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1.
W. C. Wells G. C. Weiser 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1989,78(3):365-368
Summary Breeders of self-pollinated legumes commonly use single-seed descent (SSD) or pod-bulk descent (PBD) to produce segregating populations of highly inbred individuals. We presented equations for the expected value of the additive genetic variance within populations derived by SSD (E(V
A)SSD) and PBD (E(V
A)PBD) in terms of the initial population size (N
0), the number of seed harvested per pod (M), the probability of survival of an individual (), and the generation at which the population is evaluated (S
t). Differences between (E(V
A)SSD) and (E(V
A)PBD) are due to differences in the expected amount of random drift which occurs with the two methods after the S
0 generation. With both methods, random drift occurs when progeny are sampled from heterozygous parents. An additional component of random drift occurs when sampled progeny fail to survive during SSD, or when sampling occurs amoung families during PBD. For values of N
0, M, , and S
t that are typical of soybean (Glycine max (L.) Merr.) breeding programs, (E(V
A)SSD) will be greater than (E(V
A)PBD). The ratio of (E(V
A)SSD) to (E(V
A)PBD) will: (1) increase as M and increase; (2) approach a value of 1.00 as N
0 increases; and (3) be a curvilinear function of S
t. Plant breeders should compare SSD and PBD based upon values of (E(V
A)SSD) and (E(V
A)PBD) and the expected cost of carrying out the two methods.Contribution No. 2910 of the South Carolina Agricultural Experiment Station, Clemson University 相似文献
2.
M. L. F. Giuseppin 《Applied microbiology and biotechnology》1984,20(3):161-165
Summary The influence of the concentration of oxygen on lipase production by the fungus Rhizopus delemar was studied in different fermenters. The effect of oxygen limitation ( 47 mol/l) on lipase production by R. delemar is large as could be demonstrated in pellet and filamentous cultures. A model is proposed to describe the extent of oxygen limitation in pellet cultures. Model estimates indicate that oxygen is the limiting substrate in shake flask cultures and that an optimal inoculum size for oxygen-dependent processes can occur.Low oxygen concentrations greatly negatively affect the metabolism of R. delemar, which could be shown by cultivation in continuous cultures in filamentous growth form (Doptimal=0.086 h-1). Continuous cultivations of R. delemar at constant, low-oxygen concentrations are a useful tool to scale down fermentation processes in cases where a transient or local oxygen limitation occurs.Symbols and Abbreviations CO
Oxygen concentration in the gas phase at time = 0 (kg·m-3)
- CO
2i
Oxygen concentration at the pellet liquid interface (kg·m-3)
- CO
2i
Oxygen concentration in the bulk (kg·m-3)
-
D
Dilution rate (h-1)
- IDO
2
Diffusion coefficient for oxygen (m2·s-1)
-
dw
Dry weight of biomass (kg)
-
f
Conversion factor (rs
O
2 to oxygen consumption rate per m3) (-)
-
k
Radial growth rate (m·s-1)
-
K
Constant
-
kla
Volumetric mass transfer coefficient (s-1)
-
klA
Oxygen transfer rate (m-3·s-1)
-
kl
Mass transfer coefficient (m·s-1)
-
K
O
2
Affinity constant for oxygen (mol·m-3)
-
K
w
Cotton plug resistance (m-3·s-1)
-
M
Henry coefficient (-)
-
NV
Number of pellets per volume (m-3)
-
R
Radius (m)
-
RO
Radius of oxygen-deficient core (m)
-
RQ
Respiration quotient (mol CO2/mol O2)
-
rs
O
2
Specific oxygen consumption rate per dry weight biomass (kg O2·s-1[kg dw]-1)
-
rX
Biomass production rate (kg·m-3·s-1)
-
SG
Soytone glucose medium (for shake flask experiments)
-
SG
4
Soytone glucose medium (for tower fermenter and continuous culture experiments)
-
V
Volume of medium (m-3)
-
X
Biomass (dry weight) concentration (kg·m-3)
-
XR
o
Biomass concentration within RO for a given X (kg·m-3)
-
Y
O
2
Biomass yield calculated on oxygen (kg dw/kg O2)
-
Thiele modulus
-
Efficiency factor =1-(RO/R)3 (-)
-
Growth rate (m-1·s-1·kg1/3)
-
Dry weight per volume of pellet (kg·m-3) 相似文献
3.
