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1.
The polaroplast of microsporidium from copepod Mesocyclops leuckartii was studied by transmission electron microscopy. The polaroplast differs from all previously described types by complex structure. 相似文献
2.
Micieli MV Marti GA García JJ Tranchida MC Becnel JJ 《Journal of invertebrate pathology》2007,94(1):31-37
The epizootiology of Amblyospora camposi was studied in a natural population of Culex renatoi, a bromeliad-inhabiting mosquito, and its intermediate host, Paracyclops fimbriatus fimbriatus, over a 2-year period. Twenty Eryngium cabrerae plants were sampled monthly from January 2003 to January 2005 and the prevalence of A. camposi in P.f. fimbriatus and Cx. renatoi populations was determined. The monthly prevalence rates of meiospore infections in Cx. renatoi larvae never exceeded 5.5% and was detected in 50% of the monthly samples. Meiospores were available in plants over the course of the study at a mean concentration of 2 x 10(4) meiospores/ml. Within each plant the parasite was maintained by horizontal transmission. P.f. fimbriatus with vegetative stages and mature spores were found regularly in bromeliads suggesting efficient meiospore infectivity to field copepod populations. The mean concentration of spores from copepods found in plants was 8 x 10(2) spores/ml. Infections in copepods were detected in 54% of the monthly samples with a prevalence rate ranging from 0.55 to 17.4% and an overall average of 5.1%. Vegetative stages in fourth instar mosquito larvae (probably derived from the horizontal pathway via spores formed in copepods) were detected in 12.5% of the monthly samples with an overall prevalence rate of 1.1%. Infections in female and male adults were detected in 20.8% of the monthly samples with an overall average of 4.1% and 6.8%, respectively. 相似文献
3.
Comparative small subunit rDNA sequence analyses, indicate that Ovavesicula popilliae, a microsporidian parasite of the Japanese beetle, Popillia japonica, represents a distant sister group to Paranosema and Antonospora. These three genera represent a second major group (the Nosema/Vairimorpha clade representing the first) of Microsopridia which infect terrestrial insects, suggesting independent origins for both groups. Phylogenetic analyses of Ovavesicula and other Microsporidia having a multi-sporous sporogony reveal that this condition is found in several unrelated taxa implying either that multi-sporous sporogony is the ancestral condition for Microsporidia or that it has multiple origins. 相似文献
4.
Comparative phylogenetic analysis of the small subunit rDNA sequence of Octosporea muscaedomesticae (Flu, 1911) (type species) (Microsporidia) isolated from the blowfly Phormia regina (Diptera:Calliphoridae) is presented. Neighbor Joining bootstrap, Maximum Parsimony and Maximum Likelihood analyses with 38 microsporidian taxa representing five major clades of Microsporidia placed O. muscaedomesticae on a separate branch within a clade containing parasites of freshwater hosts. O. muscaedomesticae differed from Octosporea bayeri, a parasite of the microcrustacean, Daphnia magna (Cladocera:Daphniidae) by 29% demonstrating that the latter microsporidium is not closely related to the type species at the generic level, and should not be placed within the genus Octosporea, a conclusion that is further supported by morphological and developmental differences. Considering the number of disparately related hosts from which Octosporea species have been previously described based mostly on developmental and morphological characters it is likely that many will not fit the current definition of the genus, and it is possible that molecular analysis of these species will show that this genus as defined represents a polyphyletic grouping of unrelated taxa. 相似文献
5.
