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1.
Correlation of anaerobic biodegradability and the electrochemical
characteristic of azo dyes 总被引:3,自引:0,他引:3
Some experiments were conducted to study some electrochemical factors affecting the bacterial reduction (cleavage) of azo dyes, knowledge of which will be useful in the wastewater treatments of azo dyes. A common mixed culture was used as a test organism and the reductions of Acid Yellow 4, 11, 17 and Acid Yellow BIS were studied. It was found that the azo dyes were reduced at different rates, which could be correlated with the reduction potential of the azo compounds in cyclic voltammetric experiments. Acid Yellow BIS (E
r − 616.75 mV) was reduced at the highest rate of 0.0284 mol g dry cell weight−1 h−1, Acid Yellow 11 (E
r − 593.25 mV) at 0.0245 mol g dry cell weight−1 h−1 and Acid Yellow 4 (E
r − 513 mV) at 0.0178 mol g dry cell weight−1 h−1. At the same time, the decolourization rate of Acid Yellow 17 (E
r − 627.5 mV) was 0.0238 mol g dry cell weight−1 h−1, which was affected by the nature of chlorine substituent. Reduction of these azo dyes did not occur under aeration conditions. These studies with a common mixed culture indicate that the reduction of azo dyes may be influenced by the chemical nature of the azo compound. The reduction potential is a preliminary tool to predict the decolourization capacity of oxidative and reductive biocatalysts. 相似文献
2.
Sieved agricultural soil samples were treated with the anti-knock agent tetraethyl lead (Et4Pb), and the resulting effects were analyzed by microcalorimetry. Et4Pb additions resulted in an increase of the heat production rate, provided that oxygen was present and that the soil was not
autoclaved. The increased heat production rate was accompanied by degradation of Et4Pb, as verified by speciation analysis (GC-MS) of the remaining Et4Pb and its ionic degradation products (triethyl lead and diethyl lead cations). Conclusive evidence was obtained that these
transformations were mediated mainly by microbes. At an initial Et4Pb concentration of 2 g Pb/kg dry weight the biodegradation rate was about 780 μmol day−1 kg dry weight−1, whilst the chemical decomposition was only 50 μmol day−1 kg dry weight−1. A fivefold rise of the initial Et4Pb concentration resulted in a decrease of the biodegradation rate to 600 μmol day−1 kg dry weight−1 and an increase of the chemical decomposition to 200 μmol day−1 kg dry weight−1. The biodegradation rate was not influenced by the addition of glucose, which means that no indication for a cometabolic
attack of Et4Pb was found.
Received: 25 February 1997 / Received revision: 22 April 1997 / Accepted: 27 April 1997 相似文献
3.
Fructose and H2 were compared as electron donors for hydrogenation of carbon-carbon double bonds using Acetobacterium woodii. Caffeate was used as a model substrate. An electron donor was required and both fructose and H2 were suitable. With fructose as the donor, the K
s for caffeate was 0.5 mM and the V
max was 678 mmol kgdry weight
−1 h−1.␣Fructose oxidation was coupled very efficiently to caffeate reduction by an alteration in the fructose fermentation so that
acetate was no longer produced.
Received: 24 June 1996 / Accepted: 1 July 1996 相似文献
4.
