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1.
Damian O. Elias Bruce R. Land Andrew C. Mason Ronald R. Hoy 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2006,192(8):799-800
Animals emit visual signals that involve simultaneous, sequential movements of appendages that unfold with varying dynamics in time and space. Algorithms have been recently reported (e.g. Peters et al. in Anim Behav 64:131–146, 2002) that enable quantitative characterization of movements as optical flow patterns. For decades, acoustical signals have been rendered by techniques that decompose sound into amplitude, time, and spectral components. Using an optic-flow algorithm we examined visual courtship behaviours of jumping spiders and depict their complex visual signals as “speed waveform”, “speed surface”, and “speed waterfall” plots analogous to acoustic waveforms, spectrograms, and waterfall plots, respectively. In addition, these “speed profiles” are compatible with analytical techniques developed for auditory analysis. Using examples from the jumping spider Habronattus pugillis we show that we can statistically differentiate displays of different “sky island” populations supporting previous work on diversification. We also examined visual displays from the jumping spider Habronattus dossenus and show that distinct seismic components of vibratory displays are produced concurrently with statistically distinct motion signals. Given that dynamic visual signals are common, from insects to birds to mammals, we propose that optical-flow algorithms and the analyses described here will be useful for many researchers.Damian O. Elias and Bruce R. Land contributed equallyAn erratum to this article can be found at 相似文献
2.
Agonistic behavior was studied longitudinally for 16 months in an intact family groups of captive emperor tamarins (Saguinus
imperator subgrisescens) using methods from quantitative ethology and social network analysis. A motivational analysis of
the components of agonistic display revealed the relative strength of each component along a continuum from strongly dominant
to strongly subordinate. Tabulations of exchanges of strongly dominant and strongly subordinate components in interactions
among the tamarins revealed an agonistic network (“dominance hierarchy”) that approached, but did not quite reach, the ideal
state of a transitive order (“linear dominance hierarchy”). The frequency with which individual tamarins long called and scent
marked was not closely correlated with their position (“dominance rank”) in the agonistic network. Instead, individuals undergoing
change in status long called and scent marked frequently, irrespective of their rank. 相似文献
3.
I. N. Konareva 《Neurophysiology》2006,38(3):201-208
Modifications of different EEG rhythms induced by a single neurofeedback session (by the EEG characteristics) directed toward
an increase in the ratio of the spectral powers (SPs) of the α vs θ oscillations were compared with the psychological characteristics of the tested subjects (the group included 30 persons).
A generally accepted neurofeedback technique was used; the intensity of acoustic white noise served as the feedback signal.
EEG potentials were recorded from the C3 and C4 leads. Psychological testing was carried out using Eysenck’s (EPQ), Rusalov’s
(OST), and (16 PF) questionnaires. The directions of changes in the SPs of EEG frequency components were found to significantly
correlate with some individuality-related peculiarities of the tested subjects. The SP of the δ rhythm correlated with the
EPQ scale “neuroticism,” OST scale “social plasticity,” and 16 PF factors H (“parmia”), I (“premsia”), and Q3 (“self-control of behavior”). The SP of the θ component demonstrated correlations with the OST scales “ergisity,” “plasticity,”
and “social temp” and with 16 PF factors M (“autia”), Q4 (“frustration”), and Q1 (“exvia”). The SP of the α rhythm correlated with 16 PF factors Q3 (“self-control of behavior”), G (“strength of superEgo”), O (“hypothymia”), L (“protension”), and N (“shrewdness”). The SP
of the β rhythm correlated with the OST scale “emotionality,” while that of the γ rhythm showed correlations with the 16 PF
indices L (“protension”) and M (“autia”). Changes in the ratio of the α vs θ SPs correlated with the EPQ scale “neuroticism.” Thus, our data confirm the statement that a high individual variability
of the results of a single (first in the series) neurofeedback session is to a great extent related to peculiarities of the
individual psychological pattern of the subject.
Neirofiziologiya/Neurophysiology, Vol. 38, No. 3, pp. 239–247, May–June, 2006. 相似文献
4.
