure period with adding the materials, the lipase activity of bacterial cultures decreased and in some cases almost disappeared. The introduction of materials led to increasing of the short-chain fatty acids synthesis by Desulfovibrio desulfuricans DSM642 and D. vulgaris DSM644 strains, while, on the contrary, Desulfovibrio sp. 10 strain showed the decreasing in acid production. The introduction of rubber only in D. vulgaris DSM644 culture leads to the increasing of acetic and propanoic acids synthesis by 59% and 49.5%, respectively, compared to the control without the introduction of the studied materials. The synthesis of acetic acid in the presence of foamed polyethylene and ethylene vinyl acetate in the cultural liquid of sulfate-reducing bacteria increased by 46.2–419.5% and 69.8–92.6%, and propane – by 23.1–46.2% and 71.9–159.0%, respectively. Conclusions. The presence in cultivation media of rubber, foamed polyethylene and ethylene vinyl acetate as a sole carbon sources led to the changes in enzymatic activity (catalase and lipase), the intensification of hydrogen sulfide synthesis by bacteria was observed as well as acetic, propanoic and butanoic acids synthesis increased. This indicates the potential of sulfate-reducing bacteria to utilize the studied materials via acid formation.


1978 ◽  
Vol 48 ◽  
pp. 155-166 ◽  
Author(s):  
A. N. Argue ◽  
E. D. Clements ◽  
G. M. Harvey ◽  
C. A. Murray

SummaryAGK3-based optical positions are presented for 38 counterparts of radio sources selected from the catalogue of Elsmore & Ryle. The measurements were made from plates taken with the 13-inch Astrograph, the 26-inch refractor and the 2.5 m (INT) reflector at Herstmonceux, and the 17-inch Schmidt at Cambridge. The standard error for a mean position of unit weight is 0”.11, and the weights range from 3.0 for the brightest sources to 0.5 for the faintest. Comparison with the radio positions shows no significant differences. The effects of applying the Brorfelde corrections to AGK3 are discussed.


Author(s):  
D.T. Grubb

Diffraction studies in polymeric and other beam sensitive materials may bring to mind the many experiments where diffracted intensity has been used as a measure of the electron dose required to destroy fine structure in the TEM. But this paper is concerned with a range of cases where the diffraction pattern itself contains the important information.In the first case, electron diffraction from paraffins, degraded polyethylene and polyethylene single crystals, all the samples are highly ordered, and their crystallographic structure is well known. The diffraction patterns fade on irradiation and may also change considerably in a-spacing, increasing the unit cell volume on irradiation. The effect is large and continuous far C94H190 paraffin and for PE, while for shorter chains to C 28H58 the change is less, levelling off at high dose, Fig.l. It is also found that the change in a-spacing increases at higher dose rates and at higher irradiation temperatures.


Author(s):  
J. Petermann ◽  
G. Broza ◽  
U. Rieck ◽  
A. Jaballah ◽  
A. Kawaguchi

Oriented overgrowth of polymer materials onto ionic crystals is well known and recently it was demonstrated that this epitaxial crystallisation can also occur in polymer/polymer systems, under certain conditions. The morphologies and the resulting physical properties of such systems will be presented, especially the influence of epitaxial interfaces on the adhesion of polymer laminates and the mechanical properties of epitaxially crystallized sandwiched layers.Materials used were polyethylene, PE, Lupolen 6021 DX (HDPE) and 1810 D (LDPE) from BASF AG; polypropylene, PP, (PPN) provided by Höchst AG and polybutene-1, PB-1, Vestolen BT from Chemische Werke Hüls. Thin oriented films were prepared according to the method of Petermann and Gohil, by winding up two different polymer films from two separately heated glass-plates simultaneously with the help of a motor driven cylinder. One double layer was used for TEM investigations, while about 1000 sandwiched layers were taken for mechanical tests.


Author(s):  
W. A. Chiou ◽  
N. Kohyama ◽  
B. Little ◽  
P. Wagner ◽  
M. Meshii

The corrosion of copper and copper alloys in a marine environment is of great concern because of their widespread use in heat exchangers and steam condensers in which natural seawater is the coolant. It has become increasingly evident that microorganisms play an important role in the corrosion of a number of metals and alloys under a variety of environments. For the past 15 years the use of SEM has proven to be useful in studying biofilms and spatial relationships between bacteria and localized corrosion of metals. Little information, however, has been obtained using TEM capitalizing on its higher spacial resolution and the transmission observation of interfaces. The research presented herein is the first step of this new approach in studying the corrosion with biological influence in pure copper.Commercially produced copper (Cu, 99%) foils of approximately 120 μm thick exposed to a copper-tolerant marine bacterium, Oceanospirillum, and an abiotic culture medium were subsampled (1 cm × 1 cm) for this study along with unexposed control samples.


Sign in / Sign up

Export Citation Format

Share Document