The use of amiloride to uncouple branchial sodium and proton fluxes in the brown trout, Salmo trutta
I. D. Nelson W. T. W. Potts H. Huddart 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(2):123-128
Resting proton, ammonium and sodium fluxes in Salmo trutta were 492.6 ± 19.5 (n = 29); 122.9 ± 34.2 (n = 28) and 277.1 ± 18.5 (n = 50) μmol · kg−1 · h−1, respectively. The resting transepithelial potential was found to be composed of three successive potentials, the outermost
averaging −7.36 ± 0.19mV, the second, −14.3 ± 1.4 mV and the third −37 ± 1.7 mV. Amiloride inhibits the proton, ammonium and
sodium fluxes in a dose-dependent manner at concentrations of 0.5 mmol · 1−1 and 0.1 mmol · l−1, but at 0.01 mmol · l−1, proton and ammonium fluxes remained at control levels whilst the sodium was reduced to 70.59 ± 7.29 μmol · kg−1 · h−1. The trans-epithelial potential was effected in a bi-phasic manner by 0.5 mmol · l−1 amiloride. An initial hyperpolarisation of ca. 6 mV was followed by a sustained depolarisation of ca. 14 mV (towards zero)
which persisted until the amiloride was washed off the gill. The initial hyperpolarisation was thought to reflect a rapid
inhibition of a positive inward sodium current and the subsequent depolarisation was due to the inhibition of a positive outward
current (proton) which would abolish the transepithelial potential. However, at 0.01 mmol · l−1 only the hyperpolarisation was seen, due to the inhibition of only the inward sodium current. Acetazolamide (0.1 mmol · l−1) was found to have no significant effect on the proton, ammonium and sodium fluxes. These results indicate that the proton
and sodium fluxes across the gill of the freshwater trout are not tightly linked. While this suggests that the trout gill
resembles the model of Ehrenburg et al. (1985) of sodium uptake in frog skin, the apical potentials measured in the pavement
epithelial cell(s) are too low to account for sodium uptake unless the activity of the sodium in the cells is very low.
Accepted: 8 August 1996 相似文献
5.
U. Horn W. Strittmatter A. Krebber U. Knüpfer M. Kujau R. Wenderoth K. Müller S. Matzku A. Plückthun D. Riesenberg 《Applied microbiology and biotechnology》1996,46(5-6):524-532
Functional bivalent miniantibodies, directed against the epidermal growth factor receptor, accumulated to more than 3 gl−1 in high-cell-density cultures of Escherichia coli RV308(pHKK) on a pilot scale. The miniantibodies consist of scFv fragments with a C-termi-nal hinge followed by a helix-turn-helix
motif, which homodimerizes in vivo. The improved expression vector pHKK is characterized by the hok/sok suicide system, improving plasmid maintenance, and the inducible lac p/o promoter system with the very strong T7g10 Shine-Dalgarno sequence. The expression unit is flanked by terminators. The prototrophic
RV308 cells were cultivated in glucose mineral salt medium and reached a cell density of 145 g dry biomass l−1 after 33 h. After induction, growth continued almost unchanged for a further 4 h with concomitant miniantibody formation.
In the fed-batch phase, the concentration of glucose was kept almost constant at the physiological level of approximately
1.5 g l−1, using on-line flow injection analysis for control. Surprisingly, E. coli RV308(pHKK) did not accumulate significant amounts of the metabolic by-product acetate under these unlimited aerobic growth
conditions.
Received: 26 February 1996 / Received revision: 1 August 1996 / Accepted: 12 August 1996 相似文献
6.
Poly-(3-hydroxybutyrate) production from whey by high-density cultivation of recombinant Escherichia coli 总被引:2,自引:0,他引:2
Recombinant Escherichia coli strain GCSC 6576, harboring a high-copy-number plasmid containing the Ralstonia eutropha genes for polyhydroxyalkanoate (PHA) synthesis and the E. coli ftsZ gene, was employed to produce poly-(3-hydroxybutyrate) (PHB) from whey. pH-stat fed-batch fermentation, using whey powder
as the nutrient feed, produced cellular dry weight and PHB concentrations of 109 g l−1 and 50 g l−1 respectively in 47 h. When concentrated whey solution containing 210 g l−1 lactose was used as the nutrient feed, cellular dry weight and PHB concentrations of 87 g l−1 and 69 g l−1 respectively could be obtained in 49 h by pH-stat fed-batch culture. The PHB content was as high as 80% of the cellular dry
weight. These results suggest that cost-effective production of PHB is possible by fed-batch culture of recombinant E. coli using concentrated whey solution as a substrate.
