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1.
Umbelopsis gibberispora is described as a new species in the genus Umbelopsis, Umbelopsidaceae, Mucorales. The species differs from others in this genus by ellipsoidal sporangiospores with unilaterally
thickened walls. Phylogenetic analyses based on nuclear large subunit ribosomal DNA (nLSU rDNA) partial sequences suggest
that U. gibberispora, U. swartii, and U. westeae form a clade together with the strains of Umbelopsis ramanniana. The ex-type strain of Micromucor ramannianus var. angulisporus is found to be very close to Umbelopsis vinacea, whereas other isolates identified under the former name in the sense of Linnemann fall in the U. ramanniana subclade. For these isolates, a new species, Umbelopsis angularis, is introduced. Phylogenetic relationships among Umbelopsis species are discussed related to their attributes of the sporangial wall and mature spore shapes.
Received: August 27, 2002 / Accepted: March 11, 2003
Acknowledgments We thank Dr. Takashi Ohsono, Graduate School of Agriculture, Kyoto University, Japan, for providing the strain of U. gibberispora (CBS 109328). We also thank Dr. Wieland Meyer, University of Sydney, Australia for access to the phylogenetic tree based
on ITS sequence data before publishing, and Dr. Richard C. Summerbell, Centraalbureau von Schimmelcultures, the Netherlands,
for linguistic corrections. 相似文献
2.
Two Exobasidium species causing Exobasidium leaf blister on Rhododendron spp. are described. An Exobasidium leaf blister on Rhododendron yedoense var. yedoense f. yedoense has been recognized in Hokkaido Prefecture, Japan, since the first report was issued in 1950. The causal fungus is identified
with Exobasidium dubium from the morphology of its hymenial structure and mode of germination of the basidiospores. Another Exobasidium leaf blister
on Rhododendron dauricum has been observed in Hokkaido Prefecture, Japan. In comparison with morphology based on hymenial structure and mode of germination
of the basidiospores of the 100 validly described taxa, this fungus differs from those known taxa in the size of basidia and
basidiospores, the numbers of sterigmata and septa of basidiospores, and the mode of germination of basidiospores. Thus, a
new species, Exobasidium miyabei, is established and illustrated.
Received: February 13, 2002 / Accepted: September 25, 2002
Present address: National Institute of Agrobiological Sciences, Tsukuba 305-8602, Japan
Acknowledgments We profoundly appreciate the cooperation of Dr. V. Melnik in providing Russian papers and Dr. L. Vasilyeva for translating
them into English. We thank Prof. H. Takahashi for loaning the materials in the Herbarium of the Hokkaido University Museum
and Dr. W. Abe, Graduate School of Science, University of Hokkaido, for his kind help with the sampling of R. dauricum in Teshikaga, Hokkaido Prefecture. This study was supported in part by a Grant-in-Aid for Scientific Research (B) (No. 13460019),
Japan Society for the Promotion of Science (JSPS).
Contribution No. 171, Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of Tsukuba.
Correspondence to:M. Kakishima 相似文献
3.
Lindström T 《Journal of mathematical biology》2002,45(5):396-418
In this paper we derive and analyze a discrete version of Rosenzweig's (Am. Nat. 1973) food-chain model. We provide substantial
analytical and numerical evidence for the general dynamical patterns of food chains predicted by De Feo and Rinaldi (Am. Nat.
1997) remaining largely unaffected by this discretization. Our theoretical analysis gives rise to a classification of the
parameter space into various regions describing distinct governing dynamical behaviors. Predator abundance has a local optimum
at the edge of chaos.
Received: 13 August 1999 / Revised version: 12 March 2002 / Published online: 17 October 2002
Mathematics Subject Classification (1991): 92D40
Keywords or phrases: Discrete food-chain – Discrete Hopf (Neimark-Sacker) bifurcation – Pulsewise birth processes – Mean yield maximization –
Nicholson-Bailey model 相似文献
4.
