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1.
Robert Biedermann 《Global Ecology and Biogeography》2003,12(5):381-387
Aim This paper tests firstly for the existence of a general relationship between body size of terrestrial animals and their incidence across habitat patches of increasing size, and secondly for differences in this relationship between insects and vertebrates. Location The analysis was based on the occupancy pattern of 50 species from 15 different landscapes in a variety of ecosystems ranging from Central European grassland to Asian tropical forest. Methods The area‐occupancy relationship was described by incidence functions that were calculated using logistic regression. A correlation analysis between body size of the species and the patch area referring to the two given points of the incidence function was performed. In order to test for an effect of taxon (insects vs. vertebrates), an analysis of covariance was conducted. Results In all species, the incidence was found to increase with increasing patch area. The macroecological analysis showed a significant relationship between the incidence in habitat patches and the body size of terrestrial animals. The area requirement was found to increase linearly with increasing body size on a log‐log scale. This relationship did not differ significantly between insects and vertebrates. Conclusions The approach highlighted in this paper is to associate incidence functions with body size. The results suggest that body size is a general but rather rough predictor for the area requirements of animals. The relationship seems valid for a wide range of body sizes of terrestrial animals. However, further studies including isolation of habitats as well as additional species traits into the macroecological analysis of incidence functions are needed. 相似文献
2.
The effects of mispair and nonpair correction in hybrid DNA on base ratios (G + C content) and total amounts of DNA 总被引:1,自引:0,他引:1
Base ratios and total DNA amounts can vary substantially between and within
higher taxa and genera, and even within species. Gene conversion is one of
several mechanisms that could cause such changes. For base substitutions,
disparity in conversion direction is accompanied by an equivalent disparity
in base ratio at the heterozygous site. Disparity in the direction of gene
conversion at meiosis is common and can be extreme. For transitions (which
give purine [R]/pyrimidine [Y] mispairs) and for transversions giving
unlike R/R and Y/Y mispairs in hybrid DNA, this disparity could give slow
but systematic changes in G + C percentage. For transversions giving like
R/R and Y/Y mispairs, it could change AT/TA and CG/GC ratios. From the
extent of correction direction disparity, one can deduce properties of
repair enzymes, such as the ability (1) to excise preferentially the purine
from one mispair and the pyrimidine from the other for two different R/Y
mispairs from a single heterozygous site and (2) to excise one base
preferentially from unlike R/R or Y/Y mispairs. Frame-shifts usually show
strong disparity in conversion direction, with preferential cutting of the
nonlooped or the looped-out strand of the nonpair in heterozygous h-DNA.
The opposite directions of disparity for frame-shifts and their intragenic
suppressors as Ascobolus suggest that repair enzymes have a strong,
systematic bias as to which strand is cut. The conversion spectra of
mutations induced with different mutagens suggest that the nonlooped strand
is preferentially cut, so that base additions generally convert to mutant
and deletions generally convert to wild-type forms. Especially in
nonfunctional or noncoding DNA, this could cause a general increase in DNA
amounts. Conversion disparity, selection, mutation, and other processes
interact, affecting rates of change in base ratios and total DNA.
相似文献
3.