Kenichi Ohara Momoko Hotta Daisuke Takahashi Takashi Asahida Hitoshi Ida Tetsuya Umino 《Ichthyological Research》2009,56(4):373-379
The genetic diversity and relationship among four morphotypes of Rhinogobius sp. OR, Gobiidae (“Tōshoku,” “Shinjiko,” “Gi-tōshoku,” and “Shimahire”) were investigated with seven microsatellite DNA loci,
and amphidromy of these morphotypes was verified by strontium (Sr) and calcium (Ca) deposition in the otolith. Samples of
“Tōshoku,” “Shinjiko,” “Gi-tōshoku,” and “Shimahire” were collected from, respectively, three, three, two, and four locations
in Japan. Microsatellite analysis detected high genetic diversity (based on the number of alleles, allelic richness, and average
observed heterozygosity) in the “Tōshoku” and “Shinjiko” morphotypes relative to the “Shimahire” morphotype; the “Gi-tōshoku”
morphotype had an intermediate level of variation. Almost all pairwise F
ST values were significantly different from zero (P < 0.001), except between two populations of “Tōshoku.” Clear genetic independence was observed between the “Shinjiko” and
“Shimahire” morphotypes in the Maruyama River. A principle component analysis based on microsatellite data indicated that
the “Tōshoku,” “Shinjiko,” and “Gi-tōshoku” morphotypes were genetically similar. Furthermore, the three populations of “Tōshoku”
were closely related each other, and two of those collected from the Lake Biwa system were a single population. There was,
however, a high degree of genetic differentiation between “Shimahire” and the other morphotypes; moreover, there was high
genetic divergence among four populations of the “Shimahire” morphotype. Amphidromous migratory histories were indicated by
Sr:Ca ratios in two of three populations of the “Shinjiko” morphotype and in one of two “Gi-tōshoku” morphotypes, whereas
all populations of the “Shimahire” morphotype were freshwater residents. The large genetic divergence and low genetic diversity
in “Shimahire” are likely related to migration history. 相似文献
5.
G. Meinhardt 《Biological cybernetics》2001,85(6):401-422
The detection of compound sinusoidal gratings of various spatial frequency separations and four different grating sizes has
been studied using the summation-to-threshold paradigm. Contrast interrelation functions have been measured and spatial frequency
tuning estimates, based on the slope of the contrast interrelation function at two definite points, were derived using the
“negative gradient technique” proposed by Logvinenko [Logvinenko (1995) Biol Cybern 73: 547–552]. It is shown that compound
grating detection can be modelled by assuming pattern-specific sensory mechanisms for each of the spatial frequency components,
which adapt to the periodicity and the size of the stimulus but not to its envelope function. Further, it is shown that relative
sensitivity for a given spatial frequency separation can be predicted with good accuracy by the correlation of the grating
components used for superposition. It is suggested that the most plausible implementation of the pattern correlation principle
in human grating detection is the “grating cell” model.
Received: 10 March 2000 / Accepted in revised form: 4 December 2000 相似文献
6.
J. B. Wickham J. M. M. Brown 《European journal of applied physiology and occupational physiology》1998,78(3):219-225
The aim of this investigation was to anatomically identify, and then determine the function of, individual segments within
the human deltoid muscle. The anatomical structure of the deltoid was determined through dissection and/or observation of
the shoulder girdles of 11 male cadavers (aged 65–84 years). These results indicate that the deltoid consists of seven anatomical
segments (D1–D7) based upon the distinctive arrangement of each segment's origin and insertion. Radiographic analysis of a
cadaveric shoulder joint suggested that only the postero-medial segment D7 has a line of action directed below the shoulder
joint's axis of rotation. The functional role of each individual segment was then determined utilising an electromyographic
(EMG) technique. Seven miniature (1 mm active plate; 7 mm interelectrode distance) bipolar surface electrodes were positioned
over the proximal portion of each segment's muscle belly in 18 male and female subjects (18–30 years). EMG waveforms were
then recorded during the production of rapid isometric shoulder abduction and adduction force impulses with the shoulder joint
in 40 degrees of abduction in the plane of the scapula. Each subject randomly performed 15 abduction and 15 adduction isometric
force impulses following a short familiarisation period. All subjects received visual feed back on the duration and amplitude
of each isometric force impulse produced via a visual force-time display which compared subject performance to a criterion
force-time curve. Movement time was 400 ms (time-to-peak isometric force) at an intensity level of 50% maximal voluntary contraction.