The stability and, consequently, the lifetime of immobilized enzymes (IME) are important factors in practical applications of IME, especially so far as design and operation of the enzyme reactors are concerned. In this paper a model is presented which describes the effect of intraparticle diffusion on time stability behaviour of IME, and which has been verified experimentally by the two-substrate enzymic reaction. As a model reaction the ethanol oxidation catalysed by immobilized yeast alcohol dehydrogenase was chosen. The reaction was performed in the batch-recycle reactor at 303 K and pH-value 8.9, under the conditions of high ethanol concentration and low coenzyme (NAD+) concentration, so that NAD+ was the limiting substrate. The values of the apparent and intrinsic deactivation constant as well as the apparent relative lifetime of the enzyme were calculated.The results show that the diffusional resistance influences the time stability of the IME catalyst and that IME appears to be more stabilized under the larger diffusion resistance.List of Symbols
C
A, CB, CE mol · m–3
concentration of coenzyme NAD+, ethanol and enzyme, respectively
-
C
p mol · m3
concentration of reaction product NADH
-
d
p mm
particle diameter
-
D
eff m2 · s–1
effective volume diffusivity of NAD+ within porous matrix
-
k
d s–1
intrinsic deactivation constant
-
K
A, KA, KB mol · m–3
kinetic constant defined by Eq. (1)
-
K
A
x
mol · m–3
kinetic constant defined by Eq. (5)
-
r
A mol · m–3 · s–1
intrinsic reaction rate
-
R m
particle radius
-
R
v mol · m–3 · s–1
observed reaction rate per unit volume of immobilized enzyme
-
t
E s
enzyme deactivation time
-
t
r s
reaction time
-
V mol · m–3 · s–1
maximum reaction rate in Eq. (1)
-
V
x mol · m–3 · s–1
parameter defined by Eq. (4)
-
V
f m3
total volume of fluid in reactor
-
w
s kg
mass of immobilized enzyme bed
-
factor defined by Eqs. (19) and (20)
-
kg · m–3
density of immobilized enzyme bed
-
unstableness factor
-
effectiveness factor
-
Thiele modulus
-
relative half-lifetime of immobilized enzyme
Index
o
values obtained with fresh immobilized enzyme 相似文献
4.
Allometric aspects of population dynamics: A symmetry approach 总被引:1,自引:0,他引:1
E. L. Charnov 《Evolutionary ecology》1992,6(4):307-311
Summary The maximum intrinsic rate of increase (r
max
) shows a –0.25 scaling with adult body weight (W) in mammals (and others). Average adult life span (1/M) and age at maturity () show –0.25 scalings, independent of population size; these two lead to ther
max
scaling, providedR
o is invariant with body size in rarified populations (=R
om
). Thus ther
max
scaling follows from the existence of two population size symmetries (i.e. 1/M and ) and one body size symmetry (R
o
). The theory provides a formula to calculate the height (A
3) of the scalingr
max
=A
3
·W
–0.25. The theory also helps to explain Fowler's Rules, which linkR
om
to the relative position of the inflection point of the population growth curve. 相似文献
5.
Miroslav Flieger Jaroslav Votruba Vladimír Křen Sylvie Pažoutová Viktor Rylko Přemysl Sajdl Zdeněk Reháček 《Applied microbiology and biotechnology》1988,29(2-3):181-185
Summary Kinetic parameters of production of clavine alkaloids were evaluated in twoClaviceps purpurea strains. Mutagenesis brought about enhanced resistance of the biosynthetic system towards alkaloids. Addition of glucose into the fermentation medium altered the zero order kinetics of production to activation-inhibition kinetics. The glucose treatment allowed performance of both elymoclavine-inhibitionless and clavine alkaloid-decompositionless fermentations if a combination of fermentation and separation units in a closed loop was used.Nomenlacture
k
1
rate constant of agroclavine synthesis (mg Agro · mg Elymo/l·g DW·day for stage 1, mg Agro/g DW·day for stage 2)
-
k
2
parameter describing inhibition of agroclavine formation rate by elymoclavine (mg Elymo/l)
-
k
3
specific rate of agroclavine decay (l/g DW·day)
-
k
4
maximal specific rate of elymoclavine synthesis (stage 1, 1/g DW·day, stage 2, mg Elymo/g DW·day)
-
k
4
–
maximal specific rate of elymoclavine synthesis in stage 1 (inhibition-activation mechanism) (mg Elymo/g DW·day)
-
k
5
physiological constant describing the elymoclavine decay rate (l2/g DW·day·mg Elymo)
-
k
5
–
physiological constant describing the activation of elymoclavine biosynthesis by elymoclavine (mg Elymo/l)
-
k
6
physiological constant describing the repression of elymoclavine biosynthesis by elymoclavine (mg Elymo/l)
-
k
7
maximal specific growth rate (1/day)
-
k
8
specific rate of biomass decay (l/g DW·day)
-
A
agroclavine concentration (mg/l)
-
E
elymoclavine concentration (mg/l)
-
r
A
specific rate of agroclavine biosynthesis (mg Agro/g DW·day)
-
r
E
specific rate of elymoclavine biosynthesis (mg Elymo/g DW·day)
-
r
i
specific rate of alkaloid biosynthesis (mg alkaloid/g DW·day)
-
X
dry biomass concentration (g/l)
-
specific growth rate (1/day)
Abbreviations Agro
agroclavine
- Elymo
elymoclavine
- Chano
chanoclavine
- DW
dry weight of biomass 相似文献
6.
