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1.
Rachael E. Van Pelt Wendolyn S. Gozansky Wendy M. Kohrt 《Obesity (Silver Spring, Md.)》2013,21(1):E162-E165
Objective:
Assessment of antilipolytic insulin action is important in obesity research, but extensive isotopic tracer studies are not always feasible. We evaluated whether an index of antilipolytic insulin action could be derived from readily available insulin and glycerol concentrations obtained during clamps or oral glucose tolerance tests (OGTT).Design and Methods:
We evaluated data collected from 29 subjects who had undergone a 3‐stage hyperinsulinemic‐euglycemic clamp (4, 8, and 40 mU/m2/min) with infusion of [2H5]glycerol to calculate the glycerol rate of appearance (GLYRA). Exponential decay curves for GLYRA across insulin concentrations were generated for each individual and suppression of lipolysis was calculated as the insulin concentration needed to half‐maximally suppress GLYRA (GLYRA EC50). Areas under the curve for glycerol (GLYAUC) and insulin (INSAUC) were calculated and their products (INSAUC × GLYAUC) were calculated as an index of insulin suppression of lipolysis.Results:
The clamp index was highly correlated with GLYRA EC50 (r = 0.862, P < 0.001), as was an OGTT‐derived index (r = 0.720, P < 0.01).Conclusions:
These findings suggest that the products of the insulin and glycerol AUC from either a clamp or an OGTT are good biomarkers of the antilipolytic action of insulin and are comparable with direct measurement by isotopic tracer methods. 相似文献2.
Seed maturation of Pisum sativum cv. Progress No. 9 proceeds more slowly in winter than in summer even when the parent plants are grown in greenhouse conditions with light-and heat-supplementation. For parent plants grown under summer and winter conditions the metabolism of [3H]GA9 in cultured seeds is qualitatively different in seeds of equivalent age and qualitatively the same in seeds of equivalent weight. 13-Hydroxylation of [3H]GA9[3H]GA20 is restricted to early stages of seed development. 2-Hydroxylation of [3H]GA92-OH-[3H]GA9 has only been observed at a stage of development after endogenous GA9 has accumulated. 2-OH-GA9 has been shown to be endogenous to pea and is named GA51. H2-GA31 and its conjugate have not been shown to be present in pea and may be induced metabolites of [3H]GA9. The metabolism of GA20GA29 is used to illustrate a technique of feeding [2H][3H]GAs in order to distinguish a metabolite from the same endogenous compound. The in vitro conversion of [3H]GA20[3H]GA29, and the virtual non-metabolism of [3H]GA29 have been confirmed for seeds in intact fruits. These results are discussed in relation to the apparent absence of conjugated GAs in mature pea seeds.Abbreviations GAn
gibberellin An
- GC
gas chromatography
- GC-MS
combined gas chromatography-mass spectrometry
- GC-RC
combined gas chromatography-radio counting
- Me
methyl ester
- RT
etention time
- SICM
selected ion current monitoring
- TLC
thin layer chromatography
- TMS
trimethyl silyl ether
The author is née Frydman 相似文献
3.
Taojun He Fang Zhang Jin Zhang Shanshan Wei Jie Ning Hanmei Yuan Bin Li 《Helicobacter》2023,28(3):e12959
Background and aims
Although Helicobacter pylori is recognized as an extracellular infection bacterium, it can lead to an increase in the number of CD8+ T cells after infection. At present, the characteristics of H. pylori antigen-specific CD8+ T cells and the epitope response have not been elucidated. This study was focused on putative protective antigen UreB to detect specific CD8+ T-cell responses in vitro and screen for predominant response epitopes.Methods
The PBMCs collected from H. pylori-infected individuals were stimulated by UreB peptide pools in vitro to identify the immunodominant CD8+ T-cell epitopes. Furthermore, their HLA restriction characteristics were detected accordingly by NGS. Finally, the relationship between immunodominant responses and appearance of gastric symptoms after H. pylori infection was conducted.Results
UreB-specific CD8+ T-cell responses were detected in H. pylori-infected individuals. Three of UreB dominant epitopes (A-2 (UreB443–451: GVKPNMIIK), B-4 (UreB420–428: SEYVGSVEV), and C-1 (UreB5–13: SRKEYVSMY)) were firstly identified and mainly presented by HLA-A*1101, HLA-B*4001 and HLA-C*0702 alleles, respectively. C-1 responses were mostly occurred in H. pylori-infected subjects without gastric symptoms and may alleviate the degree of gastric inflammation.Conclusions
The UreB dominant epitope-specific CD8+ T-cell response was closely related to the gastric symptoms after H. pylori infection, and the C-1 (UreB5-13) dominant peptides may be protective epitopes. 相似文献4.
