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1.
Swimming and diving abilities of two syntopic species of water shrews, Neomys anomalus and Neomys fodiens, were tested in aquaria using video recordings taken from three views (lateral distant, lateral close and dorsal). The frequency
and total duration of diving, as well as the mean duration of diving and floating bouts, were significantly higher in N. fodiens than in N. anomalus. Frequency of paddling during surface swimming was lower in N. fodiens than in N. anomalus. N. fodiens dived mainly for long distances at the bottom of the aquarium and performed a wider range of dive profiles than N. anomalus, which preferred rather short and shallow dives. The two species differed also significantly in their fineness ratios (describing
how streamlined their bodies are) when diving. When swimming, N. fodiens had a relatively wider body and performed narrower movements with its tail than N. anomalus. These results show quantitatively and qualitatively for the first time that N. fodiens is more proficient at swimming and diving than N. anomalus. The results also help to explain the inter-specific differences in efficiency of underwater foraging, and support the idea
of segregation of ecological niches of these species based on their different foraging modes (diving vs. wading). 相似文献
2.
We provide observational and experimental evidence that territorial males of the maternal harvestman Acutisoma proximum temporarily care for clutches that are left unattended by females from their harems. The evolution of paternal care in harvestmen
from a territory-based polygynous mating system is discussed.
Received 5 August 2008; revised 13 and 29 October 2008; accepted 25 November 2008 相似文献
3.
Summary. The paper describes two methods of the synthesis of ethyl (3R,4S)- and (3S,4S)-4-[(benzyloxycarbonyl)amino]-5-[(tert-butyloxycarbonyl)amino]-3-hydroxypentanoates, useful for the syntheses of edeine analogs. Differently N-protected (S)-2,3-diaminopropanoic acid was used as a substrate in both procedures. The absolute configuration of newly generated asymmetric
carbon atoms C-3 in β-hydroxy-γ,δ-diamino products was assigned by means of 1H NMR spectroscopy after their transformation into corresponding piperidin-2-ones.
Received May 24, 2002 Accepted October 10, 2002 Published online December 18, 2002
Acknowledgment The authors are indebted to the Faculty of Chemistry, Technical University of Gdańsk for financial support.
Authors' address: Zbigniew Czajgucki, M. Sc., Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Technical University
of Gdańsk, 11/12 Narutowicza St., 80-952 Gdańsk, Poland, Fax +48 58 347 11 44, E-mail: zmczaj@wp.pl 相似文献
4.
Gwénaelle Crénès Corinne Moundras Marie-Véronique Demattei Yves Bigot Agnès Petit Sylvaine Renault 《Genetica》2010,138(5):509-517
The eukaryotic transposon Mos1 is a class-II transposable element that moves using a “cut-and-paste” mechanism in which the transposase is the only protein
factor required. The formation of the excision complex is well documented, but the integration step has so far received less
investigation. Like all mariner-like elements, Mos1 was thought to integrate into a TA dinucleotide without displaying any other target selection preferences. We set out to
synthesize what is currently known about Mos1 insertion sites, and to define the characteristics of Mos1 insertion sequences in vitro and in vivo. Statistical analysis can be used to identify the TA dinucleotides that are non-randomly
targeted for transposon integration. In vitro, no specific feature determining target choice other than the requirement for
a TA dinucleotide has been identified. In vivo, data were obtained from two previously reported integration hotspots: the
bacterial cat gene and the Caenorhabditis elegans rDNA locus. Analysis of these insertion sites revealed a preference for TA dinucleotides that are included in TATA or TA × TA
motifs, or located within AT-rich regions. Analysis of the physical properties of sequences obtained in vitro and in vivo
do not help to explain Mos1 integration preferences, suggesting that other characteristics must be involved in Mos1 target choice. 相似文献
5.
The pollination of one plant species can be facilitated by the presence of one or more neighboring plant species and evidence
has been found in some rewardless species of orchid that benefit from the presence of rewarding plant species in the neighborhood.