Received: 19 December 1997 / Received revision: 17 March 1998 / Accepted: 20 March 1998 相似文献
7.
P. Becker I. Abu-Reesh S. Markossian G. Antranikian H. Märkl 《Applied microbiology and biotechnology》1997,48(2):184-190
A thermostable lipase was produced in continuous cultivation of a newly isolated thermophilic Bacillus sp. strain IHI-91 growing optimally at 65 °C. Lipase activity decreased with increasing dilution rate while lipase productivity
showed a maximum of 340 U l−1 h−1 at a dilution rate of 0.4 h−1. Lipase productivity was increased by 50% compared to data from batch fermentations. Up to 70% of the total lipase activity
measured was associated to cells and by-products or residual substrate. Kinetic and stoichiometric parameters for the utilisation
of olive oil were determined. The maximal biomass output method led to a saturation constant K
S of 0.88 g/l. Both batch growth data and a washout experiment yielded a maximal specific growth rate, μmax, of 1.0 h−1. Oxygen uptake rates of up to 2.9 g l−1h−1 were calculated and the yield coefficient, Y
X/O, was determined to be 0.29 g dry cell weight/g O2. From an overall material balance the yield coefficient, Y
X/S, was estimated to be 0.60 g dry cell weight/g olive oil.
Received: 8 January 1997 / Received revision: 30 April 1997 / Accepted: 4 May 1997 相似文献
8.
I-Y Lee W T Seo G J Kim M K Kim C S Park Y H Park 《Journal of industrial microbiology & biotechnology》1997,18(4):255-259
Maltose and sucrose were efficient carbon sources for the production of curdlan by a strain of Agrobacterium sp. A two-step, fed-batch operation was designed in which biomass was first produced, followed by curdlan production which
was stimulated by nitrogen limitation. There exists an optimal timing for nitrogen limitation for curdlan production in the
two-step, fed-batch operation. Maximum curdlan production (60 g L−1) was obtained from sucrose with a productivity of 0.2 g L−1 h−1 when nitrogen was limited at a cell concentration of 16.0 g L−1. It was also noted that the curdlan yield from sucrose was as high as 0.45 g curdlan g−1 sucrose, and the highest specific production rate was 1.0 g curdlan g−1 cells h−1 right after nitrogen limitation. Of particular importance was the use of molasses as a cheap carbon source to produce curdlan
in the two-step, fed-batch cultivation. As high as 42 g L−1 of curdlan with a yield of 0.35 g curdlan g−1 total sugar was obtained after 120 h of fed-batch cultivation.
Received 20 August 1996/ Accepted in revised form 26 November 1996 相似文献
9.
Poly(hydroxybutyric acid) (PHB) was produced by a selectant of Azotobacter beijerinckii in media containing only organic nitrogen sources such as N substrates. The chosen compounds were casein peptone, yeast extract,
casamino acids and urea, each combined with carbon substrates glucose or sucrose. The PHB was synthesized under growth-associated
conditions. The concentrations amounted to more than 50% of cell dry mass on casein peptone/glucose as well as urea/glucose
medium within 45 h fermentation time. Corresponding to these yields, productivities of about 0.8 g PHB l−1 h−1 were discovered. The highest values increased to 1.06 g PHB l−1 h−1 on casein peptone/glucose medium and 1.1 g PHB l−1 h−1 on yeast extract/glucose medium after a period of 20 h. It was found that oxygen limitation was essential for successful
product formation, as demonstrated earlier. These data from basic research may support further investigations into the use
of technical proteins from renewable sources as substrates for PHB production by a strain of A. beijerinckii.
Received: 3 June 1997 / Received revision: 29 August 1997 / Accepted: 15 September 1997 相似文献
10.