Summary. Ratiometric fluorescent dyes are often used to monitor free ion concentrations in vivo, especially in cells that are recalcitrant
to transformation with genetically encoded fluorescent markers. Although intracellular dye distributions are often found to
be cytosolic, dye localisation has often not been examined in detail. We began exploring the use of BCECF (2′,7′-bis(2-carboxyethyl)-5(6)-carboxyfluorescein)
to monitor pH in the giant alga Chara australis and discovered that younger leaf cells could be loaded using the acetoxymethyl ester of BCECF. However, we were puzzled to
find in microphotometric measurements that the fluorescence ratio appeared insensitive to manipulations affecting cytosolic
pH. Confocal imaging of C. australis cells loaded with BCECF showed an accumulation of the dye in two locations: (1) on the outside of the chloroplasts in irregularly
shaped stationary bodies; (2) within 1–1.5 μm structures that moved rapidly with the pericellular cytoplasmic streaming. Together
with the streaming cytoplasm, these organelles were rendered stationary with 50 μM cytochalasin D. Rhodamine 123, a mitochondrionspecific
dye, highlighted organelles outside of the chloroplasts, similar to those shown by BCECF in location 1. We conclude that in
the cytoplasmic compartment, BCECF was sequestered within cytoplasmic mitochondria in immature and fast-growing cells and
within the cortical mitochondrial system in older and slowly growing cells. Thus, BCECF-AM is unsuitable for reporting changes
in cytosolic pH in C. australis but might be employed in future to study pH changes in the mitochondria.
Correspondence: M. J. Beilby, Biophysics, School of Physics, University of New South Wales, Sydney 2052, Australia. 相似文献
5.
We describe a neural network that enhances and completes salient closed contours in images. Our work is different from all
previous work in three important ways. First, like the input provided to primary visual cortex (V1) by the lateral geniculate
nucleus (LGN), the input to our computation is isotropic. That is, it is composed of spots, not edges. Second, our network
computes a well-defined function of the input based on a distribution of closed contours characterized by a random process.
Third, even though our computation is implemented in a discrete network, its output is invariant to continuous rotations and
translations of the input image.
Received: 11 July 2002 / Accepted in revised form: 25 October 2002
Acknowledgements. L.R.W. was supported in part by Los Alamos National Laboratory. J.W.Z. was supported in part by the Albuquerque High Performance
Computing Center. We wish to thank Jonas August and Steve Zucker for their insightful comments.
Correspondence to: L.R. Williams (e-mail: Williams@cs.unm.edu) 相似文献
6.
We extend the analysis of simple, energy-conserving models for the dynamics of insect locomotion in the horizontal plane
developed in Schmitt and Holmes (2000a,b, 2001), where gaits characteristic of steady cockroach running and turning were evoked.
In this paper, we include dissipation and energy inputs via active “muscles” in three forms: via prescribed torques at the
“hip” pivot, via an active spring element of variable length, and via a pair of Hill-type muscle models representing an extensor/flexor
system. Due to mechanical feedback of passive elastic forces, the stable gaits of the conservative models are preserved, and
now energy input and absorption balances to additionally stabilize a preferred speed, with only modest neural sensing and
feedback being required. However, these bipedal models still cannot simultaneously match observed moment-yaw magnitudes and
fore-aft dynamics.
Received: 17 September 2001 / Accepted: 20 February 2003 /
Published online: 20 May 2003
Correspondence to: P. Holmes (e-mail: pholmes@math.Princeton.EDU)
Acknowledgements. This work was supported by DARPA/ONR: N00014-98-1-0747 and DoE: DE-FG02-95ER25238. John Schmitt was partially supported by
a DoD Graduate Fellowship, a Wu Fellowship of the School of Engineering and Applied Science, and a George Van Ness Lothrop
Honorific Fellowship of the Graduate School at Princeton University. We thank Kenneth Meijer for allowing us to use his muscle
model in Sect. 4 and Bob Full and Dan Koditschek for numerous helpful suggestions. 相似文献
7.
Summary. Eight analogs 4a-7a and 4b-7b of philanthotoxin (PhTX) from wasp venom and nephilatoxin-8 (NPTX-8) from spider venom whose tyrosine or asparagine linker
is replaced by squaryl (sq) amino acid or 4-amino squaryl (4-asq) amino acid have been synthesized in an efficient manner
via coupling of N-acyl squaryl amino acid intermediate 19 or 26 with the corresponding polyamine part. Preliminary bioassay using crickets revealed that the analogs substituted by glutamate-type
squaryl amino acid-containing NPTX 7a and 7b showed more potent paralytic activities than that of NPTX-8.
Received April 25, 2002 Accepted June 21, 2002 Published online December 18, 2002
Acknowledgement This work was supported by a grant from Research for the Future Program from the Japan Society for the Promotion of Science
(JSPS).