Summary Penicillin G recovery is investigated in a continuous flotation column in the presence of different collectors which form a complex with penicillin. The performance of the penicillin recovery was investigated as a function of the mole ratio () of collector-to-penicillin and the aliphatic chain length of the collector. At =1 and low penicillin concentrations (e.g., 20 mg·1-1), high foam liquid concentrations (680 mg·l-1), low residue concentrations (12 mg·l-1) and high penicillin separation (56) can be attained. At =4 the separation increases to 150, and 95% of the penicillin can be recovered.Symbols Cp
penicillin concentration in feed (mg·l-1)
- CR
penicillin concentration in outlet liquid (mg·l-1)
- CS
penicillin concentration in foam liquid (mg·l-1)
- CS/CP
penicillin enrichment (-)
- CS/CR
penicillin separation (-)
- %
Pen in S penicillin yield in foam liquid (%)
-
VV}S
foam liquid volume flow (ml·min-1)
-
VV}P
feed (ml·min-1)
-
VVN
2
nitrogen flow rate (ml·s-1)
-
temperature 相似文献
7.
Kam Yeong-Choy Ackerman Ralph A. 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1990,160(3):317-324
Summary The effect of two different incubation media, sand and vermiculite, on the water exchange of eggs and the mass of hatchlings of snapping turtles (Chelydra serpentina) was assessed. The eggs were incubated fully buried in either sand or vermiculite at 30 °C and egg mass was measured periodically throughout incubation. The wet and dry masses of each hatchling and its residual yolk were measured at the end of incubation. The media had similar water potentials () but their thermal conductivities differed 2.8-fold. The eggs experienced a net water gain during incubation. The rates of water uptake between treatments were not statistically different throught the first 36 days of incubation but were statistically different thereafter, with eggs incubating in sand taking up water at about twice the rate of eggs incubating in vermiculite. Hatchling masses were similar to both media but hatchling water contents were significantly different. Hatchlings incubated in sand had lower water contents than hatchlings incubated in vermiculite even though the eggs in sand took up more water. Hatchling mass was correlated with egg water exchange for eggs incubated in vermiculite but not for eggs incubated in sand. The difference in egg water exchange in the two media appears to be attributable to differences in the thermal conductivity of the media. The presence of such a thermal effect supports the hypothesis that the eggs exchanged water with the media as water vapor. Egg water exchange was limited by the shell and shell membranes and not by the media. The shell and shell membranes appear to present an effective barrier to water uptake.Abbreviations
M
H
2
O
water flux (cm3·day-1)
-
L
p
hydraulic conductivity (cm·day-1·kPa-1)
-
A
shell area (cm2)
-
A
p
pore area (cm2)
-
l
shell thickness (cm)
-
r
pore radius (cm)
-
viscosity (kPa·day)
-
P
EH
2
O
egg water potential (kPa)
-
P
AH
2
O
medium water potential (kPa)
-
G
H
2
O
water vapor conductance (cm3·day-1·kPa-1)
-
D
H
2
O
diffusion coefficient (cm2·day-1)
-
R
gas constant (cm3·kPa·K-1·cm-3)
-
T
temperature (K)
-
P
EH
2
O
egg water vapor pressure (kPa)
-
P
AH
2
O
medium water vapor pressure (kPa)
-
d
egg diameter
-
K
soil hydraulic conductivity (cm2·day-1·kPa-1)
-
DHM
hatchling dry mass
-
WHM
hatchiling wet mass
-
WU
water uptake
-
IM
initial egg mass 相似文献
8.