Nigel J. Adams Berry Pinshow Leonard Z. Gannes 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(6):444-450
We used tritium-labeled water to measure total body water, water influx (which approximated oxidative water production) and
water efflux in free-flying tippler pigeons (Columba livia) during flights that lasted on average 4.2 h. At experimental air temperatures ranging from 18 to 27 °C, mean water efflux
by evaporation and excretion [6.3 ± 1.3 (SD) ml · h−1, n = 14] exceeded water influx from oxidative water and inspired air (1.4 ± 0.7 ml · h−1, n = 14), and the birds dehydrated at 4.9 ± 0.9 ml · h−1. This was not significantly different from gravimetrically measured mass loss of 6.2 ± 2.1 g · h−1 (t = 1.902, n = 14, P>0.05). This flight-induced dehydration resulted in an increase in plasma osmolality of 4.3 ± 3.0 mosmol · kg−1 · h−1 during flights of 3–4 h. At 27 °C, the increase in plasma osmolality above pre-flight levels (ΔP
osm = 7.6±4.29 mosmol · kg−1 · h−1, n = 6) was significantly higher than that at 18 °C (ΔP
osm = 0.83±2.23 mosmol · kg−1 · h−1, (t = 3.43, n = 6, P < 0.05). Post-flight haematocrit values were on average 1.1% lower than pre-flight levels, suggesting plasma expansion. Water
efflux values during free flight were within 9% of those in the one published field study (Gessaman et al. 1991), and within
the range of values for net water loss determined from mass balance during wind tunnel experiments (Biesel and Nachtigall
1987). Our net water loss rates were substantially higher than those estimated by a simulation model (Carmi et al. 1992) suggesting
some re-evaluation of the model assumptions is required.
Accepted: 8 April 1997 相似文献
11.
Mineralization of pentachlorophenol in a contaminated soil by Pseudomonas sp UG30 cells encapsulated in κ-carrageenan 总被引:2,自引:0,他引:2
M B Cassidy H Mullineers H Lee J T Trevors 《Journal of industrial microbiology & biotechnology》1997,18(1):43-48
A fermentation process in Escherichia coli for production of supercoiled plasmid DNA for use as a DNA vaccine was developed using an automated feed-back control nutrient
feeding strategy based on dissolved oxygen (DO) and pH. The process was further automated through a computer-aided data
processing system to regulate the cell growth rate by controlling interactively both the nutrient feed rate and agitation
speed based on DO. The process increased the total yield of the plasmid DNA by approximately 10-fold as compared to a manual
fed-batch culture. The final cell yield from the automated process reached 60 g L−1 of dry cell weight (OD600 = 120) within 24 h. A plasmid DNA yield of 100 mg L−1 (1.7 mg g−1 cell weight) was achieved by using an alkaline cell lysis method. Plasmid yield was confirmed using High Performance Liquid
Chromatography (HPLC) analysis. Because cells had been grown under carbon-limiting conditions in the automated process,
acetic acid production was minimal (below 0.01 g L−1) throughout the fed-batch stage. In contrast, in the manual process, an acid accumulation rate as high as 0.36 g L−1 was observed, presumably due to the high nutrient feed rates used to maintain a maximum growth rate. The manual fed-batch
process produced a low cell density averaging 10–12 g L−1 (OD600 = 25–30) and plasmid yields of 5–8 mg L−1 (approximately 0.7 mg g−1 cells). The improved plasmid DNA yields in the DO- and pH-based feed-back controlled process were assumed to be a result
of a combination of increased cell density, reduced growth rate (μ) from 0.69 h−1 to 0.13 h−1 and the carbon/nitrogen limitation in the fed-batch stage. The DO- and pH-based feed-back control, fed-batch process has
proven itself to be advantageous in regulating cell growth rate to achieve both high cell density and plasmid yield without
having to use pure oxygen. The process was reproducible in triplicate fermentations at both 7-L and 80-L scales.
Received 22 March 1996/ Accepted in revised form 20 September 1996 相似文献
12.
