首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.

In Memoriam

M. R. Irwin (1897–1987) Pioneer in Immunogenetics  相似文献   

2.
3.
4.
《Journal of bryology》2013,35(2):255-264
Abstract

The differences between Thysanomitrium Schwaegr. and Campylopus Brid. are discussed and regarded as insignificant. Therefore the six Thysanomitrium species reported from South America in the Index Muscorum are critically revised. T. yunqueanum C. Müll. and T. miserum Broth. are synonyms of Campylopus richardii Brid., and T. schiffneri Broth. and T. arenaceum Broth. are placed in the genus Campylopus as new combinations. Also T. arenaceum is reported from a new locality in Brazil. No material could be found in herbaria of T. wainoi Broth. and T. gastrotis C. Müll.  相似文献   

5.
6.
7.
8.
The occurrence and contents of carotenoids in different body parts were investigated by column chromatography and TLC in Micropterus salmoides (Lalép).The following carotenoids were found: -carotene, -cryptoxanthin, -cryptoxanthin, echinenone, canthaxanthin, lutein, zeaxanthin, neothxanthin, tunaxanthin, -doradexanthin, -doradexanthin, idoxanthin, astaxanthin, astaxanthin ester, mutatochrome and mutatoxanthin.Their total contents varied within the range of 0.071–1.691 µg/g wet weight.  相似文献   

9.
The medical, veterinary and saprophytic importance ofAspergillus has been acknowledged by many authors. This paper reports on the occurrence ofAspergillus species in the air and dust of Córdoba (Spain). Four studied were done: first, on the air of three rooms and the outside area of 14 homes over 2 years; second, outdoor air in the west of the central district, with three samples daily over 1 year; third, the air inside and outside four of the largest silos and commercial grain warehouses in the province, over 1 year: and fourth, the dust of 12 primary schools in Córdoba city, for two consecutive school years. For air-sampling, volumetric and gravimetric methods were used, both with a culture medium and with 20-min exposure. For dust-sampling, a customised vacuum cleaner was used; samples collected were inoculated onto Petri dishes containing culture medium. A total of 38Aspergillus species were identified (we also detected four ascosporic states). A comparison of the results obtained at each of the sampling sites was made and an analysis of variance revealed quantitatively significant differences between sampling times.  相似文献   

10.
The genus Dahlia (Asteraceae–Coreopsideae) is monophyletic according to a recent DNA phylogeny (ETS and ITS of rDNA). Traditionally, the genus has been divided into sections, but these have been shown not to be monophyletic. We have studied variation in genome size (DNA C-values) in a sample of species to investigate the possible effects of secondary metabolites on flow cytometry and Feulgen densitometry, and to see whether genome size variation has any systematic or phylogenetic significance. Using a range of cultivars, secondary compounds from corollas were shown to have only minor effects on the Feulgen method; the floral pigments were found to be relatively inert and seemed to have been extracted on fixation with acetic methanol. Freshly expanded corollas showed apparent apoptotic DNA decay in epidermal cells, so need to be used with caution. Flow cytometric measurements with propidium iodide in some cultivars resulted in a very similar average genome size (2C = 8.62 pg) as compared with Feulgen densitometry (2C = 8.84 pg). Leaf cytosol of D. variabilis has a demonstrable inhibitory effect on propidium iodide fluorescence, which may explain some of the intraspecific variation of C-values observed. DNA 2C-values ranged from 3.30 pg in D. dissecta (2n = 34) to 9.62 pg in a D. variabilis cultivar (2n = 64). The D. variabilis cultivars had broadly similar C-values showing a 1.16-fold range between cultivars. Some of this variation probably results from technical variables and the extent of genuine variation is uncertain. The highest 2Cx-value occurred in one D. coccinea accession (2.47 pg, 2n = 32; x = 8). D. coccinea with 2n = 64 showed slightly reduced Cx-values compared to D. coccinea with 2n = 32. Artificially produced interspecific hybrids had C-values that corresponded closely with expectations from the measured values obtained from their parents.  相似文献   