Temporal and intensity analyses of the EMG waveforms, as well as temporal analysis of the isometric force impulses, revealed
the neuromotor control strategies utilised by the CNS to control the activity of each muscle segment. The results showed that
segmental neuromotor control strategies differ across the breadth of the muscle and that individual segments of the deltoid
can be identified as having either “prime mover”, “synergist”, “stabiliser” or “antagonist” functions; functional classifications
normally associated with whole muscle function. Therefore, it was concluded that the CNS can “fine tune” the activity of at
least six discrete segments within the human deltoid muscle to efficiently meet the demands of the imposed motor task.
Accepted: 15 December 1997 相似文献
7.
The home range of resident animals is considered as “familiar area” including a “foraging area.” It has been revealed that
the activity of an average animal unit in the “foraging area” could be approximated by normal distribution. Estimation of
activity distribution in the “familiar area” (beyond the “foraging area”) was impeded by means of marking since it might be
difficult to record distant movements, and the method does not provide an essential body of data. In the case of the common
shrew Sorex araneus, the “familiar area” was estimated using pitfall as animals evade them in the known areal. The “foraging area” radius of
the average shrew was taken to be 30 m (95% of the animal unit activity), the radius of “familiar area” was within the range
of 180–240 m. The “foraging area” was expected to provide the animal with vital resources, and the “familiar area” reflects
its need for exploratory activity. 相似文献
8.
QTL analysis of fruit components in the progeny of a Rennell Island Tall coconut (Cocos nucifera L.) individual 总被引:2,自引:0,他引:2
Baudouin L Lebrun P Konan JL Ritter E Berger A Billotte N 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2006,112(2):258-268
We investigated the genetic factors controlling fruit components in coconut by performing QTL analyses for fruit component
weights and ratios in a segregating progeny of a Rennell Island Tall genotype. The underlying linkage map of this population
was already established in a previous study, as well as QTL analyses for fruit production, which were used to complement our
results. The addition of 53 new markers (mainly SSRs) led to minor amendments in the map. A total of 52 putative QTLs were
identified for the 11 traits under study. Thirty-four of them were grouped in six small clusters, which probably correspond
to single pleiotropic genes. Some additional QTLs located apart from these clusters also had relatively large effects on the
individual traits. The QTLs for fruit component weight, endosperm humidity and fruit production were found at different locations
in the genome, suggesting that efficient marker-assisted selection for yield can be achieved by selecting QTLs for the individual
components. The detected QTLs descend from a genotype belonging to the “Pacific” coconut group. Based on the known molecular
and phenotypic differences between “Pacific” and “Indo-Atlantic” coconuts, we suggest that a large fraction of coconut genetic
diversity is still to be investigated by studying populations derived from crosses between these groups.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
9.
Habitat fragmentation is a process involving splitting of continuous habitats into smaller, and more isolated habitat patches.
To assess the effects of small-scale habitat patchiness and isolation without the confounding effect of habitat loss on benthic
macrofauna, two field experiments were conducted in the Archipelago Sea, SW Finland. Using artificial seagrass units (ASUs)
we contrasted continuous patches (“C”) with fragmented patches (“F”) of the same combined area as the continuous patches.
