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1.
Using scanning electron microscopy (SEM), the external morphology of all developmental stages (egg, oncomiracidium, diporpa,
just fused juvenile and adult) of the parasite, Eudiplozoon nipponicum (Monogenea, Diplozoidae), from the gills of carp was studied. During the ontogeny, the tegument, tegumentary and sensory
structures are subsequently developed. The tegument of free swimming oncomiracidium occurs in two types — the ciliated and
non-ciliated with numerous uniciliated sensory structures. An attachment apparatus starts to form during the oncomiracidium
stage. Further developmental stages are adapted to the environment of the gills. Tegumentary folds become more apparent later
in development and assist to the parasite’s attachment. In connection with its reproductive strategy, the two morphological
structures of diporpa (ventral sucker and dorsal papilla) appear to play important role. On the gills, two individuals need
to meet and these structures mediate the fusion between two diporpae. The hindbody of adult parasite is highly modified for
attachment. The haptor, folds and lobular extensions are most developed. The forebody is flexible and able to interact with
host gill tissue via the mouth and associated mouth structures. The process of food intake of the parasite was discussed. 相似文献
2.
Mohammad Mustafizur Rahman Md Yeamin Hossain Qtae Jo Su-Kyoung Kim Jun Ohtomi Carl Meyer 《Ichthyological Research》2009,56(1):28-36
In order to investigate ontogenetic changes in diet and diet overlap between rohu (Labeo rohita) and common carp (Cyprinus carpio) in polyculture ponds, food preferences of different size classes of these fishes were quantified. Rohu diet consisted of
both phytoplankton and zooplankton, and there was a distinct ontogenetic shift in the relative importance of these food items.
Zooplankton was the dominant food for rohu up to 20.6 cm total length (TL) and then gradually decreased in importance as fish
grew. Phytoplankton was initially a minor component of rohu diet but gradually increased in importance and became the dominant
food for rohu at 24.2 cm TL. Phytoplankton biovolume in rohu guts was positively correlated with fish size (TL). Chesson’s
α indicated that rohu of all sizes preferentially selected Cladocera and avoided Cyanophyceae and Euglenophyceae. Young rohu
initially preferred Rotifera and Copepoda but gradually switched to Bacillariophyceae and Chlorophyceae. Common carp diet
consisted of phytoplankton, zooplankton, and benthic macroinvertebrates, but was dominated by benthic macroinvertebrates (63–92%
of total diet). As common carp grew, the proportion of zooplankton ingested decreased and the proportion of benthic macroinvertebrates
increased. Benthic macroinvertebrate biovolume in common carp guts was positively correlated with fish size. Common carp of
up to 15.4 cm TL preferentially selected zooplankton, but common carp larger than 18.9 cm TL avoided this food item. Common
carp of all sizes avoided phytoplankton. A low dietary overlap was found between rohu and common carp (Schoener overlap index:
0.08–0.35), probably due to ingestion of smaller quantities of zooplankton by the latter. Dietary overlap also decreased with
increasing rohu and common carp size because of divergent ontogenetic shifts in dietary preferences of the two species. 相似文献
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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
6.
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
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There are three most important bacterial causative agents of serious infections that could be misused for warfare purposes:
Bacillus anthracis (the causative agent of anthrax) is the most frequently mentioned one; however, Fracisella tularensis (causing tularemia) and Yersinia pestis (the causative agent of plague) are further bacterial agents enlisted by Centers for Disease Control and Prevention into the category A of potential biological weapons. This review intends to summarize basic information about these bacterial
agents. Military aspects of their pathogenesis and the detection techniques suitable for field use are discussed. 相似文献
9.
The research on incidence of mistletoe (Viscum album ssp. abietis) on silver fir (Abies alba) was carried out in natural fir stands in Croatia. In the area of Gorski Kotar 32.8 % of the examined dominant fir trees
were infected with mistletoe. The mistletoe incidence was presented according to the damage degrees of silver fir from 0 (healthy
trees) to 4 (dead trees), rated by the crown defoliation and needle discoloration. With the increase of incidence, mistletoe
spreads more onto more vital, i.e. less damaged trees. In the Dinaric Alps 28.6% of the examined fir trees were infected,
this percentage amounting to 27.1% for the mountainous regions between the Sava and Drava rivers.
The site and stand parameters (exposure, elevation, site quality, forest community and crown closure) were analysed in order
to establish whether there was a correlation between these parameters and mistletoe incidence. There was a negative correlation
between the elevation and mistletoe incidence. Among the compartments with a closed stands there were considerably less compartments
with higher mistletoe incidence than among compartments with a sparsely closed and understocked stands. The other analysed
site and stand parameters individually had no significant influence on mistletoe incidence.
The correlation of silver fir mortality in 2004 and mistletoe incidence in 2002/03 was analysed, and their strong correlation
was established. Mistletoe could be considered as a bioindicator of silver fir decline, and probably a significant contributor
to that decline. In the areas where mistletoe incidence is great it can be presumed that silver fir is significantly damaged. 相似文献
10.