There are two pollination mechanisms by which a non-rewarding orchid attracts pollinators and increases its reproductive success:
(1) A magnetic species effect that occurs even though the flowers do not resemble those of the other species, and (2) floral
mimicry where the mimic’s flower resembles that of the model plant species. Oncidium cosymbephorum is a Mexican rewardless epiphytic orchid whose flowers look like those of the rewarding shrub Malpighia glabra (Malpighiaceae). The resemblance of O. cosymbephorum to the oil-offering flowers of M. glabra attracts the same pollinators, and the fitness of the orchid is higher when M. glabra is present than when it is absent. We evaluated the facilitation by M. glabra of the orchid’s pollination for natural and artificial clumps of O. cosymbephorum close to and far from M. glabra over 4 years. Two experiments were performed at five different study sites to evaluate the effect of the presence and absence
of M. glabra on the reproductive success of O. cosymbephorum. In experiment 1, we recorded fruit set production in natural and artificial monospecific clumps of the orchid, and in natural
and artificial heterospecific clumps of O. cosymbephorum and M. glabra. In experiment 2, we recorded the fruit set of O. cosymbephorum at different sites where individuals grow in monospecific clumps, both before and after cultivated individuals of oil-producing
M. glabra had been planted in their vicinity. Both experiments showed that the reproductive success of O. cosymbephorum was greater in the presence of M. glabra than it was in its absence. This study provides experimental evidence for the magnetic species effect. Floral similarity
between O. cosymbephorum and M. glabra, should be experimentally tested to determine whether it is adaptive. 相似文献
6.
Antinutritional effects of acorns and tannic acid on the Japanese wood mouse Apodemus speciosus were examined in the laboratory. The first feeding experiment was conducted for 15 days using three types of diet: control
diet (laboratory chow for mice), acorns of Quercus serrata (QS), and acorns of Q. mongolica var. grosseserrata (QM), which differ in tannin content (control, tannin free; QS, 2.7% tannic acid equivalent; QM, 8.5%). Six and one of eight
mice died in the QM and QS groups, respectively, whereas all mice survived in good health in the control group. Body weight
in the QM and QS groups decreased as much as 23.6% and 16.8% in the first 5 days, respectively, whereas that in the control
group did not change significantly. Dry matter intake in the QM group was 50.0% and 38.7% less than that in the control and
QS, respectively. Apparent dry matter digestibility was not different among the diets, but apparent nitrogen digestibility
did differ between the two acorn groups (QM, −17.5%; QS, 12.0%). The logistic regression analyses revealed that the survival
of mice was synergistically influenced by both dry matter intake and apparent nitrogen digestibility. In the second experiment,
wood mice fed the tannin-free formula diet, which is nutritionally matched to QS and QM acorns except for the tannin, did
not suffer antinutritional effects, whereas mice fed the tannin-supplemented formula diets suffered body weight loss and negative
nitrogen digestibility. These results indicate that the tannins in acorns could cause serious damage to the wood mouse, which
may rely on acorns as a usual diet. Plausible hypotheses explaining how the wood mice could overcome the deleterious effects
of the acorns are discussed.
Received: May 9, 2002 / Accepted: December 6, 2002 相似文献
7.
Nathália S. Fernandes Estefanía Stanley Fernando G. Costa Carlos A. Toscano-Gadea Rodrigo H. Willemart 《Acta ethologica》2017,20(3):215-221
Several arachnid species use chemicals to detect sexual partners. In harvestmen, there are evidences that chemicals may play a role in intraspecific communication. Using the behavior of Discocyrtus prospicuus (Holmberg 1876), whose males expose the penis to females before they engage in mating posture, we tested if males detect females by contact chemoreception (chemicals left on the substrate) and if males detect females by olfaction. First, we exposed males to three experimental groups, where males had to choose between two substrates: female chemicals/blank control; male chemicals/blank control; female/male chemicals. Then, we gave males access to volatiles of males, females, and control simultaneously. We predicted that males would expose the penis when approaching volatiles and chemicals deposited on the substrate by females. We also tested if males spent more time close to the source of female volatiles and on the substrate with female chemicals and if males tapped the substrate with female chemicals for more time than the others. Finally, we put males and females together to observe if males would expose the penis upon touching the female’s cuticle. Most of our predictions were not supported, though males did tap for more time when exposed to female cues instead of male cues and exposed the penis in 70% of the observations when interacting with the female but only after touching her. Our data does not support olfaction as a way to detect females and corroborate the idea that contact chemicals, either on the substrate or on female’s cuticle, play an important role in the detection and recognition of the opposite sex. This is the first evidence in harvestmen that males may react differently to female/male chemicals. 相似文献
8.