Summary Well watered plants of Vigna unguiculata (L.) Walp cv. California Blackeye No. 5 had maximum photosynthetic rates of 16 mol m-2 s-1 (at ambient CO2 concentration and environmental parameters optimal for high CO2 uptake). Leaf conductance declined with increasing water vapour concentration difference between leaf and air (w), but it increased with increasing leaf temperature at a constant small w. When light was varied, CO2 assimilation and leaf conductance were correlated linearly. We tested the hypothesis that g was controlled by photosynthesis via intercellular CO2 concentration (c
i). No unique relationship between (1) c
i, (2) the difference between ambient CO2 concentration (c
a) and c
i, namely c
a-c
i, or (3) the c
i/c
a ratio and g was found. g and A appeared to respond to environmental factors fairly independently of each other. The effects of different rates of soil drying on leaf gas exchange were studied. At unchanged air humidity, different rates of soil drying were produced by using (a) different soils, (b) different irrigation schemes and (c) different soil volumes per plant. Although the soil dried to wilting point the relative leaf water content was little affected. Different soil drying rates always resulted in the same response of photosynthetic capacity (A
max) and corresponding leaf conductance (g(Amax)) when plotted against percent relative plant-extractable soil water content (W
e
%) but the relationship with relative soil water content (W
e
) was less clear. Above a range of W
e
of 15%–25%, A
max and g(Amax) were both high and responded little to decreasing W
e
. As soon as W
e
fell below this range, A
max and g(Amax) declined. The data suggest root-to-leaf communication not mediated via relative leaf water content. However, g(Amax) was initially more affected than A
max.List of abbreviations
A CO2
assimilation
-
A
max
photosynthetic capacity at favourable ambient conditions
-
c
a CO2
concentration of the air in the leaf chamber
-
c
i
intercellular
- CO2
concentration
-
E
transpiration
-
g
leaf conductance
-
g(Amax)
leaf conductance corresponding to photosynthetic capacity
-
I
photon flux rate
-
T
l
leaf temperature
-
W
e
relative plant-extractable soil water content
-
W
e
absolute plant-extractable soil water content
-
W
l
relative leaf water content
-
W
s
relative soil water content
- w
difference in water vapour mole fraction between leaf and air
-
leaf water potential 相似文献
9.
G. E. Walsberg B. O. Wolf 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1995,165(4):306-314
We quantified metabolic power consumption as a function of wind speed in the presence and absence of simulated solar radiation in rock squirrels, Spermophilus variegatus, a diurnal rodent inhabiting arid regions of Mexico and the western United States. In the absence of solar radiation, metabolic rate increased 2.2-fold as wind speed increased from 0.25 to 4.0 m·s-1. Whole-body thermal resistance declined 56% as wind speed increased over this range, indicating that body insulation in this species is much more sensitive to wind disruption than in other mammals. In the presence of 950 W·m-2 simulated solar radiation, metabolic rate increased 2.3-fold as wind speed was elevated from 0.25 to 4.0 m·s-1. Solar heat gain, calculated as the reduction in metabolic heat production associated with the addition of solar radiation, increased with wind speed from 1.26 mW·g-1 at 0.25 m·s-1 to 2.92 mW·g-1 at 4.0 m·s-1. This increase is opposite to theoretical expectations. Both the unexpected increase in solar heat gain at elevated wind speeds and the large-scale reduction of coat insulation suggests that assumptions often used in heat-transfer analyses of animals can produce important errors.Abbreviations
absorptivity of coat to solar radiation
-
kinematic viscosity of air (mm2·s-1)
-
reflectivity of coat to solar radiation
-
a
r
B
expected at zero wind speed (s·m-1)
-
A
P
projected surface area of animal on plane perpendicular to solar beam (cm2)
-
A
SKIN
skin surface area (cm2)
-
b
Coefficient describing change in r
B with change in square-root of wind speed (s1.5·m1.5)
-
d
hair diameter (m)
- d
characteristic dimension of animal (m)
-
D
H
thermal diffusivity of air (m2·s-1)
-
E
evaporative heat loss (W·m-2)
-
I
probability per unit coat depth that photon will strike hair
-
k
constant equalling 1200 J·m-3·°C-1
-
l
C
coat depth m)
-
l
H
hair length (m)
-
M
metabolic rate (W·m-2)
-
n
density of hairs of skin (m-2)
-
Q
A
solar heat gain to animal (W·m-2)
-
Q
I
solar irradiance intercepted by animal (W·m-2)
-
RQ
respiratory quotient
-
r
A
thermal resistance of boundary layer (s·m-1)
-
r
B
whole-body thermal resistance (s·m-1)
-
r
E
thermal resistance between animal surface and environment s·m-1)
-
r
R
radiative resistance (s·m-1)
-
r
S
sum of r
B and r
E at 0.25 m·s-1 (s·m-1)
-
r
T
tissue thermal resistance s·m-1)
-
T
AIR
air temperature (°C)
-
T
B
body temperature (°C)
-
T
E
operative temperature of environment (°C)
-
T
ES
standard operative temperature of environment (°C)
-
u
wind speed (m·s-1) 相似文献
10.