R. Huch J. D'Haese Ch. Gerday 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1988,158(3):325-334
Summary Soluble calcium-binding proteins (SCBP) considerably different from calmodulin were purified from the body wall muscle of the earthwormLumbricus terrestris. Three isoforms were obtained with similar UV absorption spectra and amino acid compositions and an apparent molecular weight close to 20 kDa. They can be distinguished by their histidine and proline content and by their peptide maps. The tissue content, as determined by quantitative ELISA varies individually from 0.1 to 0.3 mmol kg–1. The calcium-binding property can be demonstrated by Ca2+-dependent electrophoretic mobility shift and45Ca2+ autoradiography on nitrocellulose sheets. The apparentK
D values for the SCBP-Ca2+ complex is approximately 10–7 mol l–1 as revealed by euquilibrium and flow dialysis experiments. In the presence of 1 mmol l–1 MgCl2 the maximum binding capacity of SCBP was determined to be either 2 mol Ca2+ mol–1 protein (SCBP2) or 3 mol Ca2+ mol–1 protein (SCBP3). Preliminary studies concerning the functional role of SCBP indicate that it facilitates the diffusion of Ca2+ ions by a factor of 2 and is capable of inhibiting the ATPase of isolated body wall muscle actomyosin. The results reveal that earthworm SCBP are similar to vertebrate parvalbumin and to SCBP characterized from aquatic invertebrates.Abbreviations
ABTS
2,2-azino-di-(3-ethyl)-benzothiazolinsulfonate
-
CN-PDE
3:5-cyclic nucleotide-phosphodiesterase
-
DEAE
diethylaminoethyl
-
EGTA
ethyleneglycol-bis(-aminoethyl ether)-N,N,N,N-tetraacetic acid
-
ELISA
enzyme linked immuno sorbent assay
-
HEPES
N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid
-
HPLC
high performance liquid chromatography
-
HRP
horseradish peroxydase
-
PAGE
polyacrylamide gel electrophoresis
-
PBS
phosphate buffered saline
-
P
i
inorganic phosphate
-
PMSF
phenylmethylsulfonyl fluoride
-
SCBP
soluble calcium-binding protein
-
SDS
sodium dodecyl sulphate
-
SPDP
N-succininydyl-3-(2-pyridyldithio)propionate
-
SR
sarcoplasmic reticulum
-
Tris
tris(hydroxymethyl)-aminomethane
-
UV
ultraviolet 相似文献
5.
Shiying Li Roland Maude‐Griffin Andrew J. Pullan Jiande D Z Chen 《Obesity (Silver Spring, Md.)》2013,21(2):326-335
Objective:
Accelerated gastric emptying that precipitates hunger and frequent eating could be a potential factor in the development of obesity. The aim of this study was to study gastric emptying in diet‐induced obese‐prone (DIO‐P) and DIO‐resistant (DIO‐R) rats and explore possible differences in electrical properties of calcium (Ca2+) and potassium (K+) channels of antral circular smooth muscle cells (SMCs).Design and Methods:
Whole‐cell patch‐clamp technique was used to measure Ca2+ and K+ currents in single SMCs. Gastric emptying was evaluated 90 min after the ingestion of a solid meal.Results:
Solid gastric emptying in the DIO‐P rats was significantly faster compared with that in the DIO‐R rats. The peak amplitude of L‐type Ca2+ current (IBa,L) at 10 mV in DIO‐P rats was greater than that in DIO‐R rats without alternation of the current–voltage curve and voltage‐dependent activation and inactivation. The half‐maximal inactivation voltage of transient outward K+ current (IKto) was more depolarized (~4 mV) in DIO‐P rats compared with that in DIO‐R rats. No difference was found in the current density or recovery kinetics of IKto between two groups. The current density of delayed rectifier K+ current (IKdr), which was sensitive to tetraethylammonium chloride but not 4‐aminopyridine, was lower in DIO‐P rats than that in DIO‐R rats.Conclusion:
The accelerated gastric emptying in DIO‐P rats might be attributed to a higher density of IBa,L, depolarizing shift of inactivation curve of IKto and lower density of IKdr observed in the antral SMCs of DIO‐P rats. 相似文献6.
K. S. M. S. Raghava Rao M. K. Gowthaman N. P. Ghildyal Dr. N. G. Karanth 《Bioprocess and biosystems engineering》1993,8(5-6):255-262
A simple mathematical model for the interaction of mass transport with biochemical reaction in solid state fermentations (SSF) in static tray type bioreactors under isothermal conditions has been developed. The analysis has enabled scientific explanations to a number of practical observations, through the concept of critical substrate bed thickness. The model will be most useful in the prediction of the concentration gradients as also in efficient design of these bioreactors.List of Symbols
C g/cm3
Oxygen concentration in the bed
-
C
g g/cm3
Atmospheric oxygen concentration
-
C
*
Dimensionless oxygen concentration, C/C
g
-
D
e cm2/h
Effective diffusivity
-
H cm
Bed thickness or height
-
H
c cm
Critical bed thickness or height
-
H
m cm
Maximum height of zone of zero oxygen concentration
-
p
i mg/(g · h)
Productivity (Eq. 13)
-
R g/(cm3 · h)
Biochemical reaction rate
-
t h
Fermentation time
-
t
*
Dimensionless time, D
e t/H2
-
X mg/cm3
Biomass concentration
-
X
max mg/cm3
Maximum biomass concentration
-
y
Dimensionless thickness or height, (y = z/H)
-
y cm
Thickness of zone of zero oxygen concentration (Eq. 12)
-
Y
Yield coefficient
-
z cm
Bed thickness or height along tray axis
-
Bed void fraction
- max h–1
Specific growth rate
-
Thiele modulus
相似文献
7.