11.
12.
13.
Heterodera longicolla n. sp., a member of the H. goettingiana group, is described and illustrated from roots of buffalo-grass, Buchloë dactyloides (Nutt.) Engelm., in Manhattan, Kansas. This new abullate species, having second-stage larvae with only three lines in the lateral field, is most closely related to H. cyperi Golden, Rau & Cobb, 1962, but differs particularly in having a shorter stylet in larvae, males and females; in possessing only three annules on the head of larvae and males; in having a shorter tail in larvae; and by the presence on cysts of a small anus without a circum-anal pattern.  相似文献   

14.
15.
The first part (1969) dealt with the abundance and biomass of the may-flies (Ephemeroptera). On the basis of the measurement of length of all may-flies and of the determination of the respective weight (according to the curve expressing the relation length : weight) the production for each month was calculated. The annual average for Baetis rhodani amounted to 5,317 g/m2, for Rhithrogena semicolorata 12,478 and for the species belonging to the genus Ecdyonurus 8,47 g/m2. The relation between the annual production and average annual biomass was nearly the same in all three species = 1 : 8,37. These three taxa formed 76% of the biomass. After addition of the remaining taxa of mayflies the production of Ephemeroptera in the two brooks under investigation totalled 27,152 g/m2 = 271,52 kg/ha per year.  相似文献   

16.
The authors describe a new species in the genus Schilbetrematoides Kritsky & Kulo, 1992 from the gills of Schilbe mandibularis (Günther, 1867) (Schilbeidae) caught in the rivers Bia and Agneby in Ivory Coast. S. manizani n. sp. differs from S. pseudodactylogyrus Kritsky & Kulo, 1992, a parasite of Schilbe intermedius Rüppell, 1832 by having morphologically distinct gripi.  相似文献   

17.
Protistan parasites of the genus Marteilia, phylum Paramyxea, cause the molluscs disease named Marteiliosis. Histological observations and transmission electron microscopy revealed the presence of life cycle stages of a Marteilia sp. in the bivalve mollusc Solen marginatus (Solenidae). Parasites occurred in epithelial cells of the digestive ducts and tubules. Early stages (primary cells) presented one or several nuclei while advances stages formed a complex of cells-within-cells (secondary and tertiary cells) culminating in spores. Refringent bodies were present inside the presporangia. This is the first report of a Marteilia sp. in S. marginatus.  相似文献   

18.
《Aquatic Botany》1986,24(4):321-334
The oogonium in Turbinaria conoides (J. Agardh) Kürzing at the time of release is 8-nucleate and consists of 3 wall layers namely exochiton, mesochiton and endochiton. The exochiton contains alginic acid. The mesochiton a mixture of alginic acid and sulphated polysaccharides. The endochiton that is evident in the unreleased 8-nucleate oogonium, stains for sulphated polysaccharides, but is PAS negative. In a released oogonium, the endochiton is Alcian blue and PAS positive and consists of both alginic acid and sulphated polysaccharides.Polysaccharide granules are secreted near the perinuclear region and in thecytoplasmic vacuoles during the initiation of mesochiton. Furthermore, at the distal end the mesochiton froms a pad that fuses with the exochiton. The pad consists of alternate thick and thin bands. The exochiton opens at one side due to the swelling of the oogonium and accumulation of sulphated polysaccharides between exochiton and mesochiton followed by formation and elongation of a mesochiton stalk. The 8-nucleate oogonium is, thus, extruded from the conceptacle, but remains attached to the exochiton by means of a long mesochiton stalk. The secretory paraphyses, at the time of oogonial release, produce copious amounts of polysaccharides. The oogonium is, thus, extruded through the ostiole by the combined efforts of the 3 wall layers that are histochemically and histologically different, in combination with secretion produced by secretory paraphyses.  相似文献   

19.
Anna Bothár 《Hydrobiologia》1986,140(2):97-104
Analysis of the population dynamics of Bosmina longirostris (O. F. Müller) was carried out in the River Danube in the years 1981 and 1982. An estimation method of secondary production elaborated far standing waters was adapted to river conditions. In the River Danube, compared to lakes, standing crop and production values were smaller, while fecundity, P/B values were larger and turnover time was shorter. Possible reasons for this are discussed.  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号