Paolo Cerretelli Bruno Grassi Lei Xi Federico Schena Claudio Marconi Michael Meyer Guido Ferretti 《European journal of applied physiology and occupational physiology》1995,71(4):287-294
To gain an insight into the origin of the phase I ventilatory response to exercise (ph I) in humans, pulmonary ventilation WE) and end-tidal partial pressures of oxygen and carbon dioxide (P
ETO2 and P
ETCO2, respectively) were measured breath-by-breath in six male subjects during constant-intensity exercise on the cycle ergometer at 50, 100 and 150 W, with eupnoeic normocapnia (N) or hyperpnoeic hypocapnia (H) established prior to the exercise test. Cardiac output (Q2) was also determined beat-by-beat by impedance cardiography on eight subjects during moderate exercise (50 W), and the C02 flow to the lungs (Q2·CvCO2 where CvCO2 is concentration of CO2 in mixed veneous blood) was estimated with a time resolution of one breathing cycle. In N, the initial abrupt increase of PE during ph I (VE approximately 18 l · min–1 above rest) was followed by a transient fall. When P
ETCO2 started to increase (and P
ETO2 decreased) VE increased again (phase II ventilatory response, ph II). In H, during ph I VE was similar to that of N. By contrast, during ph II VE kept gradually decreasing and started to increase only when P
ETCO2 had returned to approximately 40 mmHg (5.3 kPa). Thus, as a result of the prevailing initial conditions (N or H) a temporal shift of the time-course of VE during ph II became apparent. No correlation was found between C02 flow to the lungs and VE during ph I. These results are interpreted as suggesting that an increased C02 flow to the lungs does not constitute an important factor for the initial hyperventilatory response to exercise. They are rather compatible with a neural origin of ph I, and would support the neurohumoral theory of ventilatory control during exercise. 相似文献
11.
Hans-Ulrich Meisch Helga Benzschawel Hans-Joachim Bielig 《Archives of microbiology》1977,114(1):67-70
Cells of Chlorella pyrenoidosa, derived from vanadium free agar slants, respond with great sensitivity to microamounts of vanadium, added as NH4VO3 to autotrophic liquid cultures. Between 0.01 and 1 g V per litre nutrient medium (2·10-10-2·10-8g-at/l), the algae respond with a continuous increase in dry weight. At higher V-concentrations, further enhancement in biomass is accompanied by a additional increase in chlorophyll content. Maximum V-effect on both parameters was found to be at 500g V/l (10-5 g-at/l). Dry weight as well as chlorophyll content of Chlorella are decreased by concentrations above 25 mg V/l; 100 mg V/l (2·10-3 g-at/l) stop growth and cause death of the cells. The toxic threshold for the V-content in the algae was determined to be at 150–200 g V/g (3–4·10-6 g-at/g) dry weight.Two different pH-optima for a positive vanadium action on dry weight and chlorophyll biosynthesis were established, the first at pH 7, the other in the range pH 7.5–8. Two sites of vanadium action in green algae are discussed.Part I: Arch. Microbiol. 105, 77–82 (1975) 相似文献
12.
The ecology of Lake Nakuru (Kenya) 总被引:11,自引:0,他引:11
Summary Consumer biomass and spatial distribution in the equatorial alkaline-saline Lake Nakuru were studied from 1972–1976. These data will provide the basis for estimating feeding and production rates and for quantifying energy flow at the consumer level. Two of the main consumers, the Lesser Flamingo (Phoeniconaias minor) and the Soda Tilapia (Sarotherodon alcalicus grahami), were covered by earlier papers. The biomass of the only planktonic crustacean, the copepod Lovenula (=Paradiaptomus) africana was very high (1.5 gDW (dry weight)·m-3, mean in 1972/73) in comparison with other tropical lakes. Lovenula was absent in 1974 and 1975, and at very low levels (0.1–0.4 gDW·m-3) in part of 1976. Among the rotifers Brachionus dimidiatus dominated in 1972/73 (0.2 gDW· m-3), but was outnumbered by B. plicatilis throughout most of 1974 to 1976 (mean total rotifer biomass 1.4 gDW· m-3, peak densities 7 gDW·m-3); during high salinity periods (>20) Hexarthra jenkinae occurred in very low numbers. For short periods rotifers can be the dominant species of L. Nakuru. Aquatic heteroptera (four species) played a minor role: they contributed 0.4% to total consumer biomass in 1972/73; in 1974–1976 the lake had no aquatic heteroptera. Benthic biomass (0.4 gDW·m-2) was within the range of other tropical lakes, it consisted almost exclusively of Leptochironomus deribae. Bird counts of the twelve most important species are given for the years 1972–1974: Pelecanus onocrotalus accounts for 90% of the biomass (0.44 gDW·m-3, mean 1972/73) with peak densities of almost 20,000 birds.-The consumer organisms covered by this and the two preceding papers represent >99% of L. Nakuru's consumer biomass. Population dynamics of various consumer species are discussed. 相似文献
13.