F. X. Malcata 《Bioprocess and biosystems engineering》1994,11(1):23-28
The balance equations pertaining to the modelling of batch reactors performing an enzyme-catalyzed reaction in the presence of enzyme deactivation are developed. The functional form of the solution for the general situation where both the rate of the enzyme-catalyzed reaction and the rate of enzyme deactivation are dependent on the substrate concentration is obtained, as well as the condition that applies if a maximum conversion of substrate is sought. Finally, two examples of practical interest are explored to emphasize the usefulness of the analysis presented.List of Symbols
C
E mol/m3
concentration of active enzyme
-
C
E,O mol/m3
initial concentration of active enzyme
-
C
S mol/m3
concentration of substrate
-
C
S,O mol/m3
initial concentration of substrate
-
C
S,min mol/m3
minimum value for the concentration of substrate
-
k 1/s
first order rate constant associated with conversion of enzyme/substrate complex into product
-
k
1 1/s
first order deactivation constant of enzyme (or free enzyme)
-
k
2 1/s
first order deactivation constant of enzyme in enzyme/substrate complex form
-
K
m mol/m3
Michaelis-Menten constant
-
p mol/(m3s)
time derivative of C
S
-
q mol/m3
auxiliary variable
-
t s
time elapsed after reactor startup
Greek Symbols
1/s
univariate function expressing the dependence of the rate of enzyme deactivation on C
S
-
mol/m3
dummy variable of integration
-
mol/m3
dummy variable of integration
-
1/s
univariate function expressing the dependence of the rate of substrate depletion on C
S
-
m3/(mol s)
derivative of with respect to C
S 相似文献
8.
Summary A special temperature control system has been developed and applied to continuous measuring of the heat evolved during a fermentation process. In this system, the fermentation broth was overcooled by a given constant cooling water flow. The excess heat removed from the fermentor was then made up by an immersion electrical heater. The action of the temperature controller was precisely monitored as it varied in response to the amount of heat produced by the microbial activities.The technique was used for determining the heat evolution byEscherichia coli grown on glucose. The ratio between quantities of total heat release and total oxygen consumption has been determined to be 0.556 MJ/mol O2.The newly developed technique can be employed as an online sensor to monitor the microbial activities of either aerobic or anaerobic fermentation systems.Symbols Cc
Heat capacity of cooling water (MJ/kg · °C)
- Cp
Heat capacity (MJ/kg · °C)
- I
Current of immersion heater (A)
- K
Constant in Equation (2) (h)
- K
Constant in Equation (13) (m3 · h · °C/MJ)
- Qc
Flow rate of cooling water (m3/h)
-
Heat of agitation (MJ/m3 · h)
-
Heat dissipated by the bubbling gas (MJ/m3 · h)
-
Heat removal by the action of controller (MJ/m3 · h)
-
Heat of fermentation (MJ/m3 · h)
-
Heat loss to the surroundings (MJ/m3 · h)
- Qpass
Constant average power dissipated by the immersion heater (MJ/m3 · h)
-
Fluctuating power dissipated by the immersion heater (MJ/m3 · h)
-
Power dissipated by the immersion heater (MJ/m3 · h)
- T
Temperature of fermentation broth (°C)
-
Constant average temperature of fermentation broth (°C)
-
Fluctuating temperature of fermentation broth (°C)
- Ta
Temperature of the ambient air (°C)
- Tc
Inlet temperature of cooling water (°C)
- U1A1
Specific heat transfer coefficient for determination of heat loss to the surroundings (MJ/m3 · h · °C)
- U2A2
Specific heat transfer coefficient for cooling surfaces (MJ/m3 · h · °C)
- U3A3
Constant in Equation (16) (MJ/m3 · h · °C)
- V
Voltage of immersion heater (V)
- VL
Liquid volume (m3)
- OUR
Oxygen uptake rate (mol O2/m3 · h)
Greek Letters Hfo
The ratio between the total heat release and the total oxygen uptake (MJ/mol O2)
- c
Density of cooling water (kg/m3)
-
Time constant defined in Equation (6) (h)
- iMiCpi
Heat capacity of system components (fermentation broth + fermentor jar + stainless steel) (MJ/m3 · °C) 相似文献
9.