The fragmentation treatment involved two isolation distances (0.5 and 3.0 m) between the ASUs (“F 0.5”) and (“F 3.0”). This
design was repeated in two consecutive experiments where the patch area was 0.25 and 0.0625 m2, respectively. Mobile epifauna were allowed to colonize patches for 12 days in both experiments. In both experiments, the
total epifaunal density was significantly higher in the “F 0.5” treatment than in the “C” treatment, and the three dominant
taxa showed positive or neutral responses to the habitat configuration. No fragmentation effect on the number of species was
detected in either of the experiments, but fragmentation had a negative effect on the epifaunal diversity (Shannon’s H′) in the experiment with the largest patch area. Epifaunal diversity was significantly lower in “F 3.0” treatment than in
“C” or “F 0.5” treatments in the first experiment, indicating stronger effect of isolation instead of fragmentation per se.
Edge effects were indirectly tested by comparing epifaunal densities with patch edge:area ratios. The results suggest that
edge effects may have a more important role than patch size for the total densities of epifaunal taxa, and that small, isolated
patches have equal or higher habitat value compared to larger fragments. 相似文献
10.
Shiow-Ing Wang Long-Teng Lee Ming-Lun Zou Chen-Wei Fan Chin-Liang Yaung 《Radiation and environmental biophysics》2010,49(1):57-65
The purpose of the study was to investigate whether proximity to nuclear power plants may increase the risk of abnormal pregnant
outcomes among the resident women. In this ecological study, data were used from the Health Services Birth Reports Database
established by the Bureau of Health Promotion, National Department of Health, Taiwan, in 2001–2004. Chi-square-tests were
carried out to investigate the “Plant-vicinity” and “Non plant-vicinity” group in terms of pregnancy outcome. Additionally,
logistic regression was performed to investigate whether residence in the vicinity of a nuclear power plant was related to
any abnormal pregnancy results. Based on data from 5,679 included subjects, no difference was observed between pregnancy outcomes
of the “Plant-vicinity” and “Non plant-vicinity” groups. After accounting for possible confounders, the adjusted odds ratios
were 1.20 (95% CI = 0.56–2.56) for stillbirth, 1.21 (95% CI = 0.95–1.53) for premature birth, 1.04 (95% CI = 0.79–1.37) for
low birth weight, and 1.58 (95% CI = 0.85–2.93) for congenital deficiencies, respectively, when comparing the “Plant-vicinity”
with the “Non plant-vicinity” group. The results of the study indicate that residence in the vicinity of a nuclear power plant
is not a significant factor which will cause abnormal health situations during pregnancy. 相似文献
11.
Yokoyama A Muneta T Nimura A Koga H Mochizuki T Hata Y Sekiya I 《Cell and tissue research》2007,329(3):469-478
Elastic cartilage-derived cells cultured two-dimensionally with FGF2 and corticosteroid produce gel-type masses that become
mature cartilage when injected into a subcutaneous pocket. This unique method has previously been clinically applied for treatments
of nasal augmentation. However, the components of the gel-type mass and the mechanism of its synthesis remain unknown. Here,
we have investigated the components of the gel-type mass produced by elastic cartilage-derived cells, and whether this gel-type
mass can be produced by using other cell sources or other media. Human elastic cartilage-derived cells from auricular cartilage,
hyaline cartilage-derived cells from articular cartilage, and mesenchymal stem cells from synovium were cultured in three
media: “redifferentiation medium” containing FGF2 and dexamethasone; “chondrogenic medium” containing bone morphogenetic protein-2,
transforming growth factor-β3, and dexamethasone specific for in vitro chondrogenesis of mesenchymal stem cells; control medium.
The elastic cartilage-derived cells cultured in redifferentiation medium produced a gelatinous matrix positive for Alcian
blue. During culture, the amount of chondroitin 4-sulfate, chondroitin 6-sulfate, and especially hyaluronan increased. However,
the expression of RNAs for most chondrogenic genes did not increase. We also reproduced cartilage tissue formation by the
injection of elastic cartilage-derived cells with the gelatinous mass into the subcutaneous space of the nude mouse. The synthesis
of gelatinous matrix in vitro and the formation of cartilage tissue in vivo could be obtained only for the combination of
elastic cartilage-derived cells with redifferentiation medium.