A. Laurence Santerre I. Queinnec P. J. Blanc 《Bioprocess and biosystems engineering》1995,13(5):245-250
According to the measurement of the pigment production and some material balance treatments, the monosodium glutamate (MSG), which represents a main substrate involved in the production of red pigment by Monascus ruber, is recovered on-line. Fedbatch operation then represents an alternative for increasing the production of pigment. A nonlinear quotient control scheme is expressed to regulate the monosodium glutamate substrate at an optimal value determined from batch studies.List of Symbols
A
absorbancy units (AU)
-
L
lightness parameter
-
Pig
red pigment quantity (Gmol)
-
vol
fermentor active volume (1)
-
empirical coefficient
-
MW
pig
red pigment molecular weight (g)
-
E
elementary matrix
-
E
#
pseudo-inverse elementary matrix
-
r
conversion rates vector (g· l–1·h–1)
-
E
m
measured part of the elementary matrix
-
r
m
measured conversion rates vector
-
E
c
non-measured part of the elementary matrix
-
r
c
non-measured conversion rates vector
-
v
fictitious controller input
-
h
fictitious controller output
-
u
controller input
-
y
controller output
-
y
controller setpoint
-
k
1
controller parameter
-
k
2
controller parameter
-
k
time iteration
-
MSG
monosodium glutamate concentration (g·l–1)
-
MSG
init
monosodium glutamate initial quantity (g)
-
MSG
added
total quantity of monosodium glutamate added (g)
-
MSG
cons
total quantity of monosodium glutamate consumed (g)
-
MW
msg
monosodium glutamate molecular weight (g) 相似文献
14.
J. P. R. Ochieng'-Odero 《Entomologia Experimentalis et Applicata》1990,54(1):21-27
Adult reproductive performance is linked to the period of feeding done by the final instar larva after attainment of a larval critical weight (LCW). The highest weight attained by a final instar larva is referred to as the larval maximum weight (LMW) and is the onset of the pre-pupal period. The relationships between LCW, pupal weight (PW) and adult weight (AW) are described as functions of the LMW. In the leafroller Cnephasia jactatana (Walker) (Lepidoptera: Tortricidae) LCW was dependent on larval size and was approximately 75% of the mean LMW. LCW was about 29 mg and 36 mg for male and female larvae of 1.18 mm and 1.20 mm head-capsule width, respectively. Over three successive generations of laboratory rearing, PW was approximately 30% and 25% lower than the LMW for males and females, respectively. AW was consistently about 50% and 40% lower than the PW for males and females, respectively. The decrease in weight from LMW to PW was named as the constant DP and found to be 0.3 for males and 0.25 for females. The total decrease from LMW to AW was the constant DA and was 0.6 for males and 0.5 for females. The duration of the latent feeding period was positively correlated to PW and AW. LCW may be used to derive quality indices that describe and predict pupal and adult performance.
Résumé Les performances reproductives sont liées à la période d'alimentation du dernier stade larvaire après l'obtention d'un poids critique (LCW). Le poids maximal atteint au dernier stade larvaire est défini comme le poids larvaire maximal (LMW), il correspond au début de la période prénymphale. Les relations entre poids de la chrysalide (PW) et poids de l'audulte AW) sont présentées comme des fonctions de LMW). Chez Cnephasia jactatana Walker (Lep. Tortricidae), LCW dépend de la taille de la chenille et correspond à environ 75% de la valeur moyenne de LMW. LCW est respectivement de 29 mg et 36 mg pour les chenilles mâles et femelles dont les capsules céphaliques ont 1,18 et 1,20 mm. Pour 3 générations successives, PW est environ 30% et 25% inférieur à LMW des mâles et des femelles. La régression du poids de LMW à PW est désignée comme la constante DP et vaut 0,3 pour les mâles et 0,25 pour les femelles. La régression de LMW à AW est désignée comme la régression DM et vaut 0,6 pour les mâles et 0,5 pour les femelles. La durée de la période d'alimentation latente est liée positivement à PW et AW. LCW peut être utilisé comme indice dérivé décrivant et prédisant les potentialités nymphales et imaginales.相似文献
15.