J. Oelze M. Biedermann Elisabeth Freund-Mölbert G. Drews 《Archives of microbiology》1969,66(2):154-165
Zusammenfassung Der Zusammenhang zwischen dem spezifischen Bacteriochlorophyllgehalt der Zellen und der Thylakoidmorphogenese wird an Rhodospirillum rubrum untersucht. Bei der Induktion des Photosynthese-Apparates wird zunächst Bacteriochlorophyll synthetisiert, obgleich noch keine Thylakoide gebildet werden (1. Phase). Werden Thylakoide ausgebildet, so steigt der spezifische Bacteriochlorophyllgehalt der Thylakoide in Abhängigkeit vom spezifischen Bacteriochlorophyllgehalt der Zellen an, bis ein Wert von 12–13 g Bacteriochlorophyll je mg Zellprotein erreicht ist (2. Phase). Während der Wert für die Zellen darüber hinaus weiter erhöht werden kann, bleibt der Wert der Thylakoide konstant bei 100 g Bacteriochlorophyll je mg Thylakoid-Protein (3. Phase). Isolierte Thylakoide aus Zellen mit niedrigem Bacteriochlorophyllgehalt besitzen geringere Durchmesser als Thylakoide aus Zellen mit höheren Werten. Auch hinsichtlich der Zusammensetzung der Thylakoide in Abhängigkeit von den steigenden Bacteriochlorophyllgehalten bei induzierten Zellen konnten Unterschiede festgestellt werden. Ähnlich wie die spezifischen Bacteriochlorophyllgehalte der Thylakoide, nähern sich die verschiedenen Proteinbausteine der Thylakoide einem festen Verhältnis zueinander, das sich oberhalb von 10–14 g Bacteriochlorophyll je mg Zellprotein nicht mehr ändert. Mit Zunahme des Bacteriochlorophyllgehaltes der Zellen steigt der Gehalt an thylakoidspezifischen Proteinen in den Membranen an und der Anteil der für die Cytoplasmamembran spezifischen Komponenten nimmt ab.
Verwendete Abkürzungen BChl. Bacteriochlorophyll 相似文献
The bacteriochlorophyll content and protein composition of chromatophores (=thylakoids) of Rhodospirillum rubrum during morphogenesis of the photosynthetic apparatus
Summary The correlation between the specific bacteriochlorophyll content of whole cells and the morphogenesis of chromatophores was investigated in Rhodospirillum rubrum. During the first phase after induction of the photosynthetic apparatus bacteriochlorophyll is synthesized without formation of chromatophores. In a second phase chromatophores increases in a linear correlation to the specific bacterichlorophyll content of the cells. In a third phase, when the specific bacteriochlorophyll content of the cells has reached 12–13 g/mg protein, the specific bacteriochlorophyll content of the chromatophores remains constant (100 g/mg protein). Isolated chromatophores from the second phase have smaller diameters, than chromatophores from the third phase. The composition of the protein compounds of isolated chromatophores changes during the development of the chromatophores in a similar fashion as the specific bacteriochlorophyll content of chromatophores does change. With increasing bacteriochlorophyll content of the cells the chromatophore specific proteins in the membranes increase whereas proteins specific for the cytoplasmic membrane decrease until both reach a constant level.
Verwendete Abkürzungen BChl. Bacteriochlorophyll 相似文献
4.
In contrast to the inhibition by gentamicin of glucose production from propionate, pyruvate and lactate in renal tubules incubated at 2.5 mM Ca2+, this antibiotic does not affect gluconeogenesis from propionate and lactate, and significantly stimulates this process from other substrates at 0.5 mM Ca2+. This may be due to the gentamicin-induced increase of the cytosolic manganese content (from 1.7 to 2.7 nmol/mg protein), resulting in a stimulation of cytosolic phosphoenolpyruvate carboxykinase activity. At 2.5 mM Ca2+ the cytosolic Mn content (2.7 nmol/mg protein) seems to be high enough to accomplish activation of the enzyme. 相似文献
5.
6.