Paracyclops longispina n. sp. and Paracyclops altissimus n. sp. are described. New characters derived from detailed examination of body and limb ornamentation are used to differentiate them from other Paracyclops species. Paracyclops longispina n. sp. resembles Paracyclops fimbriatus (Fischer, 1853) and Paracyclops imminutus Kiefer, 1929. It differs from the former by the presence of a well-developed spinular row near the base of the inner setae on the antennal coxobasis in both sexes, and from the latter in the structure of the seminal receptacle and the position of the mid-distal spinular row on the posterior surface of the coxa of leg 1. Paracyclops altissimus n. sp. can be distinguished from other members of genus mainly by the structure of the seminal receptacle and leg 5. This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
Ashworth M. P. Spalding H. L. Hanisak M. D. Fawley M. W. Buchheim M. A. & Zechman F. W. 《Journal of phycology》2003,39(S1):1-2
Palmophyllum, Verdigellas and Palmoclathrus are marine palmelloid green algae with morphologies ranging from closely adherent crusts, peltate discs, to upright branched thalli. Thalli of these taxa are comprised of small spherical cells embedded within a dense mucilaginous matrix. Taxonomic affinities of these palmelloid genera, however, has remained uncertain. Previous studies of Palmophyllum and Verdigellas classified these algae within the Palmellaceae, but the complete absence of data regarding reproduction have blurred ordinal designations. Generally, these algae have been classified as members of the Tetrasporales within the class Chlorophyceae, but the Chlorococcales has also been proposed. Global analyses of eukaryotic nuclear-encoded small subunit rDNA sequences based on parsimony (MP), neighbor joining (NJ) and likelihood (ML) methods confirm the placement of Palmophyllum and Verdigellas as a monophyletic group within the Chlorophyta, but class and ordinal affinities were not clearly resolved. ML suggested that Verdigellas and Palmophyllum are members of a clade with coccoid prasinophyte algae at the base of the Chlorophyta, while NJ and ML suggested that the palmelloid genera formed a basal lineage of the Viridiplantae. A consistent feature of all analyses, however, is that Verdigellas and Palmophyllum did not group with the chlorophycean orders, Tetrasporales or Chlorococcales. Results will be discussed in the context of taxonomy, character evolution, and implications for green plant evolution. (Supported in part by NSF grants DEB-0128952 to MWF, DEB-0129030 to MAB, and DEB-0128977 to FWZ) 相似文献
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A comparative analysis of ultrastructure of some organelles stained by different methods of staining of ultrathin sections
has been performed using the example of intracellular parasites, i.e., microsporidia. The distinctive peculiarities are revealed
and the advantages and disadvantages are substantiated of the traditional method of contrasting with uranyl acetate and the
nontraditional method of contrasting using black Chinese tea extract, i.e., oolong tea extract (OTE). The OTE-staining method
dies the basic intracellular structures of microsporidia, which is a matter of taxonomic significance; it also reveals additional
layers of the polar filament with more distinct boundaries between them. However, traditional UA-staining better reveals some
structures (membranes, layers of envelope of mature spores, structure of the rough endoplasmic reticulum, Golgi complex, nuclear
chromatin) and provides for higher general contrast. The OTE solution is safe to use and can be longer kept in light at room
temperature without losing its activity. However, the OTE-method is time-consuming. Hence, this staining method has both advantages
and disadvantages. On the whole, it can be used as an alternative to the traditional staining with uranyl acetate. 相似文献
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10.
Andreadis TG 《Journal of invertebrate pathology》2002,81(2):114-121
The epizootiology, transmission dynamics and survival strategies employed by the microsporidium Hyalinocysta chapmani were examined in field populations of its primary mosquito host, Culiseta melanura and its intermediate copepod host, Orthocyclops modestus over a three-year period in an aquatic subterranean habitat. H. chapmani was enzootic and was maintained in a continuous cycle of horizontal transmission between each host. There were three distinct periods during the summer and fall when developing mosquito larvae acquired infections; each was preceded by or coincident with the detection of infected copepods. Results were corroborated in laboratory bioassays, wherein transmission was achieved in mosquito larvae that were reared in water and sediment samples taken from the site during the same time periods. The highest infection rates, ranging from 60% to 48%, were repeatedly observed during the first six weeks of larval development. These were coincident with the most sustained collections of infected copepods obtained during the year and highest levels of infection achieved in the laboratory transmission studies. The high prevalence rates of lethal infection observed in larval populations of C. melanura at this site are among the highest recorded for any mosquito-parasitic microsporidium and clearly suggest that H. chapmani is an important natural enemy of C. melanura. H. chapmani appears to overwinter in diapausing mosquito larvae but may also persist in copepods. The absence of vertical transmission in the life cycle of H. chapmani and the sole reliance on horizontal transmission via an intermediate host are unique survival strategies not seen among other mosquito-parasitic microsporidia. The epizootiological data suggest that this transmission strategy is a function of the biological attributes of the hosts and the comparatively stable environment in which they inhabit. The subterranean habitat is inundated with water throughout the year; copepods are omnipresent and C. melanura has overlapping broods. The spatial and temporal overlap of both hosts affords abundant opportunity for continuous horizontal transmission and increases the likelihood that H. chapmani will find a target host. It is hypothesized that natural selection has favored the production of meiospores in female host mosquitoes rather than congenital transfer of infection to progeny via ovarian infection as a strategy for achieving greater transmission success. 相似文献
11.
