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1.
I. Rosario G. Soro S. Déniz O. Ferrer F. Acosta D. Padilla B. Acosta 《Mycopathologia》2010,169(4):315-319
Columba livia is an important reservoir and carrier of Cryptococcus neoformans, Cryptococcus uniguttulatus, Cryptococcus laurentii and Cryptococcus albidus. Upper digestive tract of this species is also known as a habitat for Cryptococcus neoformans. Given the increasing clinical interest of this microorganism, 331 swabs from crop and 174 dropping samples from pigeon lofts
in Grand Canary Island have been studied. The obtained results show an extensive presence samples 81 positive (24.47%) of
Cryptococcus spp. in analysed crops: 32 (9.66%) for C. neoformans, 24 (7.2%) for C. uniguttulatus, 23 (6.9%) for C. albidus and 2 (0.6%) for C. laurentii. In the same way, Cryptococcus spp was also isolated in 82 (47.13%), dropping samples: C. neoformans in 59 (33.9%), C. uniguttulatus, in 9 (5.17%), C. laurentii in 8 (4.59%) and C. albidus in 6 (3.44%) of the investigated samples, respectively. The cryptococcosis produced by species of cryptococci other than C. neoformans has become more important during the last decade, supporting the study on the role of pigeon in the epidemiology of this
disease. 相似文献
2.
Ondřej Koukol 《Mycological Progress》2010,9(3):369-378
Survey of seven strains determined as Septonema ochraceum (Dothideomycetes, inc. sed.) isolated from pine litter or obtained from public collections revealed three new species, Fusicladium cordae, F. sicilianum (Venturiaceae), Cladophialophora matsushimae (Herpotrichiellaceae) and a cryptic species morphologically identical to Devriesia americana (Teratosphaeriaceae), but phylogenetically distinct. Morphological survey and phylogenetic analysis using nucleotide sequence data from the nuclear
ribosomal subunit genes indicate a close relationship within three species colonising pine litter needles, F. cordae, F. pini and F. ramoconidii. F. sicilianum is most related to F. rhodense. C. matsushimae represents a species belonging to one of the lineages of the polyphyletic genus Cladophialophora. None of the strains observed can be classified morphologically as S. ochraceum, of which the type material does not exist. 相似文献
3.
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
4.
5.
Members of the genus Rhytidoponera and, to a lesser extent, certain Melophorus spp. are keystone mutualists for the dispersal of seeds in the southwest of Western Australia, with important ramifications
for the ecology and speciation of plants in this biodiversity hotspot. For this reason, it is important to understand the
autecology of the relevant ant species and the way in which they interact with plant seeds. This paper addresses key aspects
of the ecology of three such ant species, Rhytidoponera violacea (Forel), R. inornata Crawley and Melophorus turneri perthensis Wheeler. Data are presented on their geographic distribution, seasonality of foraging, diurnal activity, response to fire,
nest site preference, nest structure, colony size, feeding habits, foraging response to seed availability, and seedling emergence
from nests. The role of all three species as seed dispersers is confirmed, and all three species have ecologies that are well-suited
for dispersal and survival of native plant seeds. Preservation of this interaction is important for the conservation of plants,
and it is fortuitous that all three species are able to survive disturbance and return to rehabilitated areas. However, the
smaller R. inornata, and to a lesser extent, the larger R. violacea, are vulnerable to invasive ant [Pheidole megacephala (Fabricius)] incursions. M. turneri perthensis is able to coexist with the invasive ant unless this is at high densities, probably as a result of its ability to forage
during high temperatures when the invasive species is inactive. 相似文献
6.
We studied the intra- and interspecific size variability of 271 water shrewsNeomys fodiens (Pennant, 1771) andN. anomalus Cabrera, 1907 from seven sample sites along a latitudinal transect from Bosnia and Herzegovina to Poland.Neomys anomalus was the only water shrew in three Dinaride karst fields, while it was sympatric with N.fodiens in remaining sites. The first principal component scores (PC1; 72.2% of variance explained), derived from principal components
analysis of 13 cranial, mandibular and dental measurements, were used as the size factor. One-way ANOVA detected significant
interpopulation variation in both species; intraspecific variation, however, was much more pronounced inN. anomalus. No latitudinal size pattern was found in N. fodiens (r = −0.42, p = 0.58), while mean PC1 scores correlated significantly
and negatively with latitude inN. anomalus (r = −0.92, p = 0.004). Therefore, along a north to south transect,N. anomalus converged in size towards N. fodiens, which suggests that the former species occupies increasingly more aquatic habitats
in the same direction. Individuals from allopatric populations ofN. anomalus from Slovenia and Bosnia and Herzegovina were, on average, larger than sympatric conspecific populations from the same latitudinal
zone, which is consistent with the hypothesis of character displacement. 相似文献
7.