Authors' address: Yasufumi Ohfune, Graduate School of Science, Osaka City University, Sugimoto, Osaka 558-8585, Japan, Fax: +81-6-6605-3153,
E-mail: ohfune@sci.osaka-cu.ac.jp 相似文献
8.
We establish the existence of traveling front solutions and small amplitude traveling wave train solutions for a reaction-diffusion
system based on a predator-prey model with Holling type-II functional response. The traveling front solutions are equivalent
to heteroclinic orbits in R
4
and the small amplitude traveling wave train solutions are equivalent to small amplitude periodic orbits in R
4
. The methods used to prove the results are the shooting argument and the Hopf bifurcation theorem.
Received: 25 May 2001 / Revised version: 5 August 2002 / Published online: 19 November 2002
RID="*"
ID="*" Research was supported by the National Natural Science Foundations (NNSF) of China.
RID="*"
ID="*" Research was partially supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada. On leave
from the Department of Mathematics and Statistics, Dalhousie University, Halifax, Nova Scotia B3H 3J5, Canada.
Mathematics Subject Classification (2000): 34C35, 35K57
Key words or phrases: Traveling wave solution – Wazewski set – Shooting argument – Hopf bifurcation
Acknowledgements. We would like to thank the two referees for their careful reading and helpful comments. 相似文献
9.
10.
11.
Dietary taurine enhances cholesterol degradation and reduces serum and liver cholesterol concentrations in rats fed a high-cholesterol diet 总被引:1,自引:0,他引:1
Summary. The effect of taurine on hypercholesterolemia induced by feeding a high-cholesterol (HC) diet (10 g/kg) to rats was examined.
When taurine was supplemented to HC for 2 wk, serum total cholesterol significantly decreased and serum HDL-cholesterol increased
compared with the HC diet group. In the hypercholesterolemic rats fed the HC diet, the excretion of fecal bile acids and hepatic
cholesterol 7α-hydroxylase (CYP7A1) activity and its mRNA level increased significantly, and the supplementation of taurine further enhanced
these indexes, indicating an increase in cholesterol degradation. Agarose gel electrophoresis revealed that, in hypercholesterolemic
rats fed the HC diet, the serum level of the heavier VLDL increased significantly, but taurine repressed this increase and
normalized this pattern. Significant correlations were observed between the time-dependent increase of CYP7A1 gene expression
and the decrease of blood cholesterol concentration in rats fed the HC diet supplemented with taurine. These results suggest
that the hypocholesterolemic effects of taurine observed in the hypocholesterolemic rats fed the HC diet were mainly due to
the enhancement of cholesterol degradation and the excretion of bile acid.
Received December 4, 2001 Accepted January 2, 2002 Published online September 10, 2002
Acknowledgment This work was supported by a grant of Taisho Pharmaceutical Co., Ltd (Japan). We thank J. I. Gordon for their generous gifts
of cDNAs.
Authors' address: Dr. Hidehiko Yokogoshi, School of Food and Nutritional Sciences, The University of Shizuoka, Shizuoka 4228526, Japan, E-mail:
yokogosi@u-shizuoka-ken.ac.jp 相似文献
12.
《Biotechnic & histochemistry》2013,88(3):193-194
OfficersPresident, H. J. Conn, Box 269, Geneva, N. Y. (representing Society of American Bacteriologists.)Vice-President, W. F. Windle, University of Pennsylvania, Philadelphia, Pa. Secretary, S. I. Kornhauser, University of Louisville Medical School, LouisvilleKy. Treasurer, E. H. Stotz, University of Rochester, School of Medicine, RochesterN. Y. (representing American Chemical Society.) 相似文献
13.
Exact formulas for the mean and variance of the proportion of different types in a fixed generation of a multi-type Galton-Watson
process are derived. The formulas are given in terms of iterates of the probability generating function of the offspring distribution.
It is also shown that the sequence of types backwards from a randomly sampled particle in a fixed generation is a non-homogeneous
Markov chain where the transition probabilities can be given explicitly, again in terms of probability generating functions.
Two biological applications are considered: mutations in mitochondrial DNA and the polymerase chain reaction.
Received: 10 June 2001 / Revised version: 21 November 2001 / Published online: 23 August 2002
Mathematics Subject Classification (2000): Primary 60J80, Secondary 92D10, 92D25
Key words or phrases: Multi-type Galton-Watson process – sampling formula – PCR – mitochondrial DNA 相似文献
14.