Nana‐Maria Wagner Gunnar Brandhorst Frauke Czepluch Mareike Lankeit Christoph Eberle Sebastian Herzberg Vivien Faustin Joachim Riggert Michael Oellerich Gerd Hasenfuss Stavros Konstantinides Katrin Schäfer 《Obesity (Silver Spring, Md.)》2013,21(3):461-468
Objective:
Reduced numbers of regulatory T (Treg) cells have been observed in visceral adipose tissue of obese mice and humans. However, it is unknown whether human obesity affects circulating Treg cells and whether their number is associated with markers of systemic inflammation or glucose intolerance.Design and Methods:
Peripheral blood mononuclear cells were isolated from venous blood of obese (BMI ≥ 27 kg/m2; n = 30) and nonobese (BMI ≥ 27 kg/m2; n = 13) individuals and analyzed using flow cytometry for the expression of CD4, CD25, and Foxp3.Results:
Reduced circulating Treg‐cell numbers were detected in obese compared with nonobese study participants (P = 0.038). Circulating CD4+CD25+CD127?Foxp3 Treg cells inversely correlated with body weight (P = 0.009), BMI (P = 0.004) and plasma leptin levels (P = 0.004) and were reduced in subjects with hsCRP ≥ 3.0 mg/L (P = 0.034) or HbA1c ≥ 5.5% (P < 0.005). Receiver operating characteristic curve analysis revealed a cutoff of circulating Treg cells < 1.06% to be predictive for hsCRP levels ≥ 3.0 mg/L, and logistic regression showed that the risk of having hsCRP levels ≥ 3.0 mg/L was increased 9.6‐fold (P = 0.008), if Treg cells were below this threshold. The Treg cutoff for HbA1c levels ≥ 5.5% was 0.73%, and this cutoff also predicted an increased risk of having elevated levels of both hsCRP and HbA1c, if only obese subjects were examined.Conclusion:
Our findings thus reveal an association between circulating Treg cells and measures of adiposity, inflammation, and glucose intolerance. Although further prospective studies are needed, we present data suggesting that the determination of Treg cells might be useful to identify obese subjects at increased risk of developing cardiovascular and/or metabolic complications.10.
The effectiveness of using micro-gel bead-immobilized cells for aerobic processes was investigated. Glutamine production by Corynebacterium glutamicum, 9703-T, cells was used as an example. The cells were immobilized in Sr-alginate micro-gel beads 500 m in diameter and used for fermentation processes in a stirred tank reactor with a modified impeller at 400 min–1. Continuous production of glutamine was carried out for more than 220 h in this reactor and no gel breakage was observed. As a result of the high oxygen transfer capacity of this system, the glutamine yield from glucose was more than three times higher, while the organic acid accumulation was more than 24 times lower than those obtained with 3.0 mm-gel bead-immobilized cells in an airlift fermentor under similar experimental conditions. During the continuous fermentations there was evolution and proliferation of non-glutamine producing strains which led to a gradual decrease in the productivity of the systems. Although a modified production medium which suppresses cell growth during the production phase was effective in maintaining the productivity, the stability of the whole system was shortened due to high cell deactivation rate in such a medium.List of Symbols
C kg/m3
glutamine concentration
-
C
A
mol/m
3
local oxygen concentration inside the gel beads
-
C
AS
mol/m
3
oxygen concentration at the surface of the gel beads
-
De m2/h
effective diffusion coefficient of oxygen in the gel bead
-
DO mol/m3
dissolved oxygen concentration
-
F dm3/h
medium flow rate
-
K h–1
glutamine decomposition rate constant
-
Km mol/m3
Michaelis Menten constant
-
QO
2max
mol/(kg · h)
maximum specific respiration rate
-
R m
radius of the gel beads
-
r m
radial distance
-
t h
time
-
V
C
dm
3
volume of the gel beads
-
V
L
dm
3
liquid volume in the reactor
-
Vm mol/(m3 · h)
maximum respiration rate
-
X kg/m3
cell concentration
-
x
r/R
-
y
C
A
/CAS
- h–1
cell deactivation rate constant
-
Thiele modulus defined by R(Vm/De Km)
1/2
-
C
AS
/Km
-
C
kg/(m3-gel · h)
specific glutamine formation rate
-
c
dm3-gel/dm3
V
C
/V
L
相似文献
11.