The continuous fermentation of 1,3-propanediol from glycerol by Clostridium butyricum was subjected to cell recycling by filtration using hollow-fibre modules made from polysulphone. The performance of the culture
system was checked at a retention ratio (dilution rate/bleed rate) of 5, dilution rates between 0.2 h−1 and 1.0 h−1 and glycerol input concentrations of 32 g l−1 and 56 g l−1. The near-to-optimum propanediol concentration of 26.5 g l−1 (for 56 g l−1 glycerol) was maintained up to a dilution rate of 0.5 h−1 and then decreased while the propanediol productivity was highest at 0.7 h−1. The productivity could be increased by a factor of four in comparison to the continuous culture without cell recycling.
By application of the model of Zeng and Deckwer [(1995) Biotechnol Prog 11: 71–79] for cultures under substrate excess, it
was shown that the limitations resulted exclusively from product inhibition and detrimental influences from the cell recycling
system, such as shear stress, were not involved.
Received: 20 October 1997 / Received revision: 12 December 1997 / Accepted: 14 December 1997 相似文献
13.
Q. Hu N. Kurano M. Kawachi I. Iwasaki S. Miyachi 《Applied microbiology and biotechnology》1998,49(6):655-662
To test the feasibility of CO2 remediation by microalgal photosynthesis, a modified type of flat-plate photobioreactor [Hu et al. (1996) Biotechnol Bioeng 51:51–60] has been designed for cultivation of a high-CO2-tolerant unicellular green alga Chlorococcum littorale. The modified reactor has a narrow light path in which intensive turbulent flow is provided by streaming compressed air through
perforated tubing into the culture suspension. The length of the reactor light path was optimized for the productivity of
biomass. The interrelationship between cell density and productivity, as affected by incident light intensity, was quantitatively
assessed. Cellular ultrastructural and biochemical changes in response to ultrahigh cell density were investigated. The potential
of biomass production under extremely high CO2 concentrations was also evaluated. By growing C. littorale cells in this reactor, a CO2 fixation rate of 16.7 g CO2 l−1 24 h−1 (or 200.4 g CO2 m−2 24 h−1) could readily be sustained at a light intensity of 2000 μmol m−2 s−1 at 25 °C, and an ultrahigh cell density of well over 80 g l−1 could be maintained by daily replacing the culture medium.
Received: 20 October 1997 / Received revision: 19 December 1997 / Accepted: 24 January 1998 相似文献
14.
Light response characteristics of a morphologically diverse group of southern hemisphere conifers as measured by chlorophyll fluorescence 总被引:5,自引:0,他引:5
Unlike northern hemisphere conifer families, the southern family, Podocarpaceae, produces a great variety of foliage forms
ranging from functionally broad-, to needle-leaved. The production of broad photosynthetic surfaces in podocarps has been
linked qualitatively to low-light-environments, and we undertook to assess the validity of this assumption by measuring the
light response of a morphologically diverse group of podocarps. The light response, as apparent photochemical electron transport
rate (ETR), was measured by modulated fluorescence in ten species of this family and six associated species (including five
Cupressaceae and one functionally needle-leaved angiosperm) all grown under identical glasshouse conditions. In all species,
ETR was found to increase as light intensity increased, reaching a peak value (ETRmax) at saturating quantum flux (PPFDsat), and decreasing thereafter. ETRmax ranged from 217 μmol electrons · m−2 · s−1 at a PPFDsat of 1725 μmol photons · m−2 · s−1 in Actinostrobus acuminatus to an ETR of 60 μmol electrons · m−2 · s−1 at a PPFDsat of 745 μmol electrons · m−2 · s−1 in Podocarpus dispermis. Good correlations were observed between ETRmax and both PPFDsat and maximum assimilation rate measured by gas-exchange analysis. The effective quantum yield at light saturation remained
constant in all species with an average value of 0.278 ± 0.0035 determined for all 16 species. Differences in the shapes of
light response curves were related to differences in the response of non-photochemical quenching (q
n), with q
n saturating faster in species with low PPFDsat. Amongst the species of Podocarpaceae, the log of average shoot width was well correlated with PPFDsat, wider leaves saturating at lower light intensities. This suggests that broadly flattened shoots in the Podocarpaceae are
an adaptation to low light intensity.