The trophic interaction in the pelagic food web of oligotrophic-dystrophic Lake Shirakoma-ike was investigated by a stable
isotope technique. Carbon and nitrogen isotope analyses revealed the trophic interaction among Piona carnea (a water mite), Chaoborus sp. (a phantom midge), Daphnia longispina (a cladoceran), and Acanthodiaptomus pacificus (a calanoida copepoda). The δ13C values for estimating the relative contributions of D. longispina and A. pacificus to carnivores were used, and they were also used for the constraint of the trophic enrichment factor of δ15N. Both Chaoborus sp. and P. carnea were suggested to consume D. longispina and A. pacificus at almost the same ratio (1 : 1). However, both carnivores preferred A. pacificus to D. longispina, because D. longispina was much more abundant in the lake than A. pacificus. Omnivory of P. carnea was also analyzed by the mixing model.
Received: February 28, 2002 / Accepted: July 10, 2002
Present address: Hydrospheric Atmospheric Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan Tel. +81-52-789-3434;
Fax +81-52-789-3436 e-mail: lee@ihas.nagoya-u.ac.jp
Present address: Research Institute for Humanity and Nauture, Kyoto, Japan
Acknowledgments We would like to thank Professor Kikuo Kato for providing useful comments and colleagues in the Laboratory of Biogeochemical
Data Analysis, Nagoya University, for their support with the sample collection. We are in debt to Dr. R. Coucett for the kind
suggestion on the trophic enrichment factors for blood-sucking insects. We also thank the members of the Suwa Hydrobiological
Station, Shinshu University, who kindly allowed us to use facilities for sampling in Lake Shirakoma-ike. The zooplankton samples
were partly provided by Mr. Masataka Yoshida.
Correspondence to:J.-Y. Lee 相似文献
15.
The diversity of ericoid mycorrhizal fungi of Rhododendron obtusum var. kaempferi was examined in a stand of Pinus densiflora at Tsukuba, Japan. In total, 153 slow-growing fungal isolates were obtained from roots of R. obtusum var. kaempferi, in which 113 isolates formed an ericoid mycorrhizal structure in vitro. Among them, 53 isolates were morphologically identified
as Oidiodendron maius, but the others were not identified due to their sterilities. PCR-RFLP analysis in the rDNA-ITS region divided them into
four different RFLP types. Phylogenetic analysis from sequence data of the region suggested that the four RFLP types belonging
to distinct taxa and one sterile type are considered to be Hymenoscyphus ericae. This study is the first report of ericoid mycorrhizal fungi in a natural habitat in Japan.
Received: August 23, 2002 / Accepted: December 11, 2002
Acknowledgments We thank Dr. K. Narisawa, Plant Biotechnology Institute, Ibaraki Agricultural Center, and Dr. R.S. Currah, Department of
Biological Science, University of Alberta, for their helpful advice.
Contribution no. 176, Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of Tsukuba,
Japan
Correspondence to:M. Kakishima 相似文献
16.
Lee Xenakis Blonder 《Human nature (Hawthorne, N.Y.)》1991,2(2):83-116
American anthropology is distinguished by a four-fields approach in which biological, cultural, archaeological, and linguistic
dimensions of behavior are examined in evolutionary and cross-cultural perspective. Nevertheless, assumptions of mind-body
dualism pervade scholarly thinking in anthropology and have prevented the development of a truly integrated science of human
experience. This dualism is most exemplified by the lack of consideration of the role of the brain in both “physical” and
“mental” processes, including phenomena labeled as cultural. In this paper, I review neural mechanisms of learning, communication,
and emotion, and discuss the implications of these findings for culture theory.
Lee Xenakis Blonder is an assistant professor in the Department of Behavioral Science and the Sanders-Brown Center on Aging,
University of Kentucky Medical School, Lexington. She is currently examining the effects of stroke in different regions of
the brain on language, nonverbal communication, and emotional processing in an attempt to better understand human brain and
behavior relations. Recent publications include “Neuropsychological Functioning in Hemiparkinsonism” (with R. E. Gur, R. C.
Gur, A. J. Saykin, and H. I. Hurtig),Brain and Cognition 9:244–257 (1989). 相似文献
17.