An investigation was performed into the operation of an integrated system for continuous production and product recovery of solvents (acetone-butanol-ethanol) from the ABE fermentation process. Cells of Clostridium acetobutylicum were immobilized by adsorption onto bonechar, and used in a fluidized bed reactor for continuous solvent production from whey permeate. The reactor effluent was stripped of the solvents using nitrogen gas, and was recycled to the reactor. This relieved product inhibition and allowed further sugar utilization. At a dilution rate of 1.37 h–1 a reactor productivity of 5.1 kg/(m3 · h) was achieved. The solvents in the stripping gas were condensed to give a solution of 53.7 kg/m3. This system has the advantages of relieving product inhibition, and providing a more concentrated solution for recovery by distillation. Residual sugar and non-volatile reaction intermediates are not removed by gas stripping and this contributes to high solvent yields.List of Symbols
C kg/m3
Lactose concentration in reactor effluent
-
C
b kg/m3
Lactose concentration in bleed stream
-
C
c kg/m3
Lactose concentration in whey permeate feed
-
C
i kg/m3
Lactose concentration at reactor inlet
-
C
p kg/m3
Lactose concentration in condensed solvent stream (=0)
-
C
r kg/m3
Lactose concentration in recycle line (C
b=C
r)
-
C kg/h
Amount of lactose utilized during certain time period
-
D h1
Dilution rate of reactor, F
i/D=F/D
-
F dm3/h, m3/h
F
i = Rate of feed flow to the reactor
-
F
b
dm
3/h, m3/h
Rate of bleed
-
F
c dm3/h, m3/h
Rate of feed of whey permeate solution
-
F
p dm3/h, m3/h
Rate of concentrated product removal
-
F
r dm3/h, m3/h
Rate of recycle of stripped effluent to the reactor
-
P
l %
Percent lactose utilization
-
R
l kg/(m3 · h)
Overall lactose utilization rate
-
R
p kg/(m3 · h)
Overall reactor (solvent) productivity
-
R
sl kg/h
Rate of solvent loss
- S kg/m3
Solvent concentration in reactor effluent
-
S
b kg/m3
Solvent concentration in bleed
-
S
c kg/m3
0; Solvent concentration in concentrated whey permeate solution
-
S
i kg/m3
Solvent concentration at inlet of reactor
-
S
p kg/m3
Solvent concentration in concentrated product stream
-
S
r kg/m3
Solvent concentration in stripped effluent, S
r=Sb
- S kg/h
Amount of solvent produced from C amount of lactose in a particular time
- ds/dt kg/(m3 · h)
Rate of accumulation of solvents in the stripper
-
t h
Time
-
V dm3, m3
Total reactor volume
-
V
1 dm3, m3
Liquid volume in stripper
-
Y
P/S
Solvent yield 相似文献
12.
Molecular diffusion of solutes, like sucrose in the xanthan gum fermentation, is important in order to understand the complex behavior of mass transfer mechanisms during the process. This work was focused to determine the diffusion coefficient of sucrose, a carbon source for xanthan production, using similar sucrose and xanthan concentrations to those occurring in a typical fermentation. The diaphragm cell method was used in experimental determinations. The data showed that diffusion coefficient of sucrose significantly decreases when xanthan gum concentration increases. Theoretical and semiempirical models were used to predict sucrose diffusivity in xanthan solutions. Molecular properties and rheological behavior of the system were considered in the modeling. The models tested fitted well the behavior of experimental data and that reported for oxygen in the same system.List of Symbols
A
constant in eq. (5)
-
C
pg cm–3
polymer concentration
-
D cm2 s–1
diffusivity
-
D
ABcm2 s–1
diffusivity of A through liquid solvent
-
D
APcm2 s–1
diffusivity of A in polymer solution
-
D
AWcm2 s–1
diffusivity of A in water
-
D
Pcm2 s–1
diffusivity of polymer in liquid solvent
-
E
D
gradient of the activation energy for diffusion
-
H
P
hydratation factor of the polymer in water (g of bound water/g of polymer)
-
K dyn sn cm–2
consistency index
-
K
1
constant in eq. (5)
-
K
P
overall binding coefficient [g of bound solute/cm3 of solution]/[g of free solute/cm3 of polymer free solution]
-
n
flow behavior index
-
M
Bg g mol–1
molucular weight of liquid solvent
-
M
Pg g mol–1
molecular weight of the polymer
-
M
Sg g mol–1
Molecular weight of polymer solution (= M
BXB+MPXP)
-
R cm3 atm g mol–1 K–1
ideal gas law constant
-
T K
absolute temperature
-
V
Bcm3 g mol–1
molar volume of liquid solvent
-
V
Pcm3 g mol–1
molar volume of polymer
-
V
Scm3 g mol–1
molar volume of polymer solution
-
X
B
solvent molar fraction
-
X
P
polymer molar fraction
-
polymer blockage shape factor
-
P
volume fraction of polymer in polymer solution
-
g cm–1 s–1
viscosity
-
ag cm–1 s–1
apparent viscosity of the polymer solution
-
icm3 g–1
intrinsic viscosity
-
0 g cm–1 s–1
solvent viscosity
-
Pg cm–1 s–1
polymer solution viscosity
-
R
relative viscosity (= /
0)
-
=0 g cm–1 s–1
viscosity of polymer solution obtained at zero shear rate
-
0 g cm–3
water density 相似文献
13.
