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1.
A study of airborneAlternaria spores was carried out over the period from April 1992 to October 1993, in the Rehabilitation Medical Centre of Montescano
(PV), using an automatic volumetric spore trap (VPPS 2000 Lanzoni). The evaluation of the air concentration of these spores
is becoming ever more important as it is this mycophyte which is the commonest cause of a positive allergy test. In 1993 the
concentration ofAlternaria spores was much higher than in the previous year and the period of highest sporulation was different, depending on the different
rainfall pattern of the 2 years. 相似文献
2.
Summary The first observations from Huelva (southwestern Iberian Peninsula) on the phenology of Ash, based on an aeropalynological study over three years, are presented. Sampling was carried out with a Cour trap. The beginning of pollination is related to the moment of the lowest average temperature of the year, usually in January. Flowering occurs earlier if there are exceptionally low average temperatures (<10°C) in November. The amount of rainfall in autumn and winter affects the intensity of pollination. 相似文献
3.
Spore formation in the Actinoplanaceae (Actinomycetales) 总被引:1,自引:0,他引:1
Spore development in four genera, Actinoplanes, Dactylosporangium, Planomonospora, and Streptosporangium, was studied by transmission and scanning electron microscopy. Actinoplanes and Streptosporangium formed spores by fragmentation of a hypha within its expanded outer sheath, as do many other actinomycetes. Dactylosporangium and Planomonospora formed spores endogenously by development of wall material within the parent hypha. In this respect, they resembled the genera Actinobifida and Thermoactinomyces. The term sporangium has therefore been used to describe structures which are not homologous. It was suggested that the term should be confined to structures in which endogenous spore formation occurs. 相似文献
4.
The new familyStephanosporaceae (Basidiomycetes, Fungi) is proposed. As far as known, the range of the family covers aphyllophoroid (Lindtneria) and gastroid genera (Stephanospora) which are characterized by strongly sculptured and coloured spores. From the micro- and ultrastructural point of viewLindtneria andStephanospora are practically undistinguishable. Therefore, the two genera are considered to be closely related, despite their striking differences concerning the macromorphology of their carpophores. 相似文献
5.
Three important phytopathogenic spores which cause serious fungal diseases on vines (Botrytis, Uncinula andPlasmopara) were monitored from June 2, 1994 to September 21, 1994, in vineyards belonging to ‘Estación de Enoloxía e Viticultura’ of
Ponte San Clodio-Leiro (Ourense), one of the most important vine growing areas of northwest of Spain. The concentrations for
each of the genera were correlated with rainfall, humidity, maximum, minimum and average temperatures. These meteorological
parameters are currently used to determine chemical sprays to be applied to the vines. The aim was to establish the behaviour
of airborne concentrations of spores of these taxa during the period from the flowering to harvest because these are the periods
of greatest susceptibility to attack by these pathogens. 相似文献
6.
Phylogenetic relationships of the genera Russula and Lactarius were investigated using sequence data from the nuclear-encoded large subunit ribosomal DNA (LSU rDNA). Ninety-five sequences belonging to the genera Russula and Lactarius, including 31 sequences from the databases, were used in this study. Analysis of the LSU rDNA region indicated that Russulaceae was divided into six groups (group A–F) in the neighbor-joining (NJ) tree. Lactarius consisted of one large clade (group A). Therefore, this genus was found to be monophyletic. However, the monophyly of genus Russula remained unclear. The genus Russula consisted of five groups in the NJ tree. Group B includes sects. Plorantes and Archaeinae (Heim), and group C includes sects. Delicoarchaeae and Russula in the NJ tree. Neither of the two groups formed a single clade in the most parsimonius (MP) tree. Group D includes many taxa having colored spore prints and amyloid in suprahilar plage of spores in sect. Russula and sect. Rigidae. Group E consists of only sect. Compactae and is further divided into three subclades, represented by R. densifolia, R. nigricans, and R. subnigricans, respectively. Group F contains sects. Rigidae, Ingratae, and Pelliculariae. Sect. Compactae and sect. Plorantes should not be as closely related as previously supposed. Russula earlei may be placed in sect. Archaeinae Heim. Russula flavida (subsect. Amoeninae) is placed in sect. Russula with R. aurea with a high bootstrap value (99%). The nuclear LSU rDNA region is a useful tool in recognization of species of Russulaceae and may provide information concerning phylogenetic relationships between the genera Russula and Lactarius. 相似文献
7.