Abigail C. Ross Leila M. Porter Michael L. Power Vince Sodaro 《Primates; journal of primatology》2010,51(4):315-325
Callimico goeldii gives birth to single offspring, whereas other callitrichids, including Callithrix jacchus, twin. This study compares maternal effort and infant development in C. goeldii and C. jacchus; it is the first study to look at nursing frequency. Infants were observed from birth for 7 weeks in two captive groups each
of C. goeldii and C. jacchus. C. goeldii mothers physiologically invested the same or less than C. jacchus mothers. C. goeldii mothers gained the same amount of weight during pregnancy in absolute terms as did the smaller C. jacchus. This results in a smaller gain in proportion to maternal weight but an equivalent proportional gain on a per fetus basis.
C. goeldii mothers nursed their infants less based on duration of nursing bouts compared with C. jacchus mothers. C. goeldii mothers transported their infants exclusively through the first 2 weeks of life, which is longer than C. jacchus mothers, who exclusively transported infants only during the first week of life. As maternal infant carriage declined, other
group members transported offspring in both species. C. goeldii infants engaged in independent locomotive sequences later in development and tasted solid foods less frequently than C. jacchus infants when compared at equivalent ages. A single, opportunistic milk sample obtained from a C. goeldii mother when her infant was 48 days old indicates that C. goeldii milk contains gross energy from crude protein within the range of variation observed in Callithrix milk. Despite the similarities in milk quality and prenatal effort in individual fetuses, C. goeldii infants gain weight faster from 0 to 18 months than do C. jacchus infants. A reduction in litter size allows C. goeldii mothers to spend more time carrying their infant and to delay weaning, thereby allowing accelerated infant and juvenile growth
rates compared with C. jacchus. 相似文献
8.
Joha W. Grobbelaar Z. Wilhelm de Beer Paulette Bloomer Michael J. Wingfield Xu Dong Zhou Brenda D. Wingfield 《Mycoscience》2011,52(2):111-118
Ophiostoma species such as O. quercus are the most frequent causal agents of sapstain of freshly felled hardwood timber and pulpwood. Many species are regarded
as economically important agents of wood degradation. The aim of this study was to identify a collection of Ophiostoma isolates, resembling O. quercus, found on stained Eucalyptus pulpwood chips in China. DNA sequences of the internal transcribed spacer regions, including the 5.8S region, of the ribosomal
DNA, and parts of the β-tubulin and elongation factor-1α genes, revealed that the isolates were not O. quercus. Surprisingly, they represented O. tsotsi, a wound-infesting fungus recently described from hardwoods in Africa. In addition, sequence data from an isolate from agarwood
in Vietnam, identified in a previous study as belonging to an unknown Pesotum species, were also shown to represent O. tsotsi. A high level of genetic variability was observed among isolates of both O. quercus and O. tsotsi. This was unexpected and suggests that both species have been present in Asia for a significant amount of time. 相似文献
9.
Poor knowledge of the intraspecific variability in echolocation calls is recognized as an important limiting factor for the
accurate acoustic identification of bats. We studied the echolocation behaviors of an ecologically poorly known bat species,
Myotis macrodactylus, while they were commuting in three types of habitats differing significantly in the amount of background clutter, as well
as searching for prey above the water surface in a river. Results showed that M. macrodactylus altered their echolocation call structure in the same way during commuting as foraging bats do in relation to the changing
level of clutter. With increasing level of clutter, M. macrodactylus generally produced echolocation calls with higher start, end, and peak frequencies; wider bandwidth; and shorter pulse duration.
Compared to commuting, bats emitted significantly lower frequency calls with narrower bandwidth while searching for prey.
Discriminant function analysis indicated that 79.8% of the calls from the three commuting habitats were correctly grouped,
and 87% of the calls were correctly classified to the commuting and foraging contexts. Our finding has implications for those
who would identify species by their calls. 相似文献
10.
The intron sequence of chloroplast rpS16 and the secondary structure of its pre-mRNA were characterized for the first time in 26 Allium sativum accessions of different ecologo-geographical origins and seven related Allium species. The boundaries and main stem-loop consensus sequences were identified for all six domains of the intron. Polymorphism
was estimated for the total intron and its regions. The structural regions of the rpS16 intron proved to be heterogeneous for mutation rate and spectrum. Mutations were most abundant in domains II and IV, and
transition predominated in domains I, III, V, and VI. In addition to structural elements and motifs typical for group IIB
introns, several Allium-specific micro- and macrostructural mutations were revealed. A 290-bp deletion involving domains III and IV and part of domain
V was observed in A. altaicum, A. fistulosum, and A. schoenoprasum. Several indels and nucleotide substitutions were found to cause a deviation of the pre-mRNA secondary structure from the
consensus model of group II introns. 相似文献
11.