The conservation problems affecting the endangered rodent Microtus cabrerae are mainly related to habitat loss and fragmentation. In the present study, we examined the presence/absence of the species
in a group of potentially suitable habitat patches, and then evaluated the microhabitat attributes of locations used by wild-ranging
individuals within occupied patches. Our results revealed that shallow flooding and abundant grass cover appear to be important
factors in determining the presence among localities, but high rush cover strongly determined the presence and habitat use
by voles both among and within localities. The preservation of these microhabitat characteristics may be required to effectively
ensure the occurrence and stability of M. cabrerae colonies. 相似文献
9.
Takehiko Yamanaka Koichi Tanaka Akira Otuka Ottar N. Bjørnstad 《Ecological Research》2007,22(2):185-196
We observed a weed (Ambrosia artemissifolia)–beetle herbivore (Ophraella communa) system for three years in a spatially continuous field (≈200 ha). We analyzed our field data in the light of two contrasting
theories: the resource-concentration hypothesis and reaction–diffusion theory. For the resource-concentration hypothesis, we calculated the correlation coefficients between weed and beetle abundances
for every season in each year. Although we found weak support for resource concentration in some seasons, we could not find
any clear relationships in other seasons. We discuss a dispersal-based mechanism to explain the differences observed among
seasons in lieu of the resource-concentration hypothesis. For the reaction–diffusion theory, we estimated the nonparametric
spatial covariance functions for the spatial autocorrelation of weeds and beetles. Although we could not find any strong spatial
structure for the individual species, we found evidence of spatial interactions between weeds and beetles using time lagged
cross-correlation functions. Weed abundance enhanced local beetle abundance. Through time, there was evidence of beetle spillover
to adjacent locations at roughly the one beetle-generation time scale. Sites with large number of beetles did not seem to
reduce subsequent weed abundance. 相似文献
10.
Michael G. Boegle Susanne Schneider Beate Mannschreck Arnulf Melzer 《Hydrobiologia》2007,586(1):155-166
11.
R. Ramirez-Malagon I. Aguilar-Ramirez A. Borodanenko L. Perez-Moreno J. L. Barrera-Guerra H. G. Nuñez-Palenius N. Ochoa-Alejo 《In vitro cellular & developmental biology. Plant》2007,43(6):660-665
Mammillaria species are the most numerous within Cactaceae family, and some of them are threatened with extinction as a result of human
activities. In this work, results of in vitro propagation are presented for ten Mammillaria species, testing 20 combinations of indole-3-acetic acid (IAA) and kinetin. Best results on shoot formation were obtained
using kinetin at two levels: 27.9 and 46.5 μM. All IAA levels tested were able to induce de novo shoot formation in M. bocasana, M. densispina, M. hahniana, M. hutchisoniana, M. orcutii, M. pectinifera, M. perbella, M. picta, M. rhodantha, and M. zephyranthoides. Depending on the IAA level tested, four responding groups were observed concerning their highest shoot-formation number.
For all species, the highest average of shoot formation was achieved with 5.7:46.5 or 11.4:46.5 μM IAA/kinetin, yielding 4.8
and 4.7 shoots per explant, respectively, in 60 d. Rooting of regenerated shoots was achieved by leaving the explants in their
shoot-induction medium or transferring them to half-strength MS medium. Hardening of regenerated plants was successfully achieved
by planting them in peat moss substrate after a desiccation treatment at room temperature for 3 d. 相似文献
12.
Marianne Peroutka Wolfram Adlassnig Michael Volgger Thomas Lendl Walter G. Url Irene K. Lichtscheidl 《Plant Ecology》2008,199(2):153-162
Aquatic carnivorous plants of the genus Utricularia capture and utilise a wide range of small aquatic organisms. Most of the literature focuses on animals as prey. In this study,
we investigate the occurrence of algae inside the traps of four species of bladderwort. We observed that algae of 45 genera
form up to 80% of the total prey; algae were found frequently in traps without animal prey. The majority are coccal and trichal
algae of the families Desmidiaceae and Zygnemataceae. The percentage of algae increases significantly with decreasing electric
conductivity of the water (r
S = −0.417; P = 0,000). Thus, algae are the most frequent prey in extremely soft waters. The percentage of algae did not differ significantly,
not within the investigated Utricularia species or within the various study sites. However, the taxonomic composition of the algal prey showed highly significant
differences between different sites. More than 90% of the trapped algae were killed and degraded by the bladders. The recent
data allow for two alternative hypotheses: either algal prey supplements animal prey in oligotrophic waters, or the unprofitable
trapping of algae is rather an additional stress factor for Utricularia and contributes to its limited distribution in some peat bogs. 相似文献
13.