8.
Paired exocrine metapleural glands are present in almost all ants and produce compounds with antibiotic properties towards
a variety of pathogenic fungi and bacteria. In Acromyrmex leaf-cutting ants, small workers have relatively large metapleural glands compared to large workers, and thus harbour approximately
half the number of gland cells of large workers, despite being only one-fifteenth their body mass. Here we present results
showing that when the two worker castes of A. echinatior are treated with spores of the pathogenic fungus Aspergillus nomius in doses that correspond to the difference in metapleural gland cell numbers they do not differ in survival. However, we
also show, for the first time, that small workers survive significantly longer than large workers when both are challenged
with a dose of spores that corresponds to their difference in body mass. Furthermore, the time until Aspergillus nomius hyphae and spores appear on the cadavers of workers dead from infection, is significantly increased in the small worker caste.
In addition to supporting previous findings that the metapleural glands have an important defence function, the results of
this study indicate that the relatively large glands in small workers makes this caste particularly well adapted to preventing
pathogenic microorganisms from entering the colony.
Received 23 January 2006; revised 7 April 2006; accepted 11 April 2006. 相似文献
9.
10.
Baweja RB Zaman MS Mattoo AR Sharma K Tripathi V Aggarwal A Dubey GP Kurupati RK Ganguli M Chaudhury NK Sen S Das TK Gade WN Singh Y 《Archives of microbiology》2008,189(1):71-79
Bacillus anthracis makes highly stable, heat-resistant spores which remain viable for decades. Effect of various stress conditions on sporulation
in B. anthracis was studied in nutrient-deprived and sporulation medium adjusted to various pH and temperatures. The results revealed that
sporulation efficiency was dependent on conditions prevailing during sporulation. Sporulation occurred earlier in culture
sporulating at alkaline pH or in PBS than control. Spores formed in PBS were highly sensitive towards spore denaturants whereas,
those formed at 45°C were highly resistant. The decimal reduction time (D-10 time) of the spores formed at 45°C by wet heat,
2 M HCl, 2 M NaOH and 2 M H2O2 was higher than the respective D-10 time for the spores formed in PBS. The dipicolinic acid (DPA) content and germination
efficiency was highest in spores formed at 45°C. Since DPA is related to spore sensitivity towards heat and chemicals, the
increased DPA content of spores prepared at 45°C may be responsible for increased resistance to wet heat and other denaturants.
The size of spores formed at 45°C was smallest amongst all. The study reveals that temperature, pH and nutrient availability
during sporulation affect properties of B. anthracis spores. 相似文献
11.
The exposure to spores causing health effects is usually assessed by determining the concentration of viable spores per cubic
meter of air (CFU/m3).Since allergens might also be present in dead spores or smaller particles, the objective of this study was to investigate
the correlation between the viable spores of Alternaria and Cladosporium at different indoor and outdoor sites and the corresponding allergen concentration detected with a specially developed ELISA
(Enzyme Linked Immunosorbent Assay). In outdoor air, the results show a strong correlation between the different sampling
techniques applied for viable spores (Slit-Sampler and Multistage Liquid Impinger) and between the viable spores and the allergen
concentrations detected in the liquid samples of the impingers. Indoors, the number of viable spores and the allergen concentration
do not correlate and the allergen load is underestimated if colony counting methods are used.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
12.
The work was carried out using a Cour trap that sampled the air of the city for 8 consecutive years (1987–1994). The pollen
ofPlatanus hispanica is the fourth most abundant in the air of Seville (a mean of 11.05% of the total pollen collected). The variation throughout
the years in the sum of weekly concentrations ofPlatanus hispanica pollen presents a certain biennial rhythm, in which years of high and low collection of pollen alternate. The starting day
of the main pollination period (MPP) is negatively related with the mean of the mean temperatures for February (r=0.73,r
2=0.53,P=0.0398) and is earlier (at the beginning of March) when the mean temperature for February is high, and vice versa. The pattern
of pollen variation inPlatanus hispanica remains constant through the years—pollen appears abruptly in high weekly concentrations (> 150 grains/m3) in March (sporadically at the beginning of April), with a week of maximum pollen emission (WMPE) in which more than 50%
of the annual pollen is collected (in 6 of the 8 years), and a main pollination period (MPP) of 2 or 3 weeks (except in 1989
when it was 5 weeks). In every year (except 1989), weekly mean temperatures increased during the MPP, the duration of which
depends on mean temperature and mean rainfall: mean temperatures > 16°C and absence of rainfall shorten the MPP, while lower
temperatures and presence of rainfall lengthen it. The meteorological conditions most often found during the WMPE are mean
temperatures > 15°C and rainfall absent or almost so. 相似文献
13.