The female reproductive cycles of the calanoid copepod
Copidodiaptomus numidicus and the cyclopoid
Acanthocyclops robustus were characterized by periodic
changes in the oviducts. Females oscillated between a gravid and a
non-gravid condition, and the whole cycle was strongly dependent on
temperature. In both species, the maturation of new oocytes took place when
the old egg sacs were still being carried, thus ensuring a rapid clutch
succession. The embryonic and post-embryonic development duration of
C.numidicus and A.robustus was
investigated at five and four different temperatures, respectively.
Embryonic development time was related to oviductal cycle duration at each
temperature to estimate the minimum amount of non-ovigerous females
expected under non-limiting mate and food conditions.
Copidodiaptomus numidicus females spent 35-19% of the
cycle without carrying eggs at 7-20C.
Acanthocyclops robustus females spent 31-33% of the
cycle without carrying eggs at the same temperature interval. Both naupliar
and copepodid durations were inverse functions of temperature with nauplii
developing at a faster rate than copepodids. In general,
A.robustus showed reproductive advantage over
C.numidicus due to a faster oviductal cycle and
shorter embryonic and post-embryonic development times. However, the
influence of food quality may be crucial. Acanthocyclops
robustus copepodid development may lengthen well beyond the
corresponding development stages of C.numidicus when
growing only on algae. This retardation of development affects especially
the later development stages of the cyclopoid.
相似文献
12.
Andrzej Ko?aczyński 《ZooKeys》2015,(522):141-152
A new species of Metacyclops is described from hyporheic waters and small rock depression with leaf litter in North Vietnam, the Tam Đao Mountains). Metacyclops
amicitiae
sp. n. can be distinguished from its congeners by the unique combination of the following characters: 12-segmented antennule, distal segment of P4 endopodite bearing a single apical spine, and the surface ornamentation of the intercoxal sclerites in P1–P4 (pilose on the distal margin of P1-P4 and spinulose on the caudal surface of P4). The latter character separates the new Metacyclops from its closest relative, Metacyclops
ryukyuensis, known only from the Ryukyu Islands (Ishigaki). The genus Metacyclops with the new species described herein is also for the first time recorded from Vietnam. An identification key is provided to the south and east Asian species of the genus. 相似文献
13.