T. Hagi M. Kobayashi S. Kawamoto J. Shima M. Nomura 《Journal of applied microbiology》2013,114(6):1763-1771
Aims
To determine whether the carotenoid production improves stress tolerance of lactic acid bacteria, the cloned enterococcal carotenoid biosynthesis genes were expressed in Lactococcus lactis ssp. cremoris MG1363, and the survival rate of carotenoid‐producing engineered MG1363 strain under stress condition was investigated.Methods and Results
We cloned carotenoid biosynthesis genes from yellow‐pigmented Enterococcus gilvus. The cloned genes consisted of crtN and crtM and its promoter region were inserted into the shuttle vector pRH100, and the resulting plasmid was named pRC. The cloned crtNM was expressed using pRC in noncarotenoid‐producing L. lactis ssp. cremoris MG1363. The expression of crtNM led to the production of C30 carotenoid 4,4′‐diaponeurosporene. After exposure to 32 mmol l?1 H2O2, low pH (1.5, acidified with HCl), 20% bile acid and 12 mg ml?1 lysozyme, the survival rates of the MG1363 strain harbouring pRC were 18.7‐, 6.8‐, 8.8‐ and 4.4‐fold higher, respectively, than those of MG1363 strain harbouring the empty vector pRH100.Conclusions
The expression of carotenoid biosynthesis genes from Ent. gilvus improves the multistress tolerance of L. lactis.Significance and Impact of the study
First report of the improvement of multistress tolerance of lactic acid bacteria by the introduction of genes for carotenoid production. 相似文献14.
Prof. Dr. A. Urbanek S. Razmadhan M. Jaworska 《Bioprocess and biosystems engineering》1989,4(2):91-94
A procedure is described for measuring the rate of biooxidation of elemental sulphur in nutrient solutions. Results of preliminary measurements of sulphur bio-oxidation rate in a dynamic system are presented. The rate of sulphur bio-oxidation has been determined at the level of 0.02–0.05 g of sulphur per m2 of sulphur per h.List of Symbols
C g/dm3
concentration of sulphate ions
-
C
2 g/dm3
concentration of sulphate ions in withdrawn solution
-
C g/dm3
C difference between solution outlet and inlet to sulphur bed
-
F m2
sulphur surface exposed to bacteria action
-
m g
mass of elemental sulphur
-
V dm3
volume of solution
-
V
0 dm3/h
volume of fresh solution supplied to the set
-
V
1 dm3/h
circulating solution flow rate
-
V
2 dm3/h
volume of solution withdrawn
-
h
time
Abbreviations RBES
rate of bio-oxidation of elemental sulphur 相似文献
15.
J. F. Siebenaller T. F. Murray 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1994,163(8):626-632
To investigate, the effects of hydrostatic pressure on transmembrane signaling in cold-adapted marine fishes, we examined the high-affinity GTPase activity in two congeneric marine fishes, Sebastolobus alascanus and S. altivelis. In brain membranes there are two GTPase activities, one with a low K
m and one with a high K
m for GTP. The high-affinity GTPase activity, characteristic of the subunits of the guanine nucleotide binding protein pool, was stimulated by the A1 adenosine receptor agonists N
6(R-phenylisopropyl)adenosine and N
6-cyclopentyladenosine, and the muscarinic cholinergic agonist carbamyl choline. Pertussis toxin-catalyzed ADP-ribosylation of the membranes for 2 h at 5°C prior to the GTPase assay decreased the basal GTPase activity 30–40% and abolished N
6 (R-phenylisopropyl)adenosine stimulation of GTP hydrolysis. Basal high-affinity hydrolysis of GTP, measured at 0.3 mol·1-1GTP, was stimulated 22% in both species by 340 atm pressure. At 340 atm pressure, the apparent K
m of GTP is decreased approximately 10% in each of the species, and the V
max values are increased 11 and 15.9% in S. alascanus and S. altivelis, respectively. The apparent volume changes associated with the decreased K
m of GTP and the increased V
max ranged from-7.0 to-9.9 ml·mol-1. Increased pressure markedly decreased the efficacy of N
6 (R-phenylisopropyl) adenosine, N
6-cylcopentyladenosine and carbamyl choline in stimulating GTPase activity. The effects of increased hydrostatic pressure on transmembrane signal transduction by the A1 adenosine receptor-inhibitory guanine nucleotide binding protein-adenylyl cyclase system may stem, at least in part, from pressure-increased GTP hydrolysis and the concomitant termination of inhibitory signal transduction.Abbreviations [3H] DPCPX
3H cyclopentyl-1, 3-dipropylxanthine
- AppNHp
5-adenylylimidodiphosphate
- cpm
counts per minute
- CPA
N
6-cyclopentyladenosine
- EDTA
ethylenediaminetetra acetic acid
- EGTA
ethyleneglycol-bis (-aminoethylether) N, N, N, N-totra-acctic acid
- G protein
guanine nucleotide binding protein
- Gi
inhibitory G protein
- Go
other G protein, common in brain membranes
- Gs
stimulatory G protein
- GTPase
guanosine triphosphatase
-
K
i
inhibition constant
-
K
m
Michaelis constant
- pK
a
log of the dissociation constant
- R-PIA
N
6 (R-phenylisopropyl) adenosine
- TRIS
tris[hydroxymethyl]aminomethane
- Vmax
maximal velocity
- [-32P]GTP
[-32P] guanosine 5-triphosphate (tetra (triethylammonium) salt) 相似文献
16.