Vesicular-arbuscular (VA) mycorrhizal fungi in pure patches of coastal dune plantsElymus mollis, Wedelia prostrata andZoysia macrostachya were examined for frequency of occurrence and number of spores of VA mycorrhizal fungi over one year. Six species in three genera of VA mycorrhizal fungi were recovered. Under a patch ofE. mollis, spores ofAcaulospora sp. 1,Glomus tortuosum, Glomus sp. 1,Glomus sp. 2 andScutellospora gregaria were recovered. Spores ofGlomus spp. were most common. In patches ofW. prostrata andZ. macrostachya spores ofAcaulospora sp. 1,G. tortuosum, Glomus sp. 1,Glomus sp. 2,S. gregaria andScutellospora sp. 1 were found.Contribution No. 112, Laboratories of Plant Pathology and Mycology, Institute of Agriculture and Forestry, University of Tsukuba. 相似文献
14.
Othmar Breuß 《Plant Systematics and Evolution》1985,148(3-4):313-315
Verrucaria schaereri (Fr.)Nyl. is accorded generic status asPlacocarpus
Trev. emend.O. Breuss. The main differences between the two genera concern the thallus anatomy and the spores which are halonate inPlacocarpus. The following new combinations are proposed:Placocarpus schaereri (Fr.)O. Breuss andPlacidiopsis cinerascens (Nyl.)O. Breuss. 相似文献
15.
Guillou L Eikrem W Chrétiennot-Dinet MJ Le Gall F Massana R Romari K Pedrós-Alió C Vaulot D 《Protist》2004,155(2):193-214
Picoplanktonic prasinophytes are well represented in culture collections and marine samples. In order to better characterize this ecologically important group, we compared the phylogenetic diversity of picoplanktonic prasinophyte strains available at the Roscoff Culture Collection (RCC) and that of nuclear SSU rDNA sequences from environmental clone libraries obtained from oceanic and coastal ecosystems. Among the 570 strains avalaible, 91 belonged to prasinophytes, 65 were partially sequenced, and we obtained the entire SSU rDNA sequence for a selection of 14 strains. Within the 18 available environmental clone libraries, the prasinophytes accounted for 12% of the total number of clones retrieved (142 partial sequences in total), and we selected 9 clones to obtain entire SSU rDNA sequence. Using this approach, we obtained a subsequent genetic database that revealed the presence of seven independent lineages among prasinophytes, including a novel clade (clade VII). This new clade groups the genus Picocystis, two unidentified coccoid strains, and 4 environmental sequences. For each of these seven lineages, at least one representative is available in culture. The three picoplanktonic genera Ostreococcus, Micromonas, and Bathycoccus (order Mamiellales), were the best represented prasinophytes both in cultures and genetic libraries. SSU rDNA phylogenetic analyses suggest that the genus Bathycoccus forms a very homogeneous group. In contrast, the genera Micromonas and Ostreococcus turned out to be quite complex, consisting of three and four independent lineages, respectively. This report of the overall diversity of picoeukaryotic prasinophytes reveals a group of ecologically important and diverse marine microorganims that are well represented by isolated cultures. 相似文献
16.