Cane JH 《Oecologia》2011,167(1):107-116
Pollinators, even floral generalists (=polyleges), typically specialize during individual foraging bouts, infrequently switching
between floral hosts. Such transient floral constancy restricts pollen flow, and thereby gene flow, to conspecific flowers
in mixed plant communities. Where incipient flowering species meet, however, weak cross-fertility and often similar floral
traits can yield mixed reproductive outcomes among pollinator-dependent species. In these cases, floral constancy by polyleges
sometimes serves as an ethological mating barrier. More often, their foraging infidelities instead facilitate host introgression
and hybridization. Many other bee species are oligolectic (taxonomic specialists for pollen). Oligoleges could be more discriminating
connoisseurs than polyleges when foraging among their limited set of related floral hosts. If true, greater foraging constancy
might ensue, contributing to positive assortative mating and disruptive selection, thereby facilitating speciation among their
interfertile floral hosts. To test this Connoisseur Hypothesis, nesting females of two species of oligolectic Osmia bees were presented with randomized mixed arrays of flowers of two sympatric species of their pollen host, Balsamorhiza, a genus known for hybridization. In a closely spaced grid, the females of both species preferred the larger flowered B. macrophylla, evidence for discrimination. However, both species’ females showed no floral constancy whatsoever during their individual
foraging bouts, switching randomly between species proportional to their floral preference. In a wider spaced array in which
the bouquets reflected natural plant spacing, foraging oligolectic bees often transferred pollen surrogates (fluorescent powders)
both between conspecific flowers (geitonogamy and xenogamy) and between the two Balsamorhiza species. The Connoisseur Hypothesis was therefore rejected. Foraging infidelity by these oligolectic Osmia bees will contribute to introgression and hybridization where interfertile species of Balsamorhiza meet and flower together. A literature review reveals that other plant genera whose species hybridize also attract numerous
oligolectic bees, providing independent opportunities to test the generality of this conclusion. 相似文献
12.
Jens Hellinger Klaus-Peter Hoffmann 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2009,195(9):873-879
In this study, we present evidence for the perception of different magnetic field parameters in a facultative anadromous fish
species of the family Salmonidae. Magnetic field perception of the rainbow trout, Oncorhynchus mykiss, was demonstrated with a heartbeat conditioning test. The electrocardiogram was measured with subcutaneously inserted silver
wire electrodes in freely swimming fish. We demonstrate a conditioned response (i.e. a significant longer interval between
two heartbeats) to an intensity/inclination shift for three adult and two juvenile rainbow trouts. Moreover, a conditioned
response to a 90° direction shift was demonstrated for three adult and two juvenile trouts. These findings support the hypothesis
that the rainbow trout is able to perceive different magnetic field parameters. Furthermore, the study demonstrates magnetosensation
in different developmental stages in the rainbow trout, i.e. juvenile and adult fish. 相似文献
13.
Genetic hybridization analysis was conducted with 16 natural Zygowilliopsis strains isolated in different geographical regions and maintained in collections under species names Z. californica, Hansenula dimennae, and Pichia populi. Genetic relatedness was determined on the basis of mating, viability of hybrid progeny, and meiotic recombination of markers.
Four new biological species are recognized in the former monotypic genus Zygowilliopsis. Species Z. californica and Zygowiliopsis sp. 3 probably include divergent geographical populations. It is necessary to reconsider the species composition of the genus
Zygowiliopsis and generic assignment of P. populi yeasts. Genetic and molecular identifications of the Zygowiliopsis species are in perfect agreement. 相似文献
14.
Photosynthetic rate (P
N), SPAD value, specific leaf area (SLA), flag leaf area (FLA), and nitrogen content (LN) of genus Oryza were investigated and their correlation was analyzed to assess some of the main photosynthetic traits among different species
in the genus Oryza. The results revealed wide variation in these traits. The species O. rufipogon and O. australiensis exhibited maximum photosynthetic rate. Comparison of different types of genomes (diploid: 2n=2x=24; tetraploid: 2n=4x=48)
and growth habit (shade- or sun-grown) showed the species of diploid (with genome symbol EE; 2n=2x=24) genomes, with perennial
and sun-grown species, had high apparent photosynthesis compared to others. The species with BB/BBCC, shade-grown and the
tetraploids showed high SPAD value, and the flag leaf in sun-grown species and diploids were thicker (low SLA) compared with
others. However, no significant difference could be noticed among the different types of genomes. Higher leaf area was noticed
among the species of CC/CCDD genome, perennial shade-grown species and tetraploids than in others. The variety IR 36 exhibited
highest leaf nitrogen concentration. Correlation analysis showed a strong relationship between P
N and leaf nitrogen concentration while no marked relationships were observed among other characteristics. It implies that
the species with thick and small leaves with high nitrogen concentration and high photosynthesis evolved better than others.