Inoculation of sugar mill by-products compost with N2-fixing bacteria may improve its quality by increasing total N and available P. Compost was inoculated with Azotobacter vinelandii(ATCC 478), Beijerinckia derxii (ATCC 49361), and Azospirillumsp. TS8, each alone and all three together. Numbers of all N2-fixing bacteria in compost declined from an initial population of 5×105cellsg–1 during incubation. The population of Azotobacter declined to approximately 2×102cellsg–1 and the population of Beijerinckia and Azospirillum declined to approximately 9×103 and 3.5×104cellsg–1 respectively, at day 50. Inoculation with N2-fixing bacteria increased acetylene reduction, total N by 6–16 and available P by 25–30% in comparison to the uninoculated control. Increasing the N content and P availability of compost increases its value and there may be additional benefit from providing N2 fixing bacteria. 相似文献
17.
Premise
While angiosperms respond uniformly to abscisic acid (ABA) by stomatal closure, the response of ferns to ABA is ambiguous. We evaluated the effect of endogenous ABA, hydrogen peroxide (H2O2), nitric oxide (NO), and Ca2+, low and high light intensities, and blue light (BL) on stomatal opening of Pleopeltis polypodioides.Methods
Endogenous ABA was quantified using gas chromatography-mass spectrometry; microscopy results and stomatal responses to light and chemical treatments were analyzed with Image J.Results
The ABA content increases during initial dehydration, peaks at 15 h and then decreases to one fourth of the ABA content of hydrated fronds. Following rehydration, ABA content increases within 24 h to the level of hydrated tissue. The stomatal aperture opens under BL and remains open even in the presence of ABA. Closure was strongly affected by BL, NO, and Ca2+, regardless of ABA, H2O2 effect was weak.Conclusions
The decrease in the ABA content during extended dehydration and insensitivity of the stomata to ABA suggests that the drought tolerance mechanism of Pleopeltis polypodioides is independent of ABA.18.
Takashi Horiuchi Tetsuji Nagasawa Kyoko Takano Mutsuo Sekiguchi 《Molecular & general genetics : MGG》1987,206(2):356-357
Summary We report a new tRNA
1
Asp
gene near the dnaQ gene, which is located at 5 min on the Escherichia coli linkage map. We named it aspV. The sequence corresponding to the mature tRNA is identical with that of the two previously identified tRNA
1
Asp
genes (aspT and aspU), but there is no homology in the sequences of their 3-and 5-flanking regions.Abbreviations kb
kilo base pair(s)
- rrn
ribosomal RNA 相似文献
19.
Prof. Dr. W. -D. Deckwer J. -Q. Yuan K. -H. Bellgardt W. -S. Jiang 《Bioprocess and biosystems engineering》1991,6(6):265-272
A cell cycling model for unequal budding yeast Saccharomyces cerevisiae is proposed and verified by steady state data from experiments available in the literature. This model can be used to determine the relative fraction of the cells in any cycling phase or with any genealogical age during fermentation. As the quality of yeast is strongly influenced by the cycling process, the model could therefore be used to control the quality of the harvested yeast cells. The input of the cell cycling model is the specific growth rate , which is obtained from a metabolic model for S. cerevisiae proposed earlier. With this extended model system not only the quality control, but also the whole economical profit optimization can be carried out. Simulations were done to optimize the profit of a commercial scale baker's yeast production process by manipulating substrate feeding rate and substrate concentration under different aeration rates, fermentation periods and other conditions applied in industry.List of Symbols
B h
budding phase
-
C
d1, C
d2, C
p1'
parameters in cycling phase equations
-
C
p2, C
b1, C
b2, d
s
m
Sauter-diameter
-
E kg/m3
ethanol concentration
-
E1, E2
state variables in the metabolic model
-
E
G
mean relative gas hold-up
-
f
parameter vector of the regulation model
-
F
system matrix of the regulation model
-
F or F(t) m3/h
substrate feeding rate
-
Fr
Froude number
-
FBC, FDC, FPC %
fraction of daughter cells, unbudded daughter cells and unbudded parent cells
-
g m/s2
acceleration of gravity
-
K
B1–3, K
EG