Enzyme production in a cell recycle fermentation system was studied by computer simulations, using a mathematical model of -amylase production by Bacillus amyloliquefaciens. The model was modified so as to enable simulation of enzyme production by hypothetical organisms having different production kinetics at different fermentation conditions important for growth and production. The simulations were designed as a two-level factorial assay, the factor studied being fermentation with or without cell recycling, repression of product synthesis by glucose, kinetic production constants, product degradation by a protease, mode of fermentation, and starch versus glucose as the substrate carbon source.The main factor of importance for ensuring high enzyme production was cell recycling. Product formation kinetics related to the stationary growth phase combined with continuous fermentation with cell recycling also had a positive impact. The effect was greatest when two or more of these three factors were present in combinations, none of them alone guaranteeing a good result. Product degradation by a protease decreased the amount of product obtained; however, when combined with cell recycling, the protease effect was overshadowed by the increased production. Simulation of this type should prove a useful tool for analyzing troublesome fermentations and for identifying production organisms for further study in integrated fermentation systems.List of Symbols
a
proportionality constant relating the specific growth rate to the logarithm of G (h)
-
a
1
reaction order with respect to starch concentration
-
a
2
reaction order with respect to glucose concentration
-
c
starch concentration (g/l)
-
c
0
starch concentration in the feed (g/l)
-
D
dilution rate (h–1)
-
e
intrinsic intracellular amylase concentration (g product/g cell mass)
-
E
extracellular amylase concentration (g/l)
-
F
volumetric flow rate (l/h)
-
G
average number of genome equivalents of DNA/cell
-
K
1
intracellular repression constant
-
K
2
intracellular repression constant
-
K
s
Monod saturation constant (g/l)
-
k
3
product excretion rate constant (h–1)
-
k
I
translation constant (g product/g mRNA/h)
-
k
d
first order decay constant (h–1)
-
k
dw
first order decay constant (h–1)
-
k
gl
rate constant for glucose production (g/l/h)
-
k
m, dgr
saturation constant for product degradation (g/l)
-
k
st
rate constant for starch hydrolysis (g/l/h)
-
k
t1
proportionality constant for amylase production (g mRNA/g substrate)
-
k
t2
proportionality constant for amylase production (g mRNA *h/g substrate)
-
k
w
protease excretion rate constant (h–1)
-
k
wt1
proportionality constant for protease production (g mRNA/g substrate)
-
k
wt2
proportionality constant for protease production (g mRNA *h/g substrate)
-
k
wI
translation constant (g protease/g mRNA/h)
-
m
maintenance coefficient (g substrate/g cell mass/h)
-
n
number of binding sites for the co-repressor on the cytoplasmic repressor
-
Q
repression function, K1/K2 less than or equal to 1.0
-
Q
w
repression function, K1/K2 less than or equal to 1.0
-
r
intrinsic amylase mRNA concentration (g mRNA/g cell mass)
-
r
m
intrinsic protease mRNA concentration (g mRNA/g cell mass)
-
R
ex
retention by the filter of the compounds x=: C starch, E amylase, or S glucose
-
R
t
amylase transport rate (g product/g cell mass/h)
-
R
wt
protease transport rate (g protease/g cell mass/h)
-
R
s
rate of glucose production (g/l/h)
-
R
c
rate of starch hydrolysis (g/l/h)
-
S
0
feed concentration of free reducing sugar (g/l)
-
s
extracellular concentration of reducing sugar (g/l)
-
t
time (h)
-
V
volume (1)
-
w
intracellular protease concentration (g/l)
-
W
extracellular protease concentration (g/l)
-
X
cell mass concentration (dry weight) (g/l)
-
Y
yield coefficient (g cell mass/g substrate)
-
substrate uptake (g substrate/g cell mass/h)
-
specific growth rate of cell mass (h–1)
-
d
specific death rate of cells (h–1)
-
m
maximum specific growth rate of cell mass (h–1)
-
m,dgr
maximum specific rate of amylase degradation (h–1)
This study was supported by the Nordic Industrial Foundation Bioprocess Engineering Programme and the Center for Process Biotechnology, The Technical University of Denmark. 相似文献
7.