O. rufipogon, with the same genome as O. sativa, could be one of the wild rice resources for elite crop improvement. 相似文献
15.
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
16.
Components of the lateral line system and their innervation were studied in Odontobutis obscura (Odontobutidae) and Pterogobius elapoides (Gobiidae), which are benthic and pelagic species, respectively. Innervation of the superficial neuromasts constituting the
trunk lateral line system by way of three continuous longitudinal series (dorsal, middle, and ventral series: ld, lm, and lv series, respectively) became apparent for the first time. Innervation patterns indicated that the ld and lv series represented a mixture of displaced rows (from lm series) and new additional rows. In O. obscura, the ld and lv series were poorly developed, whereas both series were well developed in the pelagic P. elapoides, possibly as an adaptation to receive stimuli from above and below. Two extremely elongated nerve branches derived from the
lateral ramus of the posterior lateral line nerve innervated the ld and lv series, respectively, in P. elapoides. Homologies of the neuromast rows on the head and body were discussed on the basis of their innervation patterns. 相似文献
17.
Michael G. Boegle Susanne Schneider Beate Mannschreck Arnulf Melzer 《Hydrobiologia》2007,586(1):155-166
18.
Previous studies on the fourth inversion of the t complex, In17(4), suggest that loci near the center of this inversion have been subjected to segmental recombination during the past 1–2 million
years. We have used a combination of PCR-based restriction site (PBR) analysis and DNA sequencing to perform a high-resolution
analysis of a 2-million base pair (Mbp) segment in the middle of In17(4). We examined 21 restriction sites that are polymorphic between t haplotypes and their wild-type homologs, over nine distinct loci. In addition, we examined several other polymorphic sites
through DNA sequence analysis of two of these nine loci. We analyzed several haplotypes in this way, including the “complete”
t haplotypes t
w2
, t
0
, t
w32
, t
w71
, and t
w75
. We show that only t
w32
is a true “complete” t haplotype; the remaining four t haplotypes have segments of wild-type DNA ranging from less than 100 bp to 2 Mbp. The sizes of these wild-type DNA segments
are consistent with their being generated by gene-conversion events. The 2-Mbp segment is located in a region that may contain
the t-complex distorter gene Tcd2. One of the nine loci examined in this study is Fgd2, a gene that has been proposed to encode Tcd2. Sequencing and PBR data show that at least a portion of the Fgd2 gene has been converted to the wild-type within t
w71
and t
w75
mice. 相似文献
19.
Philomena Bodensteiner 《Mycological Progress》2007,6(4):221-228
Maireina afibulata and M. attenuatipilis are proposed as new members of the recently revised genus Maireina, one of the few anatomically well-studied cyphelloid groups in the Basidiomycota. Maireina species have brownish basidiomes, smooth, parietally unpigmented spores, and are characterized by non-ramified external hyphae
with more or less thick, yellow to brown cell walls and distinct crystalline incrustations that always include their distal
ends. A key to the species of the genus Maireina is presented, and M. afibulata as well as M. attenuatipilis are described and discussed in detail.
Taxonomic novelties: Maireina afibulata Bodensteiner, M. attenuatipilis Bodensteiner 相似文献
20.
We study apical dominance in Alstroemeria, a plant with an architecture very different from the model species used in research on apical dominance. The standard explant
was a rhizome with a tip and two vertically growing shoots from which the larger part had been excised leaving ca. 1 cm stem. The axillary buds that resumed growth were located at this 1-cm stem just above the rhizome. They were released
by removal of the rhizome tip and the shoot tips. Replacement of excised tips by lanolin with indole-3-butyric acid (IBA)
restored apical dominance. The auxin transport inhibitors 2,3,5-triiodobenzoic acid (TIBA) and N-1-napthylphthalamic acid (NPA) reduced apical dominance. 6-Benzylaminopurine (BAP) enhanced axillary bud outgrowth but the
highest concentrations (> 9 μM) caused fasciation. Thidiazuron (TDZ) did not show improvement relative to BAP. Even though
the architecture of Alstroemeria and the model species are very different, their hormonal mechanisms in apical dominance are for the greater part very similar. 相似文献