parameters in metabolic model
-
K
3, K
Ad
, L
3
K
3
E, KO, KS
limitation constants for ethanol, oxygen and substrate
-
k
La h–1
volumetric mas transfer coefficient
-
m
ATP
mol(gh)–1
maintenance coefficient
-
nb, nd, np
number of cycling age intervals in budding cycling phase, unbudded daughter cycling phase and unbudded parent cycling phase
-
Nt
number of total cells
-
OF mg/dm3
concentration of dissolved oxygen
-
P kg
total yeast product in dry weight
-
P/O
effectiveness of oxidative phosphorylation
-
q
O20 mol(gh)–1
minimum specific oxygen uptake ability
-
q
O2 mol(gh)–1
specific oxygen uptake rate
-
q
O2max
mol(gh)–1
maximum q
O2 given by metabolic regulation
-
q
s
mol(gh)–1
specific glucose uptake rate
-
q
Smax
mol(gh)–1
maximum q
S
-
R(·)
switch function
-
r
Ac
mol(gh)–1
specific acetyl-CoA-consumption rate
-
r
Acmax
saturation rate of r
Ac
-
r
E1 mol(gh)–1
specific ethanol production rate
-
r
E2 mol(gh)–1
specific ethanol uptake rate
-
r
SO
mol(gh)–1
minimum value of r
Smax
-
r
s
mol(gh)–1
specific rate of glycolysis
-
r
Smax
mol(gh)–1
maximum specific rate of gluconeogenesis given by metabolic regulation
-
S kg/m3
total reduced sugar concentration
-
S
R
kg/m3
substrate concentration in feed
-
T h
cell number doubling time
-
T
f
h
fermentation period
-
Ud h
unbudded daughter phase
-
Up h
unbudded parent phase
-
V
F
m3
volume of liquid phase in fermentor
-
V
G
m3/h
aeration rate
-
w
sg
m/s
superficial gas velocity
-
X kg/m3
dried cell concentration
-
Y
ATP
g(molATP)–1
yield coefficient of ATP
-
z
state vector in regulation model
-
the factor of fermentative activity decrease caused by budding cells
-
or(t) h–1
specific growth rate
-
h
discrete unit of cycling age 相似文献
20.
A. Illanes A. Ruiz M. E. Zúñiga C. Aguirre S. O'Reilly E. Curotto 《Bioprocess and biosystems engineering》1990,5(6):257-262
The production of lactose-based sweeteners is considered very promising. Fungal lactase has been immobilized on crosslinked chitin to develop a process for the continuous hydrolysis of demineralized whey permaete. The optimization of lactase immobilization on chitin and chitosan was performed, activities of 4 · 105 and 2.2 · 105 u/kg at yields of 33 and 23% were obtained for both supports, respectively. The chitin based catalyst was selected for further studies and a procedure was developed for in-situ enzyme immobilization. The kinetic behaviour of the catalyst was determined to propose a kinetic model for the initial rate of lactose hydrolysis. Pseudo steady-state and long term operation of packed bed reactors with chitin-immobilized lactase ranging from small laboratory to pre-pilot unit was carried out. The results are discussed and compared with commercial immobilized lactases. Preliminary economic evaluation for the production of ultrafiltered whey protein and hydrolyzed lactose syrup, within a dairy industry in Chile, was satisfactory in terms of profitability, both for the chitin immobilized lactase developed and for a commercial immobilized lactase.List of Symbols
a moles/m3
glucose concentration in Eq. (1)
-
C
i US$
total annual cost (without considering plant depreciation)
-
D US$
annual depreciation
-
F m3/h
flowrate
-
h m3/h
volumetric mass transfer coefficient
-
i moles/m3
galactose concentration in Eqs. (1) and (2)
-
K
A moles/m3
dissociation constant for glucose in Eq. (1)
-
K
A
moles/m3
dissociation constant for glucose in Eq. (1)
-
K
I moles/m3
inhibition constant for galactose in Eqs. (1) and (2)
-
K
m moles/m3
Michaelis constant for substrate in Eqs. (1) and (2)
-
k
D h–1
first-order thermal deactivation constant
-
P kg
dry weight of catalyst
-
PV US$
net present value
-
R %
discounted cash-flow rate of return
-
s moles/m3
substrate concentration
- s0
moles/m3 feed substrate concentration
-
S
n US$
annual sales income
-
TC US$
total capital income
-
t
1/2 h
catalyst half-life
-
v moles/h · kg
initial rate of reaction
-
V
MAX moles/h · kg
maximum reaction rate in Eqs. (1) and (2)
- V
MAX
moles/h · kg
maximum reaction rate in Eq. (1)
-
¯V
max
moles/h
initial rate of reaction
-
V
R
m3
reaction volume free of catalyst particles
-
X
substrate degree of conversion = s0–s/s0
-
Damkoehler number = ¯V
MAX
/h k
m
- moles/(m3 · h)
reactor productivity in Eq. (3) 相似文献