This study was supported in part by grants from the “Japan Society for the Promotion of Science (19591752)” and “Center of
Excellence Program for Frontier Research on Molecular Destruction and Reconstruction of Tooth and Bone in Tokyo Medical and
Dental University” to Takeshi Muneta, and the “Japan Society for the Promotion of Science (18591657)” to Ichiro Sekiya. 相似文献
12.
Through the use of principal components analysis of the correlation matrix between excentricity quotients of intra- and inter-individual
transitions between pairs of the 22 most frequent behaviour elements of male and female gelada baboons observed in captivity,
the total variance could be described in terms of a low number of causal factors. In intra-individual sequences the five factors
requested of the analysis explain 74 per cent of the total variance. The following intra-individual groupings were found:
(I) “autostimulation”, (II) “intensive social” versus “groom”, (III) “male sexual”, (IV) “attack” versus “sexual presentation”,
and (V) “greeting” versus “threat”. In inter-individual transitions, the five factors explain 68 per cent of the variance.
The following communicative sets were found: (1) “female-sexual releasing”, (2) “greeting and approaching releasing” versus
“groom releasing”, (3) “austostimulation releasing” versus “male-sexual releasing”, (4) “fight releasing”, and (5) “conflict”.
Mimetic induction of same acts or acts within one particular intra-individual set was frequent. 相似文献
13.
The notion of “pressure” as an evolutionary “force” that “causes” evolution is a pervasive linguistic feature of biology textbooks,
journal articles, and student explanatory discourse. We investigated the consequences of using a textbook and curriculum that
incorporate so-called force-talk. We examined the frequency with which biology majors spontaneously used notions of evolutionary
“pressures” in their explanations, students’ definitions and explanations of what they meant when they used pressures, and
the structure of explanatory models that incorporated evolutionary pressures and forces. We found that 12–20 percent of undergraduates
spontaneously used “pressures” and/or “forces” as explanatory factors but significantly more often in trait gain scenarios
than in trait loss scenarios. The majority of explanations using “force-talk” were characterized by faulty evolutionary reasoning.
We discuss the conceptual similarity between faulty notions of evolutionary pressures and linguists’ force-dynamic models
of everyday reasoning and ultimately question the appropriateness of force-talk in evolution education. 相似文献
14.
Morris H. Baslow 《Biosemiotics》2011,4(1):39-53
The human brain is a complex organ made up of neurons and several other cell types, and whose role is processing information
for use in elicitation of behaviors. To accomplish this, the brain requires large amounts of energy, and this energy is obtained
by the oxidation of glucose (Glc). However, the question of how the oxidation of Glc by individual neurons in brain results
in their collective ability to rapidly generate feats of cognition that allow them to recognize the nature of the universe
in which they live and to communicate this information remains unclear. In this article, insights into this process are provided
by first considering the brain’ s homeostatic “operating system” for supply of energy to stimulated neurons, and how this
system defines the basic unit of brain “structure”. This is followed by consideration of the brain’s “two-cell” neuronal communication
mechanism which defines the basic unit of brain “function”. Finally, an analysis of the nature of frequency-encoded “neuronal
languages” that enable ensembles of neurons to translate energy derived from the oxidation of Glc into a collective “mind”,
the aggregate of all brain processes including those involving perception, thought, insight, foresight, imagination and behavior. 相似文献
15.