Isabella Van de Velde 《Hydrobiologia》1984,109(1):3-66
A revision is made of the African Mesocyclops species, based on type material (when extant) and on collections from various parts in Africa.Diagnostic characteristics are: presence or absence of spinule patterns on antennular segments, structure of the hyaline membrane of the 17th antennular segment, spine pattern on the basipodite of the antenna, armature of the maxillulary palp, presence or absence of a spine on the basipodite of P1, armature of the connecting lamella, coxopodite and basipodite of P4, armature of the apical spines of Enp3P4, armature of the last thoracic segment, genital segment and the other abdominal segments, armature of the furcal rami and structure of the receptaculum seminis.First, the taxonomical status of M. leuckarti (Claus) is redefined; this species does not occur in Africa and its geographical range is restricted to Europe and the western part of Northern Asia. On the African continent, twelve other taxa are found. Four are described as new to science: M. kieferi sp.n., M. dussarti sp.n., M. spinosus sp.n. and M. aequatorialis similis subsp.n. The remainder are: M. major Sars, M. tenuisaccus (Sars), M. paludosus Lindberg, M. salinus Onabamiro, M. ogunnus Onabamiro, M. aspericornis (Daday), M. rarus Kiefer and M. aequatorialis aequatorialis (Kiefer).Their geographical distribution is discussed. Eleven taxa are restricted to the African continent (including the Arabian Peninsula and the Canary Islands). One taxon is also found in the Oriental Region. Madagascan representatives are briefly mentioned.The importance of breeding and cross-breeding experiments should be stressed in copepod taxonomy. Experiments were performed on African species and M. leuckarti to evaluate the morphological characters used in the present study, and intraspecific morphological variability was examined up to and including the third generation (Van de Velde, in press).In future one should critically reconsider the so-called cosmopolitan species; they may indeed represent a complex of related taxa, each with a geographical range more restricted than that of the species-complex itself.Abstracted from the author's Ph.D. thesis, State University of Ghent, 1982.Abstracted from the author's Ph.D. thesis, State University of Ghent, 1982. 相似文献
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16.
Microsporidia of the genus Amblyospora parasiting the adipose body of mosquito larvae of the genus Aedes and Culex has been studied with both light and electron microscopy. Six new species of microsporidia are described based on ultrastructural characteristics of spores and sporogony stages. Amblyospora flavescens sp. n. Mature spores are egg-shaped. The spore wall with three layers, about 165 nm. Exospore is two-membranous. Subexospore is absent. Endospore is electron-translucent. Polaroplast consists of three parts: lamellar, large vesicular, lamellar. The anisofilar polar filament with 10--11 coils (3 1/2 + 2 1/2 + 4-5). Fixed spores are 6.3 +/- 0.1 x 4.24 +/- 0.1 microm. Amblyospora kolarovi sp. n. Mature spores are egg-shaped. The spore wall with three layers, about 265-315 nm. Exospore shapes tucks on the surface of spore. It is two-membranous. Subexospore is quagge, structural. Endospore is electron-translucent. Polaroplast consists of two parts: lamellar and large vesicular. The anisofilar polar filament with 11-13 coils (3 + 8-10). Fixed spores are 5.4-5.6 x 3.5-4.2 microm. Amblyospora orbiculata sp. n. Mature spores are widely egg-shaped. On a back pole there is a small concavity. The spore wall with three layers, about 155 nm. Exospore is shapes tucks on a surface of spore. It is two-membranous. Subexospore is absent. Endospore is electron-translucent. Polaroplast consists of three parts: lamellar, vesicular, lamellar. Polar filament is anisofilar, with 11 1/2 coils (4 1/2 + 1 + 6). Fixed spores are 6.3 +/- 0.1 x x 4.0 +/- 0.1 microm. Amblyospora rugosa sp. n. Mature spores are egg-shaped. On a back pole there is a small concavity. The spore wall with three layers, about 225 nm. Exospore is shapes tucks on a surface of spore. It is two-membranous. Subexospore is quaggy, structural. Endospore is electron-translucent. Polaroplast lamellate. Polar filament is anisofilar, with 17 1/2 coils (3 1/2 + 1 + 13). Fixed spores are 5.3 +/- 0.1 x 3.7 +/- 0.1 microm. Amblyospora undata sp. n. Mature spores are egg-shaped. The spore wall is three-layered, about 220 nm. Exospore is shapes tucks on a surface of spore. It is two-membranous. Subexospore is quaggy, structural. Endospore is electron-translucent. Polaroplast lamellate. The anisofilar polar filament with 8 coils (3 + 5). Fixed spores are 5.0 +/- 0.1 x 3.0 +/- 0.1 microm. Amblyospora urski sp. n. Mature spores have widely oval form. The back pole is concave. The spore wall with three layers, about 280 nm. Exospore is shapes tucks on a surface of spore. It is two-membranous. Subexospore is quaggy, structural. Endospore is electron-translucent. Polaroplast lamellate. Polar filament is anisofilar, with 6 coils (2 + 4). Fixed spores are 4.4 +/- 0.1 x 2.9 +/- 0.1 microm. 相似文献
17.