Received: 15 April 1996 / Accepted: 30 September 1996 相似文献
15.
A. M. Fauzi David J. Hardman Alan T. Bull 《Applied microbiology and biotechnology》1996,46(5-6):660-666
The degradation of low concentrations of 1,3-dichloro-2-propanol (1,3-DCP) and related halohydrins by whole cells and cell-free
extracts of soil bacteria has been investigated. Three bacteria (strains A1, A2, A4), isolated from the same soil sample,
were distinguished on the basis of cell morphology, growth kinetics and haloalcohol dehalogenase profiles. Strain A1, probably
an Agrobacterium sp., dehalogenated 1,3-DCP with the highest specific activity (0.33 U mg protein−1) and also had the highest affinity for 1,3-DCP (K
m, 0.1 mM). Non-growing cells of this bacterium dehalogenated low concentrations of 1,3-DCP with a first-order rate constant
(k
1) of 1.13 h−1 . The presence of a non-dehalogenating bacterium, strain G1 (tentatively identified as Pseudomonas mesophilius), did not enhance the dehalogenation rate of low 1,3-DCP concentrations. However, the mixed-species consortium of strains
A1 and G1 had greater stability than the mono-species culture at DCP concentrations above 1.0 gl−1.
Received: 30 April 1996 / Received revision: 30 July 1996 / Accepted: 5 August 1996 相似文献
16.
Plant cell suspension culture in a bench-scale fermenter with a newly designed membrane stirrer for bubble-free aeration 总被引:1,自引:0,他引:1
C. Böhme M.-B. Schröder H. Jung-Heiliger J. Lehmann 《Applied microbiology and biotechnology》1997,48(2):149-154
In this paper, tests of an optimized membrane-stirrer geometry for bubble-free aeration of a plant cell suspension culture
are described. Cell attachment and clogging of a previously described system [Piehl et al. (1988) Appl Microbiol Biotechnol
29:456–461] led to the development of a new stirrer. The volumetric oxygen transfer capacity has been measured in aqueous
medium. The mass transfer coefficient, k
l
a, was 3.75 h−1 at 25 °C and at a stirrer speed of 34 rpm. The overall oxygen transfer capacity was investigated with a suspension culture
of Aesculus hippocastanum. It was shown that the oxygen mass transfer was sufficient even at the maximum biomass of 10–12 g dry weight/l, which was
obtained by using this system. Furthermore, special attention was given to medium components like C and N sources, to avoid
growth limitation due to a shortage of nutrients.
Received: 22 October 1996 / Revised version: 11 March 1997 / Accepted: 14 March 1997 相似文献
17.
H. De Wever S. De Cort I. Noots H. Verachtert 《Applied microbiology and biotechnology》1997,47(4):458-461
2-Hydroxybenzothiazole (OBT) is present in wastewaters from the industrial production of the rubber vulcanization accelerator
2-mercaptobenzothiazole (MBT). We have achieved the first isolation of axenic bacterial cultures capable of the degradation
of OBT and growth on this substrate as the sole source of carbon, nitrogen and energy. All isolates had similar characteristics
corresponding to one particular isolate, which was studied in more detail and identified as Rhodococcus rhodochrous. The strains were also capable of degrading benzothiazole (BT) but not MBT or benzothiazole-2-sulphonate (BTSO3). OBT was degraded at a concentration of up to 600 mg · l−1. BT was toxic above 300 mg · l−1. MBT inhibited OBT degradation. Growth on OBT was not significantly different at pH values of between 6.3 and 7.9 or salt
concentrations between 1 % and 3 %. In shake flasks the cells clumped together, which resulted in a lower rate of oxygen transfer
and slower degradation as compared to cells grown on OBT in a stirred reactor.