Changes in dry weight, carbon, nitrogen, hydrogen and ash content of the rotifer Brachionus plicatilis were investigated during population growth in culture. Also caloric equivalent was estimated from carbon content. Body dry weight and weight of C, N, and H increased with increasing the egg/female ratio of the population, while ash content remained constant. As percentage of dry weight, C content increased with fecundity, H and N remained constant and ash content decreased. The caloric equivalent ranged from 1278 µcal to 4406 µcal for rotifers from 314 µg to 846 µg of dry weight. 相似文献
16.
The additive genetic variance with respect to absolute fitness, VA(W), divided by mean absolute fitness, , sets the rate of ongoing adaptation. Fisher''s key insight yielding this quantitative prediction of adaptive evolution, known as the Fundamental Theorem of Natural Selection, is well appreciated by evolutionists. Nevertheless, extremely scant information about VA(W) is available for natural populations. Consequently, the capacity for fitness increase via natural selection is unknown. Particularly in the current context of rapid environmental change, which is likely to reduce fitness directly and, consequently, the size and persistence of populations, the urgency of advancing understanding of immediate adaptive capacity is extreme. We here explore reasons for the dearth of empirical information about VA(W), despite its theoretical renown and critical evolutionary role. Of these reasons, we suggest that expectations that VA(W) is negligible, in general, together with severe statistical challenges of estimating it, may largely account for the limited empirical emphasis on it. To develop insight into the dynamics of VA(W) in a changing environment, we have conducted individual-based genetically explicit simulations. We show that, as optimizing selection on a trait changes steadily over generations, VA(W) can grow considerably, supporting more rapid adaptation than would the VA(W) of the base population. We call for direct evaluation of VA(W) and in support of prediction of rates adaptive evolution, and we advocate for the use of aster modeling as a rigorous basis for achieving this goal. 相似文献
17.
Bernhard Hoffmann Isolde Nagel Wolfgang Clauss 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1990,160(4):381-388
Summary Regulation of the paracellular pathway in rabbit distal colon by the hormone aldosterone was investigated in vitro in Ussing chambers by means of transepithelial and microelectrode techniques. To evaluate the cellular and paracellular resistances an equivalent circuit analysis was used. For the analysis the apical membrane resistance was altered using the antibiotic nystatin. Under control conditions two groups of epithelia were found, each clearly dependent on the light: dark regime. Low-transporting epithelia (LT) were observed in the morning and high-transporting epithelia (HT) in the afternoon. Na+ transport was about 3-fold higher in HT than in LT epithelia. Incubating epithelia of both groups with 0.1 mol·1-1 aldosterone on the serosal side nearly doubled in LT epithelia the short circuit current and transepithelial voltage but the transepithelial resistance was not influenced. Maximal values were reached after 4–5 h of aldosterone treatment. In HT epithelia due to the effect of aldosterone all three transepithelial parameters remained constant over time. Evaluation of the paracellular resistance revealed a significant increase after aldosterone stimulation in both epithelial groups. This increase suggests that tight junctions might have been regulated by aldosterone. The hormonal effect on electrolyte transport was also dependent on the physiological state of the rabbit colon. Since net Na+ absorption in distal colon is, in addition to transcellular absorption capacity, also dependent on the permeability of the paracellular pathway, the regulation of tight junctions by aldosterone may be a potent mechanism for improving Na+ absorption during hormone-stimulated ion transport.Abbreviations
V
t
transepithelial potential difference (mV)
-
R
t
transepithelial resistance (·cm2)
-
G
t
transepithelial conductance (mS·cm-2)
- Isc
calculated short circuit current (A·cm-2)
-
V
a
apical membrane potential difference (mV)
-
V
bl
basolateral membrane potential difference (mV)
-
voltage divider ratio
-
R
a
apical membrane resistance (·cm2)
-
R
bl
basolateral membrane resistance (·cm2)
-
R
c
cellular resistance ( of apical and basolateral resistance) (·cm2)
-
R
p
resistance of the paracellular pathway (·cm2)
-
G
a
apical membrane conductance (mS·cm-2)
-
G
bl
basolateral membrane conductance (mS·cm-2)
-
G
p
paracellular conductance (mS·cm-2)
-
G
t
transepithelial conductance (mS·cm-2)
-
HT
contr
high transporting control epithelia
-
LT
contr
low transporting control epithelia
-
HT
aldo
aldosterone incubated high transporting epithelia
-
LT
aldo
aldosterone incubated low transporting epithelia 相似文献
18.