T G Andreadis 《The Journal of protozoology》1990,37(3):174-182
The natural ecology of a heterosporous microsporidium, Amblyospora connecticus was investigated at three different salt marsh habitats during 1986-1989. The parasite has a well-defined seasonal transmission cycle that occurs regularly each year and intimately involves the primary mosquito host, Aedes cantator, and the intermediate copepod host, Acanthocyclops vernalis. In the spring, the microsporidium is horizontally transmitted from the copepod, where it appears to overwinter, to the mosquito via the ingestion of haploid spores produced in the copepod. Mosquitoes develop a benign infection, and females transmit the microsporidium transovarially to their progeny via infected eggs. Oviposition occurs during the summer and infected eggs hatch synchronously in the fall causing widespread epizootics. Infected larvae die, and the cycle is completed when meiospores are released into the pool and subsequently are eaten by A. vernalis, which reappears in the fall and early winter. Amblyospora connecticus thereby persists by surviving in one of two living hosts throughout most of its life cycle rather than in the extra-corporeal environment. This represents an important survival strategy for A. connecticus as results show the salt marsh habitat to be a relatively unstable environment that is subject to periodic flooding and drying. The adaptive significance of utilizing an intermediate host in the life cycle is discussed as it directly facilitates transmission and enhances survival of the microsporidium. 相似文献
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19.
Edward B. Reed 《Hydrobiologia》1986,139(2):127-133
Weekly mean lenghts of adult female Acanthocyclops robustus ranged between 1.14 and 1.41 mm in a Colorado alpine lake during the summer of 1966. The smallest animals occurred in late September and the largest in mid-August, corresponding to development in warm and cool water, respectively. The males also declined in mean length during the course of the summer and were about 70% of the length of the females on any date. About 75% of the females possessed a 3.4.4.4 spine formula; 8%, 2.3.3.3 and 17% an anomalous formula. Eight-one percent of the males had a 3.4.4.4 formula; 7%, 2.3.3.3 and 12% were anomalous. Morphological variation, and breeding experiments performed by Price (1958) suggest that A. robustus and A. vernalis as defined by Kiefer (1976) are likely species complexes, rather than just two species. 相似文献
20.
This study is the first report on the genetic characterization and relationships among different microsporidia infecting the silkworm, Bombyx mori, using inter simple sequence repeat PCR (ISSR-PCR) analysis. Six different microsporidians were distinguished through molecular DNA typing using ISSR-PCR. Thus, ISSR-PCR analysis can be a powerful tool to detect polymorphisms and identify microsporidians, which are difficult to study with microscopy because of their extremely small size. Of the 100 ISSR primers tested, only 28 primers had reproducibility and high polymorphism (93%). A total of 24 ISSR primers produced 55 unique genetic markers, which could be used to differentiate the microsporidians from each other. Among the 28 SSRs tested, the most abundant were (CA)n, (GA)n, and (GT)n repeats. The degree of band sharing was used to evaluate genetic similarity between different microsporidian isolates and to construct a phylogenetic tree using Jaccard's similarity coefficient. The results indicate that the DNA profiles based on ISSR markers can be used as diagnostic tools to identify different microsporidia with considerable accuracy. In addition, the small subunit ribosomal RNA (SSU-rRNA) sequence gene was amplified, cloned, and sequenced from each of the 6 microsporidian isolates. These sequences were compared with 20 other microsporidian SSU-rRNA sequences to develop a phylogenetic tree for the microsporidia isolated from the silkworms. This method was found to be useful in establishing the phylogenetic relationships among the different microsporidians isolated from silkworms. Of the 6 microsporidian isolates, NIK-1s revealed an SSU-rRNA gene sequence similar to Nosema bombycis, indicating that NIK-1s is similar to N. bombycis; the remaining 5 isolates, which differed from each other and from N. bombycis, were considered to be different variants belonging to the species N. bombycis. 相似文献