Dario Kremer Edith Stabentheiner Želimir Borzan Renata Jurišić Grubešić 《Biologia》2008,63(6):1111-1117
Micromorphological differences in leaves and pollen between two American (Fraxinus americana L., F. pennsylvanica Marshall) and two European (F. angustifolia Vahl, F. excelsior L.) ash species were studied using scanning electron microscope. The types, dimensions and distribution of characteristic
trichomes were established and measured. Capitate hairs on the leaves had the same shape in all researched ash species. Acicular
hairs were regularly present in two American ash species, but very rarely in the glabrous phase of F. angustifolia and F. excelsior. Only F. americana had coronulate abaxial surface of leaves. Pollen of F. angustifolia and F. excelsior had 3 (tricolpate) apertures, and F. americana and F. pennsylvanica 4 (stephanocolpate) apertures. Based on the appearance of the reticulum it’s possible to clearly distinguish all four species.
F. angustifolia and F. pennsylvanica had muri with transversal ridges and seldom granules. Muri of F. excelsior and F. americana had slightly visible transversal ridges, and because of that noticeable granules. 相似文献
14.
Appearance and location of 45S rDNA and 5S rDNA signals were compared in chromosomes of nine species of the aneuploid Zamia and their taxonomically and phylogenetically closely related Ceratozamia mexicana. The 45S rDNA signal was detected in the proximal region of six chromosomes in Zamia angustifolia, Z. integrifolia, Z. pumila and Z. pygmaea (all 2n=16); in the proximal region of 6–14 chromosomes in Z. furfuracea, Z. loddigesii, Z. skinneri and Z. vazquezii (all 2n=18); and on the proximal region of 20 chromosomes in Z. muricata (2n=23). The 5S rDNA signals were commonly seen near the terminal region of the short arm of two metacentric chromosomes
in the four species with 2n=16 and Z. furfuracea, Z. loddigesii and Z. vazquezii with 2n=18. Other 5S rDNA signals were seen near the terminal region of two terminal-centromeric chromosomes in Z. skinneri and near the terminal region of a metacentric and a telocentric chromosomes in Z. muricata. In contrast, those with 45S and 5S rDNA signals were exhibited in chromosomes of Ceratozamia mexicana in a different manner from those in the nine species of Zamia; the 45S rDNA signal in the terminal region of four metacentric and two submetacentric chromosomes and the 5S rDNA signal
near the proximal region of two metacentric chromosomes.
Received November 1, 1999 Accepted January 10, 2001 相似文献
15.
The life cycle and developmental stages of Aylax hypecoi (Trotter, 1913, Hymenoptera: Cynipidae: Aylacini) were studied in detail. Aylax hypecoi is known to induce galls in fruits of two Hypecoum species — H. imberbe and H. geslini (Papaveraceae) and the larva develops in host plant fruits. The morphology and development of egg, larva and pupa were investigated, which
has previously not been done. The shape and size of terminal-instar larvae and associated galls are sex-specific. Overwintering
stage, adult emergence and flying periods, and egg productivity were studied also. 相似文献
16.
In April 2001, a 9-year-old child was attacked and killed by dingoes on Fraser Island, Australia. The Dingo Management Strategy
formulated in response to this incident proposed ultrasonic deterrents as one of a number of non-lethal management techniques
requiring further investigation. In this paper, we describe a preliminary examination of an ultrasonic deterrent to dingoes
using four captive animals as test subjects. Although replication was minimal, the use of a simple experimental design, in
combination with a flexible analytical technique, sufficiently demonstrated that the unit tested produced no measurable effect
as a deterrent to test subjects. 相似文献
17.