Evidence is presented that the high levels of internal l-glutamic and l-aspartic acid in frog Rana esculenta red blood cells are due to the existence of a specific carrier for acidic amino acids of high affinity K
m
= 3 m and low capacity (Vmax) 0.4 mol l-Glu · Kg–1 dry cell mass · 10 min–1. It is Na+ dependent and the incorporation of l-glutamic acid can be inhibited by l and d-aspartate and l-cysteic acid, while d-glutamic does not inhibit. Moreover, this glutamic uptake shows a bell-shaped dependence on the external pH. All these properties show that this carrier belongs to the system X
AG
–
family. Besides the incorporation through this system, l-glutamic acid is also taken up through the ASC system, although, under physiological conditions, this transport is far less important, since it has relatively low affinity K
m 39 m but high capacity (V
max) 1.8 mol l-Glu · Kg–1 dry cell mass · 10 min–1. 相似文献
19.
Biomass Partitioning and Gas Exchange in Dalbergia sissoo seedlings under water stress 总被引:3,自引:0,他引:3
Biomass, leaf water potential (l), net photosynthetic rate (P
N), transpiration rate (E), stomatal conductance (g
s), leaf to air temperature difference (T
diff), and instantaneous water use efficiency (WUE) were measured in the seedlings of Dalbergia sissoo Roxb. grown under irrigation of 20 (W1), 14 (W2), 10 (W3), and 8 (W4) mm. Treatments were maintained by re-irrigation when water content of the soil reached 7.4% in W1, 5.6% in W2, 4.3% in W3, and 3.2% in W4. Seedlings in a control (W5) were left without irrigation after maintaining the soil field capacity (10.7%). Seedlings of W1 had highest biomass that was one tenth in W5. Biomass allocation was highest in leaf in W2 and in root in W4 and W5 treatments. Difference between predawn leaf water potential (Pd) and midday (mid) increased with soil water stress and with vapour pressure deficit (VPD) in April and May slowing down the recovery in plant leaf water status after transpiration loss. P
N, E, and g
s declined and T
diff increased from W1 to W5. Their values were highly significant in April and May for the severely stressed seedlings of W4 and W5. P
N increased from 08:00 to 10:00 and E increased until 13:00 within the day for most of the seedlings whereas g
s decreased throughout the day from 08:00 to 17:00. P
N and E were highest in March but their values were low in January, February, April, and May. Large variations in physiological variables to air temperature, photosynthetically active radiation, and vapour pressure deficit (VPD) indicated greater sensitivity of the species to environmental factors. WUE increased from W1 to W2 but decreased drastically at high water stress particularly during hot summer showing a kind of adaptation in D. sissoo to water stress. However, low biomass and reduced physiological functions at <50% of soil field capacity suggest that this species does not produce significant biomass at severe soil water stress or drought of a prolonged period. 相似文献
20.
S. F. Perry 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1990,159(6):761-769
Summary The respiratory surface area (SAR) per kilogram body mass (MB), the harmonic mean thickness of the air-blood barrier (htR) in the gas exchange tissue, and the anatomical diffusion factor (ADF=SAR/htR per MB) were calculated for four juvenile Nile crocodiles. The ADF of three small specimens (mean MB=3.59 kg) was 625 cm2·m–1·kg–1. The values varied considerably among individuals and were similar to that of a 5.68-kg specimen (593 cm2·m–1·kg–1). Only 9% of the ADF is located in the anterior third of the lung, which because of its conical shape makes up only 14 percent of the total lung volume. Particularly in the middle third of the lung, the proximal region near the intrapulmonary bronchus displays a greater ratio of respiratory/non-respiratory surface areas than do more distally located sampling sites. The htR is also significantly smaller proximally than distally. The cumulative ADF per unit MB is greater than that previously reported for this species on the basis of overall estimates of SAR and htR, but is still less than that of lizards and testudinids. The disposition of ADF between distal air storage region and the intrapulmonary bronchus is consistent with a bidirectional cross-current gas exchange model.Abbreviations
ADF
anatomical diffusion factor
- %AR
percent of SA included in the effective respiratory zone
-
M
B
body mass
-
NVP
non-ventilatory period
- %P
percent of total lung volume containing parenchyma
-
S
A
total surface area of intrapulmonary septa
-
S
ANR
that portion ofS
A
lying out the effective respiratory zone
-
S
V
surface-to-volume ratio in the parenchyma
- htR
harmonic mean thickness of the air-blood tissue barrier within the respiratory zone
-
V
P
parenchymal volume
-
VP
ventilatory period 相似文献