Nikoleta Karaiskou Maria Lappa Stefanos Kalomoiris George Oikonomidis Chariklia Psaltopoulou Theodore J. Abatzopoulos Costas Triantaphyllidis Alexander Triantafyllidis 《Conservation Genetics》2011,12(5):1299-1311
The ability to detect genetic differences both in space and time is crucial for conserving genetic variation. It can reveal
genetic diversity and genetic composition changes of declining native populations that are supported through stocking with
captive bred individuals. The present study was designed to analyse the temporal stability of a declining common carp (Cyprinus carpio) population from Lake Volvi (North Greece). Polymorphism was evaluated using seven microsatellite loci at two sampling time
points (separated by 12 years). The genetic variability of four additional populations (from two rivers and two lakes) in
Northern Greece was also investigated for comparison. Heterozygosity values (0.692–0.868) and allelic richness (8.530–11.148)
were high for all studied populations and comparable to other European populations. However, the analysis of temporal common
carp samples from Lake Volvi revealed a significant change in their genetic composition and admixture analysis demonstrated
significant introgression of stocked individuals into the native population. Both temporal and point estimate methods revealed
low effective size (Ne = 61–171.3) for this population, possibly a result of an ancient genetic bottleneck that led to population decline and/or
recent anthropogenic interventions. This low Ne has rendered the native population vulnerable to alteration of its genetic composition. Our study demonstrates that enhancement
programs should be applied cautiously, especially for small populations. Moreover, it underlines the need for temporal analyses,
which may contribute to the evaluation of previous management policies and to future decision making. 相似文献
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N. Yu. Markelova 《Microbiology》2010,79(6):777-779
Interaction of Bdellovibrio bacteriovorus 100NCJB with bacteria Campylobacter jejuni (strains 1, 2, 3, 4, and 5) and Helicobacter pylori, strain TX30a, was confirmed. The results indicate that lytic activity of bdellovibrios both in liquid media and cells attached
to a surface was observed. The potential use of the antimicrobial activity of predatory bacteria for environmental bioprotection
and public health is discussed. 相似文献
13.
D. A. Balashov A. V. Recoubratsky L. N. Duma E. V. Ivanekha V. V. Duma 《Russian Journal of Developmental Biology》2017,48(5):347-353
Fertility of backcross triploid hybrids containing one genome of Prussian carp and two genomes of common carp is investigated. The females of hybrids of Prussian carp and common carp (Prussian × common carp) are prolific and produce diploid gametes. Since males of such hybrids are sterile, their reproduction is realized by means of induced gynogenesis. Triploid progeny is obtained by backcrossing female Prussian × common carp with carp males. Among triploids obtained from hybrids F1 and among hybrids of the first gynogenetic generation, there were no prolific specimens. However, in reproduction of diploid hybrids by means of gynogenesis during six generations, the female fertility in the backcross progeny is restored. From backcross triploid females (daughters of Prussian × common carp of the sixth gynogenetic generation), a viable triploid gynogenetic progeny and a tetraploid backcross (by carp) progeny are obtained. The obtained data may be considered as the experimental proof of the hypothesis of reticular speciation. 相似文献
14.
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
15.
The use of lignocellulose as a source of sugars for bioproducts requires the development of biocatalysts that maximize product
yields by fermenting mixtures of hexose and pentose sugars to completion. In this study, we implicate mgsA encoding methylglyoxal synthase (and methylglyoxal) in the modulation of sugar metabolism. Deletion of this gene (strain
LY168) resulted in the co-metabolism of glucose and xylose, and accelerated the metabolism of a 5-sugar mixture (mannose,
glucose, arabinose, xylose and galactose) to ethanol. 相似文献
16.
Ferruh Aşçi 《Biologia》2009,64(6):1146-1149
In this study, the structural characteristics, unique features, various organ measurements of males and females of the water
mite Atractides (Atractides) turcicus sp. n. from Turkey are described. In addition, the study compares their characteristics with related species. 相似文献
17.
O. V. Golovanova V. I. Konenkov A. V. Shevchenko M. V. Smolnikova 《Russian Journal of Genetics》2009,45(8):981-986
Based on population analysis of the DRB1, DQA1, DQB1 and TNFA allele frequency distribution patterns, regional features of immunogenetic structure of the population of West Siberia were
investigated. Statistically significant linkage disequilibrium within the HLA class II region, as well as between the TNFA and DRB1, DQA1, and DQB1 was demonstrated. Population frequency distribution patterns of two- and multilocus haplotypes were examined. 相似文献
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The present study is aimed at recording changes in taste preferences and behavior related to testing of artificial agar-agar
(2%) pellets with free amino acids (21 amino acids, L-isomers, 0.1–0.001 M) in the carp Cyprinus carpio at increasing duration of starvation (2, 12, 18, 24, 72, and 144 h). Two hours after the end of feeding until satiation,
the fish manifest a low foraging activity and, in most cases, they do not grasp the offered pellet. Later on, the feeding
motivation in fish increases rapidly and up to 24 h of starvation each of the offered pellets is grasped. In the first hours
of starvation the fish refuse from consumption of the grasped pellets even with highly attractive taste stimuli (extract of
chironomids, cysteine). Up to 24 h of starvation, the fish restore the differentiated attitude to taste properties of amino
acids. Of the latter, four amino acids increase, six decrease, and the other 11 do not render significant influence on consumption
of pellets. Up to 72 h of starvation, at the background of continuing increase in the absolute level of consumption of pellets
of all types, the taste preferences change but weakly. However, up to 144 h of starvation the number of deterrent amino acids
was reduced to one (phenylalanine). At increasing duration of starvation, the number of repeated grasping of pellets changes
weakly while duration of testing by fish of pellets of most types increases, especially abruptly in the first 24 h. It is
assumed that the decrease or complete loss in fish of the negative reaction to substances, initially having aversive taste
properties may be considered as the main mechanism providing expansion of the feeding spectrum and/or transfer of fish onto
consumption of new items, initially consumed just occasionally or fully avoided. 相似文献
20.
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