Khomaini Hasan Wangsa Tirta Ismaya Idar Kardi Yandi Andiyana Susanti Kusumawidjaya Safri Ishmayana Toto Subroto Soetijoso Soemitro 《Biologia》2008,63(6):1044-1050
α-Amylase from Saccharomycopsis fibuligera R-64 was successfully purified by butyl Toyopearl hydrophobic interaction chromatography, followed by Sephadex G-25 size
exclusion and DEAE Toyopearl anion exchange chromatography. The enzyme has a molecular mass of 54 kDa, as judged by SDS PAGE
analysis. Upon tryptic digestion, two major fragments with relative molecular masses of 39 kDa and 10 kDa, which resemble
the A/B and C-terminal domains in the homologous Taka-amylase, were obtained and were successfully separated with the Sephadex
G-50 size exclusion column. The 39-kDa fragment demonstrated a similar amylolytic activity to that of the undigested enzyme.
However, it was found that the K
m value of the 39-kDa fragment was about two-times higher than that of the undigested enzyme. Moreover, thermostability studies
showed a lower half-life time for the 39-kDa fragment. These findings suggest that the 39-kDa fragment is the catalytic domain,
while the 10-kDa fragment is the C-terminal one, which plays a role in thermostability and starch binding. Although the undigested
enzyme is able to act on raw starches at room temperature, with maize starches as the best substrate, neither the undigested
enzyme nor the fragments adsorb the tested raw starches. These results propose Saccharomycopsis fibuligera α-amylase as a raw starch-digesting but not adsorbing amylase, with a similar domain organization to that of Taka-amylase A. 相似文献
18.
Marcin Sielezniew Izabela Dziekańska Anna M. Stankiewicz-Fiedurek 《Journal of Insect Conservation》2010,14(2):141-149
Phengaris (=Maculinea) arion is an endangered social parasite of Myrmica ants, and for a very long time was considered as specific to Myrmica sabuleti. Previous studies carried out in Poland suggested some discrepancies within this assumption, and therefore a much more intensive
survey was undertaken. The host ant use of P. arion was studied at five sites in different types of biotopes in Poland, i.e. xerothermal grasslands where Thymus pulegioides was used as a larval food plant by the butterfly, and more or less sandy biotopes with Thymus serpyllum. Altogether nine Myrmica species were recorded, and considerable variation in species composition and density of nests was recorded. At four localities
M. sabuleti proved to be the most common ant. A total of 529 Myrmica nests were examined, and only 20 of them contained larvae and pupae of P. arion. Host ants belonged to five different species, i.e. M. sabuleti, Myrmica scabrinodis, Myrmica schencki, Myrmica lobicornis and Myrmica hellenica. Only at one site (NE Poland) was a significant heterogeneity in parasitation rates among Myrmica species detected. M. lobicornis was the most often infested ant there, which may suggest local specialisation of the butterfly. Overall low parasitism rates
may explain the vulnerability of P. arion in Central Europe but further studies are also necessary. 相似文献
19.
Following a re-examination of the material treated under Barleria brevispina (Fiori) Hedrén in the recent Flora of Somalia account of the Acanthaceae, it is concluded that two distinct species are involved and Barleria compacta Malombe & I. Darbysh. is described here from north-eastern Somalia. Its affinities and conservation status are discussed. 相似文献
20.
Some burrower bugs (Heteroptera: Cydnidae) show complex patterns of maternal care, including defense against predators and
the provisioning of food to nymphs. Recently, the subsocial cydnid bugs have attracted the interest of researchers as model
systems to study the behavioral ecology of parental investment. However, there have been few attempts to quantify the fitness
benefits of maternal behavior other than provisioning. Here, we examined the maternal behavior of Adomerus triguttulus and its adaptive significance in terms of offspring survival in the field. A. triguttulus young depend on fallen nutlets of myrmecophorous mints, Lamium spp. Under field conditions, females attend offspring, from eggs to second instar nymphs, in nests on the ground under the
litter. When disturbed, the females showed aggressive responses against the source of disturbance. The females often carried
spherical clutches of eggs away from the nest when heavily disturbed. Female-removal experiments in the field demonstrated
a defensive function of the female behavior; predators, such as ants, attacked egg clutches without females and the clutches
often disappeared during the experiment. Egg clutches without females sometimes also suffered from fungal infection. Selective
factors on maternal defensive behavior in A. triguttulus are discussed in terms of habitat properties possibly emerging from insect–plant associations. 相似文献