Jörg Müller Oliver Mitesser Marc W. Cadotte Fons van der Plas Akira S. Mori Christian Ammer Anne Chao Michael Scherer-Lorenzen Petr Baldrian Claus Bässler Peter Biedermann Simone Cesarz Alice Claßen Benjamin M. Delory Heike Feldhaar Andreas Fichtner Torsten Hothorn Claudia Kuenzer Marcell K. Peters Kerstin Pierick Thomas Schmitt Bernhard Schuldt Dominik Seidel Diana Six Ingolf Steffan-Dewenter Simon Thorn Goddert von Oheimb Martin Wegmann Wolfgang W. Weisser Nico Eisenhauer 《Global Change Biology》2023,29(6):1437-1450
Intensification of land use by humans has led to a homogenization of landscapes and decreasing resilience of ecosystems globally due to a loss of biodiversity, including the majority of forests. Biodiversity–ecosystem functioning (BEF) research has provided compelling evidence for a positive effect of biodiversity on ecosystem functions and services at the local (α-diversity) scale, but we largely lack empirical evidence on how the loss of between-patch β-diversity affects biodiversity and multifunctionality at the landscape scale (γ-diversity). Here, we present a novel concept and experimental framework for elucidating BEF patterns at α-, β-, and γ-scales in real landscapes at a forest management-relevant scale. We examine this framework using 22 temperate broadleaf production forests, dominated by Fagus sylvatica. In 11 of these forests, we manipulated the structure between forest patches by increasing variation in canopy cover and deadwood. We hypothesized that an increase in landscape heterogeneity would enhance the β-diversity of different trophic levels, as well as the β-functionality of various ecosystem functions. We will develop a new statistical framework for BEF studies extending across scales and incorporating biodiversity measures from taxonomic to functional to phylogenetic diversity using Hill numbers. We will further expand the Hill number concept to multifunctionality allowing the decomposition of γ-multifunctionality into α- and β-components. Combining this analytic framework with our experimental data will allow us to test how an increase in between patch heterogeneity affects biodiversity and multifunctionality across spatial scales and trophic levels to help inform and improve forest resilience under climate change. Such an integrative concept for biodiversity and functionality, including spatial scales and multiple aspects of diversity and multifunctionality as well as physical and environmental structure in forests, will go far beyond the current widely applied approach in forestry to increase resilience of future forests through the manipulation of tree species composition. 相似文献
8.
Nb1-particles fromNitrobacter agilis were found to be highly stable and could only be disrupted by chemicals or prolonged sonication.Spectra of the Nb1-particles indicated that protein is their major component. They contain no lipid.Highly purified Nb1-particles that were electronmicroscopically free from contaminating membranes, contained 7 different proteins, as shown by sodium dodecyl sulfate-polyacrylamide gelelectrophoresis.Abbreviations SDS
sodium dodecyl sulfate
- PAGE
polyacrylamide-gelelectrophoresis
- M. W.
molecular weight
- O.D.
opitical density
- HAA
hepatitis associated antigen 相似文献
9.
Patch occupancy of two hemipterans sharing a common host plant 总被引:5,自引:0,他引:5
Robert Biedermann 《Journal of Biogeography》2004,31(7):1179-1184
Aim Two hemipteran species were chosen as a study system for the comparative analysis of patch occupancy and spatial population structure of insects sharing a common host plant. This study tested whether (1) the incidence in the host plant patches differed between the two species, and (2) the two species exhibited a different spatial population structure, i.e. were they affected differentially by isolation and area of the host plant patches. Location The porphyry landscape north of Halle (Saale) in Germany comprising 506 patches of the host plant Brachypodium pinnatum. Methods The host plant patches were surveyed for the two hemipterans. To assess the influence of patch quality on species occurrence the patches were characterized by mean cover abundance of B. pinnatum, type of subsoil, slope, exposure, and shading. The spatial configuration of the patches was considered by patch area and isolation. The influence of the habitat factors and the spatial configuration on the occupancy of the two species was analysed by logistic regression. Results Adarrus multinotatus was found in 441 patches, while Neophilaenus albipennis was found in only 90 patches. While A. multinotatus showed virtually no relationship to the habitat factors, the occupancy of N. albipennis was influenced by subsoil type, cover abundance, and shading. The effects of area and isolation on occupancy of the patches also differed between the two species. The occupancy of N. albipennis was determined largely by area and isolation, whereas in A. multinotatus no considerable effect of spatial configuration was found. Main conclusions The study revealed a marked difference between the two hemipteran species in respect of spatial population structure. Adarrus multinotatus built up a ‘patchy population’, whereas N. albipennis showed a ‘metapopulation’ structure within the same set of patches in the same landscape. Spatial population structure was found to be not only a function of spatial configuration of habitat patches, but population structure differed between the habitat generalist A. multinotatus and the habitat specialist N. albipennis. 相似文献
10.
Anaerobic Co-Culture of Mesenchymal Stem Cells and Anaerobic Pathogens - A New In Vitro Model System