We studied the correlation between pathogenicity and restriction fragment length polymorphism (RFLP) type, which was determined
by polymerase chain reaction-based RFLP analysis of the internal transcribed spacer regions of ribosomal DNA, in the willow
leaf rust fungi Melampsora epitea and M. humilis. Eighteen clones of eight Salix species were inoculated with urediniospores from seven collections of the two rust species. M. epitea and M. humilis (RFLP type-5 collections) were pathogenic to six to eight Salix species. RFLP type-7 collections of M. epitea were pathogenic to only two Salix species. The taxonomic relationships of the two rust species are discussed.
Received: December 11, 2002 / Accepted: February 17, 2003
RID="*"
ID="*" Contribution no. 179, Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of
Tsukuba, Japan
Acknowledgments We thank K. Katsuya, former professor at the University of Tsukuba, for his encouragement in this study. We are also grateful
to M. Yashima, Botanical Garden, University of Tohoku, for his assistance in collecting materials and to R. Suzuki, University
of Tsukuba, for providing a rust isolate. 相似文献
18.
Rolando Brawer Facundo D. Batista Oscar R. Burrone Daniel O. Sordelli M. C. Cerquetti 《Archives of microbiology》1998,169(6):530-533
A temperature-sensitive mutant of Salmonella typhimurium was isolated earlier after transposon mutagenesis with Tn10d Tet. The mutant D220 grows well at 28 °C but has a lower growth rate and forms filaments at 37 °C. Transposon-flanking fragments
of mutant D220 DNA were cloned and sequenced. The transposon was inserted in the dam gene between positions 803 and 804 (assigned allele number: dam-231 : : Tn10d Tet) and resulted in a predicted ten-amino-acid-shorter Dam protein. The insertion created a stop codon that led to a truncated
Dam protein with a temperature-sensitive phenotype. The insertion dam-231 : : Tn10d Tet resulted in a dam“leaky” phenotype since methylated and unmethylated adenines in GATC sequences were present. In addition, the dam-231 : : Tn10d Tet insertion rendered dam mutants temperature-sensitive for growth depending upon the genetic background of the S. typhimurium strain. The wild-type dam gene of S. typhimurium exhibited 82% identity with the Escherichia coli dam gene. 相似文献
19.
We introduce inhomogeneous, substrate dependent cell division in a time discrete, nonlinear matrix model of size-structured
population growth in the chemostat, first introduced by Gage et al. [8] and later analysed by Smith [13]. We show that mass conservation is verified, and conclude that our system admits one
non zero globally stable equilibrium, which we express explicitly. Then we run numerical simulations of the system, and compare
the predictions of the model to data related to phytoplankton growth, whose obtention we discuss. We end with the identification
of several parameters of the system.
Received: 9 February 2000 / Revised version: 10 October 2001 / Published online: 23 August 2002
RID="*"
ID="*" Present address: Department of Mathematics and Statistics, University of Victoria, B.C., Canada. e-mail: jarino@math.uvic.ca
Key words or phrases: Chemostat – Structured population models – Discrete model – Inhomogeneous division size 相似文献
20.
Schliekelman P 《Journal of mathematical biology》2003,46(2):171-188
With recent advances in molecular genetics, it is likely that releases of genetically modified organisms will be used for
a variety of purposes. In many cases, such systems would utilize organisms that have been modified on multiple genetic loci.
Predicting the effect of such releases will require an understanding of the transient dynamics in the system. However, theoretical
understanding of transient dynamics in multilocus systems is limited, particularly for early generations when gametic disequilibrium
is still high. I derive approximate expressions for marginal allele frequency and marginal two-locus disequilibrium that are
applicable in this initial period, assuming infinite population size, two alleles per locus, and weak viability selection.
I then apply these results to exploring the effect of parameters on the frequency of the resident gamete type in a release
of organisms carrying an autocidal allele on multiple loci. This leads to simple approximate expressions for the optimal number
of loci carrying the autocidal allele (as a function of release size and the degree of natural selection against the alleles)
and the size of release needed to overcome a given level of selection against the released alleles.
Received: 5 March 2001 / Revised version: 10 July 2002 / Published online: 18 December 2002
Current address: Department of Statistics, 204 Statistics Building, University of Georgia, Athens, GA 30602-1952, USA. e-mail:
pdschlie@stat.uga.edu
Key words or phrases: Multilocus – Selection – Transgenic – Pest control – Genetic control
Acknowledgements. I thank Steve Ellner for insight and guidance throughout this project. This research was partially funded by a fellowship
from the College of Agricultural and Life Sciences Foundation of North Carolina State University. 相似文献