G. B. Livshyts S. A. Kravchenko P. F. Tatarskyy I. A. Sudoma L. A. Livshits 《Cytology and Genetics》2008,42(4):272-277
The influence of FMR1, INHα1, NAT2, GSTT1 and GSTM1 genes mutations on ovarian function and their association with POF and “poor response” to exogenous GT after ovulation stimulation
were investigated. The carriers of Ala257Thr transition predominated in the studied “poor responders” group. In 1.6% POF patients
and 2.5% persons from “poor responders” group, but nobody from control group this transition combined with intermediate alleles
of FMR1 gene was observed. The frequency of deletion in GSTM1 gene in “poor responders” group was significantly higher (p = 0.01)
than in normal ovulatory control group. The frequency of Ser680Ser-Ala307Ala polymorphic genotype (22.2%) in “poor responders”
group was significantly higher (p = 0.028) than in normal-ovulatory control group (7.7%). The daily dosage of GT in intermediate
alleles of FMR1 gene carriers as well in patients with “slow acetylation” NAT2 genotype was significantly higher in comparison to patients without intermediate alleles and patients with “quick acetylation”
NAT2 genotype. Quantity of oocytes after stimulation ovulation in women with INHα1 gene Ala257Thr transition were significantly decreased in comparison to patients without such mutation. Further investigations
of these genes can play a major role in POF studying and modulation of ovarian response to exogenous GT.
Published in Ukrainian in Tsitologiya i Genetika, 2008, Vol. 42, No. 2, pp. 63–69.
The text was translated by the authors. 相似文献
16.
Chang-Gi Kim Dae In Kim Hyo-Jeong Kim Ji Eun Park Bumkyu Lee Kee Woong Park Soon-Chun Jeong Kyung Hwa Choi Joo Hee An Kang-Hyun Cho Young Soon Kim Hwan Mook Kim 《Journal of Plant Biology》2009,52(3):251-258
We conducted a 2-year field assessment of the gene flow from genetically modified (GM) chili pepper (Capsicum annuum L.), containing the PepEST (pepper esterase) gene, to a non-GM control line “WT512” and two commercial hybrid cultivars, “Manidda” and “Cheongpung Myeongwol
(CM).” After seeds were collected from the pollen-recipient non-GM plants, hybrids between them and the GM peppers were screened
by a hygromycin assay. PCR with the targeting hpt gene was performed to confirm the presence of transgenes in hygromycin-resistant seedlings. Out of 7,071 “WT512” seeds and
6,854 “Manidda” seeds collected in 2006, eight and 12 hybrids, respectively, were detected. In 2007, 33 hybrids from 3,456
“WT512” seeds and 50 hybrids from 3,457 “CM” seeds were found. The highest frequency of gene flow, 6.19%, was observed in
that 2007 trial. These results suggest that a limited isolation distance would be sufficient to prevent gene flow from GM
to conventionally bred chili peppers. 相似文献
17.
The sensory weighting model is a general model of sensory integration that consists of three processing layers. First, each
sensor provides the central nervous system (CNS) with information regarding a specific physical variable. Due to sensor dynamics,
this measure is only reliable for the frequency range over which the sensor is accurate. Therefore, we hypothesize that the
CNS improves on the reliability of the individual sensor outside this frequency range by using information from other sensors,
a process referred to as “frequency completion.” Frequency completion uses internal models of sensory dynamics. This “improved”
sensory signal is designated as the “sensory estimate” of the physical variable. Second, before being combined, information
with different physical meanings is first transformed into a common representation; sensory estimates are converted to intermediate
estimates. This conversion uses internal models of body dynamics and physical relationships. Third, several sensory systems
may provide information about the same physical variable (e.g., semicircular canals and vision both measure self-rotation).
Therefore, we hypothesize that the “central estimate” of a physical variable is computed as a weighted sum of all available
intermediate estimates of this physical variable, a process referred to as “multicue weighted averaging.” The resulting central
estimate is fed back to the first two layers. The sensory weighting model is applied to three-dimensional (3D) visual–vestibular
interactions and their associated eye movements and perceptual responses. The model inputs are 3D angular and translational
stimuli. The sensory inputs are the 3D sensory signals coming from the semicircular canals, otolith organs, and the visual
system. The angular and translational components of visual movement are assumed to be available as separate stimuli measured
by the visual system using retinal slip and image deformation. In addition, both tonic (“regular”) and phasic (“irregular”)
otolithic afferents are implemented. Whereas neither tonic nor phasic otolithic afferents distinguish gravity from linear
acceleration, the model uses tonic afferents to estimate gravity and phasic afferents to estimate linear acceleration. The
model outputs are the internal estimates of physical motion variables and 3D slow-phase eye movements. The model also includes
a smooth pursuit module. The model matches eye responses and perceptual effects measured during various motion paradigms in
darkness (e.g., centered and eccentric yaw rotation about an earth-vertical axis, yaw rotation about an earth-horizontal axis)
and with visual cues (e.g., stabilized visual stimulation or optokinetic stimulation).