Received: 22 August 1996 / Received revision: 29 November 1996 / Accepted: 29 November 1996 相似文献
18.
A Pessoa Jr I M de Mancilha S Sato 《Journal of industrial microbiology & biotechnology》1997,18(6):360-363
Sugar cane bagasse hemicellulosic fraction submitted to hydrolytic treatment with 100 mg of sulfuric acid per gram of dry
mass, at 140°C for 20 min, was employed as a substrate for microbial protein production. Among the 22 species of microorganisms
evaluated, Candida tropicalis IZ 1824 showed TRS consumption rate of 89.8%, net cell mass of 11.8 g L−1 and yield coefficient (Yx/s) of 0.50 g g−1. The hydrolyzate supplemented with rice bran (20.0 g L−1), P2O5 (2.0 g L−1) and urea (2.0 g L−1) provided a TRS consumption rate of 86.3% and a cell mass of 8.4 g L−1. At pH 4.0 cellular metabolism was inhibited, whereas at pH 6.0 the highest yield was obtained. The presence of furfural
(2.0 g L−1) hydroxymethylfurfural (0.08 g L−1) and acetic acid (3.7 g L−1) in the hydrolyzate did not interfere with cultivation at pH 6.0.
Received 25 October 1996/ Accepted in revised form 10 March 1997 相似文献
19.
Juan Fuentes F. B. Eddy 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(6):438-443
Drinking in Atlantic salmon (Salmo salar) juveniles was investigated in fresh water and following transfer to sea water. There was a significant effect of fish size
on drinking, and smolts (20–30 g) imbibed about ten times less water than alevins of 0.2–0.3 g. Freshwater smolts drank at
a rate of 0.15 ± 0.03 ml · kg−1 · h−1 and administration of doses of 10 or 20 mg · kg−1 of papaverine (stimulator of the renin- angiotensin system RAS) or [Asn1, Val5]-Angiotensin II (0.4 μmol · kg−1) resulted in significant increases in drinking, while administration of the angiotensin converting enzyme inhibitor, enalapril
(50 mg · kg−1) had no effect on drinking. Transfer of Atlantic salmon smolts to 1/3, 2/3 and full strength sea water resulted in significant
increases in drinking to 1.06 ± 0.12, 1.24 ± 0.0.16 and 3.89 ± 0.28 ml · kg−1 · h−1, respectively. In sea water, stimulation of the endogenous RAS by administration of papaverine (20 mg · kg−1) resulted in a 20% increase in drinking, while administration of enalapril to doses of 50 and 200 mg · kg−1 lowered drinking to 1.99 ± 0.48 and 0.32 ± 0.06 ml · kg−1 · h−1, respectively. All treatments were without effect on blood plasma levels of Na+ and Cl− in fresh water, while in sea water smolts both stimulation and inhibition of drinking resulted in hemoconcentration of Na+ and Cl−. The role of the renin angiotensin system in control of drinking and hydromineral balance in Atlantic salmon is discussed.
Accepted: 27 February 1997 相似文献
20.
H. Sudo A. Yamada K. Kokatsu N. Nakamura T. Matsunaga 《Applied microbiology and biotechnology》1997,47(1):78-82
The marine photosynthetic bacterium Chromatium sp. successfully removed orthophosphate when grown phototrophically. The phosphate-uptake rate was almost constant at more
than 5.0 mg- PO4
3−/l in synthetic medium. Addition of seawater causes flocculation of this strain. The successful use of seawater as an inexpensive
source of magnesium could prove to be effective in the removal of photosynthetic bacterial cells from a medium. A semicontinuous
culture system was used for the removal of low concentrations of phosphate and the phosphate-uptake activity of Chromatium sp. was maintained under 0.1 day−1 dilution rate. This strain was also able to remove high concentrations of phosphate from domestic sewage.
Received 24 May 1996 / Received revision: 5 August 1996 / Accepted: 6 September 1996 相似文献