A low-cost, low-maintenance system for soilless production of vesicular-arbuscular mycorrhizal (VAM) fungus spores and inoculum was developed and adapted for production of acidophilic and basophilic isolates. Corn (Zea mays) plants were grown with Glomus etunicatum, G. mosseae or Gigaspora margarita in sand automatically irrigated with modified Hoagland's solution. Sand particle size, irrigation frequency, P concentration, and buffer constituents were adjusted to maximize spore production. Modified half-strength Hoagland's solution buffered with 4-morpholine ethane-sulfonic acid (MES) automatically applied 5 times/day resulted in production of 235 G. etunicatum spores/g dry wt. of medium (341000 spores/pot) and 44 G. margarita spores/g dry wt. of medium (64800 spores/pot). For six basophilic isolates of G. mosseae, CaCO3 was incorporated into the sand and pots were supplied with the same nutrient solution as for acidophilic isolates. The increased pH from 6.1±0.2 to 7.2±0.2 resulted in spore production ranging from 70 to 145 spores/g dry wt. (102000–210000 spores/pot). Spore production by all isolates grown in the soilless sand system at Beltsville has exceeded that of traditional soil mixtures by 32–362% in 8–12 weeks. 相似文献
17.
Summary The sporulation and toxicity of Bacillus thuringiensis H14 were studied as a function of aeration. The fed-batch cultures carried out in the similar aeration conditions were followed
in four different oxygen transfer rates containing 0, 20, 100 and 250 mmol/l/h. The percentage of total cells which had formed
refractile spores in these four oxygen transfer rates were 100, 93, 84 and 48%, respectively. The highest rate of sporulation
was observed in the absence of oxygen and the mature spores were the only population present under this condition at the end
of culture. Sporulation in a large portion of cells failed under saturated oxygenation and either mature spores or vegetative
cells were present at the end of culture. In the intermediate conditions, cells in different physiological states could be
observed at the end of culture. It was found that the optimal conditions for spore yield and for δ-endotoxin yield were not
the same, even though sporulation and δ-endotoxin formation proceed simultaneously during the fermentation process. The 130-kDa
δ-endotoxin seemed to be more sensitive to aeration conditions. The higher toxicity against Culex pipiens was obtained under the saturated condition. 相似文献
18.
M. Bigazzi 《Plant Systematics and Evolution》1989,163(1-2):1-12
TEM observations were carried out on 40 taxa of the familyVerbenaceae and 35 taxa of the familyOleaceae, in order to ascertain distribution, ultrastructure and morphology of the intranuclear proteinic inclusions in the mesophyll parenchymatic cells. The investigated genera amount to some 25% and 60% respectively of the genera of the two families. Inside theVerbenaceae, lamellar inclusions (L-type) occur in 6 out of 23 investigated genera: they are mostly present inside the tribesCitharexyleae andVerbeneae (both belonging toVerbenoideae), while they are absent in other subfamilies. All of the investigatedOleaceae genera show intranuclear crystalline inclusions (C 1-type) of three different shapes. Among theAsteridae this is a character peculiar toOleaceae. They appear to be a well defined natural group, including the controversial genusNyctanthes. 相似文献
19.
The effect of agricultural practices on the development of indigenous arbuscular mycorrhizal fungi. I. Field studies in an Indonesian ultisol 总被引:1,自引:1,他引:0
Two pre-established agricultural field trials were assessed for the abundance of arbuscular mycorrhizal fungi (AMF) in the
soil (density of spores, species richness and lengths of extra-radical mycelium [ERM]) in association with one of three tropical
plant species (Gliricidia sepium, Peltophorum dasyrachis and Zea mays). The trials were managed by one of three agricultural practices: soil disturbance in a monoculture system, a root barrier
to prevent interactions between plants in an agroforestry system or the addition of organic matter (OM) in an agroforestry
and a monoculture system. The lengths of ERM of AMF in the soil were greater in the agroforestry system than the monoculture
system. These were greater when a root barrier was present, but decreased when OM was added. Soil disturbance reduced the
density of spores, species richness and the lengths of ERM of AMF compared with the undisturbed soil. This work indicates
that agricultural trials may provide a useful tool to monitor the abundance of AMF in the field. Clearly, there is potential
to increase the abundance of AMF, from different genera, in the soil through the management of agricultural practices. The
significance of the abundance of AMF for subsequent benefits to plant growth and development and ultimately the sustainability
of tropical agro-ecosystems are discussed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
20.
Erich Kessler 《Archives of microbiology》1980,126(1):11-14
The 17 Ankistrodesmus strains studied do not produce extracellular amylolytic enzymes. 20 out of 28 Scenedesmus strains, however, are able to hydrolyse starch.The groups of strains previously characterized physiologically and biochemically were assigned to established species of the genera Ankistrodesmus (including Monoraphidium) and Scenedesmus.Abbreviation GC
Guanine + cytosine 相似文献