Received: 20 September 2000 / Accepted in revised form: 28 September 2001 相似文献
18.
V. V. Shakhparonov 《Biology Bulletin》2011,38(5):528-532
The behavior of frogs from southern areas with an arid climate released during the reproductive period between their “home”
pond and a less distant river is shown to be independent of weather conditions. The experiments were performed on frogs living
near the village of Dosang, Astrakhan oblast. The frogs were released 60 to 150 m from their “home” breeding waterbody and
60 to 80 m from an “alien” waterbody. Four experiments were performed on 27 individuals. The movements of the frogs were traced
by the method of “tracking by a thread.” The results revealed no preference in the frogs to return to their own breeding ponds,
rather than to the nearby river. This behavior is peculiar to frogs of southern populations. 相似文献
19.
C. A. Abella X. P. Cristina A. Martinez I. Pibernat X. Vila 《Archives of microbiology》1998,169(5):452-459
Two new phototrophic consortia, “Chlorochromatium lunatum” and “Pelochromatium selenoides”, were observed and collected in the hypolimnion of several dimictic lakes in Wisconsin and Michigan (USA). The two consortia
had the same morphology but different pigment composition. The cells of the photosynthetic components of the consortia were
half-moon-shaped. This morphology was used to differentiate them from the previously described motile phototrophic consortia
“Chlorochromatium aggregatum” and “Pelochromatium roseum”. These phototrophic cells did not resemble any described unicellular green sulfur bacteria. The predominant pigments detected
were bacteriochlorophyll d and chlorobactene for the green-colored “Clc. lunatum”, and bacteriochlorophyll e and isorenieratene for the brown-colored “Plc. selenoides”. Their pigment compositions and the presence of chlorosomes attached to the inner face of the cytoplasmic membrane in both
kinds of photosynthetic cells confirmed this new half-moon-shaped morphotype as a green sulfur bacterium. Both consortia were
found thriving in lakes with low concentrations of sulfide (< 60 μM), below the layers of “Clc. aggregatum” and “Plc. roseum”. The green consortia were observed in lakes where the oxic-anoxic interface was located at shallow depths (2–7 m), while
the brown consortia were found at greater depths (8–16 m). The two newly described consortia were never detected together
at the same depth in any lake.
Received: 30 April 1997 / Accepted: 17 January 1998 相似文献
20.
Dagmar von Helversen Otto von Helversen 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,180(4):373-386
Many gomphocerine grasshoppers communicate acoustically: a male's calling song is answered by a female which is approached
phonotactically by the male. Signals and recognition mechanisms were investigated in Chorthippus biguttulus with regard to the cues which allow sex discrimination. (1) The stridulatory files on the hindfemur of both sexes are homologous
in that they are derived from the same row of bristles, but convergent with respect to the “pegs”. In males the pegs are derived
from the bristles, and in females from the wall of the bristle's cup. (2) Male and female songs are generated by similar,
probably homologous motor programs, but differ in the duration, intensity, “gappyness” of syllables, risetime of pulses, and
the frequency spectra. The hindleg co-ordination during stridulation and the resulting temporal song patterns are less variable
in males than in females. (3) For both sexes, recognition of a mate's signal depends on species-specific syllable structure.
For males it is essential that the female syllables consist of distinct short pulses, whereas females reject “gappy” syllables.
Males strongly prefer “ramped” pulses, females respond to syllables irrespective of steeply or slowly rising ramps. Males
react only to the low-frequency component, whereas females prefer spectra containing both, low and high frequency components.
Accepted: 20 November 1996 相似文献