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We present data on the habitat, density, and spatial distribution of Rivulus giarettai, and discuss some biotic and abiotic variables related to its abundance in Free Flowing Waters (FFW) and Dam Reservoirs (DR) in palm grove (Mauritia flexuosa) marshes (Veredas) in Uberlandia, Minas Gerais, southeastern Brazil. The mean density (individuals/plot) of R. giarettai was about 13 times higher in FFW than in DR. In FFW, the density of R. giarettai was highest at intermediate amounts of substrate (plant mass) and it was positively rank-correlated with the depth, and the number of arthropods. Individuals occurred in an aggregated distribution. The aggregated pattern could be related to a concentration of individuals in microhabitats neither too much exposed nor completely saturated by plants. R. giarettai was relatively abundant and tolerant to slight man-made habitat modifications. Damming appeared to be especially problematic by negatively affecting its density.  相似文献   

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Allophycocyanin (APC) is a minor component of phycobiliproteins in cyanobacteria and red algae. This paper describes a simple and inexpensive extracting method for isolating APC from Spirulina (Arthrospira) platensis with high efficiency. The crude phycobiliprotein extract was pretreated by ammonium sulfate fractionation. Then, by adding hydroxylapatite into crude phycobiliprotein extract dissolved in 20 mM phosphate buffer (pH 7.0), APC was selectively adsorbed by hydroxylapatite but C-phycocyanin (C-PC) was not. The hydroxylapatite was collected and APC was extracted from the crude phycobiliprotein extract. Then, the enriched APC was washed off from the hydroxylapatite using 100 mM phosphate buffer (pH 7.0). In this simple extracting method it was easy to remove C-PC and isolate APC in large amounts. The absorbance ratio A 650/A 280 of extracted APC reached 2.0. The recovery yield was 70%, representing 4.61 mg · g−1 wet weight. The extracted APC could be further purified by a simple anion-exchange chromatography with a pH gradient from 5.6 to 4.0. The absorbance ratio A 650/A 280 of the purified APC reached 5.0, and the overall recovery yield was 43%, representing 2.83 mg · g−1 wet weight. Its purity was confirmed by native polyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulfate-PAGE.  相似文献   

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Cryopreservation of Robinia pseudoacacia explants by vitrification achieved 78% survival following the stepwise preculture of shoot tips in (0.3 + 0.5 + 0.7 M) sucrose with a 80 min incubation in PVS2; compared to 87% survival after desiccation of explants to 30% water content, following 3 days alginate bead (with glycerol and sucrose treatments) preculture in 0.7 M sucrose.  相似文献   

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The temnodontis variety of Caligus mauritanicus Brian, 1924 described by Brian (1924) is a valid species known only from a single host species, Pomatomus saltatrix (Linnaeus). New material of this species has been examined from the same host fish caught from Abuqir Bay, Alexandria (Egypt), from Iskenderun Bay (Turkey) and from off the coast of South Africa. Using this material, C. temnodontis Brian, 1924 is redescribed and compared with related species. It is most closely related to the Indo-Pacific species C. pagrosomi Yamaguti, 1939.  相似文献   

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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   

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SPARC is a matricellular protein, which, along with other extracellular matrix components including collagens, is commonly over-expressed in fibrotic diseases. The purpose of this study was to examine whether inhibition of SPARC can regulate collagen expression in vitro and in vivo, and subsequently attenuate fibrotic stimulation by bleomycin in mouse skin and lungs.  相似文献   

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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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Arachis correntina (Burkart) Krapov. & W.C. Gregory is a herbaceous perennial leguminous plant growing in the Northeast of the Province Corrientes, Argentina. It is important as forage. The development of new A. correntina cultivars with improved traits could be facilitated through the application of biotechnological strategies. The purpose of this study was to investigate the plant regeneration potential of mature leaves of A. correntina in tissue culture. Buds were induced from both petiole and laminae on 0.7% agar-solidified medium containing 3% sucrose, salts and vitamins from Murashige and Skoog (MS) supplemented with 0.5–25 M thidiazuron (TDZ). Shoot induction was achieved by transference of calli with buds to MS supplemented with 5 M TDZ. Fifty-four percent of the regenerated shoot rooted on MS + 5 M naphthaleneacetic acid. Histological studies revealed that shoots regenerated via organogenesis.  相似文献   

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Summary  The name Pavetta modesta (Hiern) S. E. Dawson is a later homonym of P. modesta Bremek. Pavetta crystalensis is proposed as a new name.  相似文献   

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ALBINO3, a homologue of PPF1 in Arabidopsis, encodes a chloroplast protein, and is essential for chloroplast differentiation. In the present study, ALBINO3(−) transgenic plants exhibited a significant decrease in both the number of rosette leaves at bolting and the days before bolting, suggesting the important roles of ALBINO3 in regulating flowering during non-inductive short-day photoperiods. ALBINO3 mRNA was apparently accumulated in shoot apical meristem and floral meristems around the shoot apical meristem in wild-type plants. ALBINO3 might be predominantly involved in inducing the floral repression pathway by activating the expression of TFL1, and by suppressing the expression of LFY, respectively, in the shoot apical meristem. Moreover, the function of ALBINO3 in regulating flowering transition depended on the expression of CO and GA1, because ALBINO3 might function in the downstream integration of the photoperiod-dependent and the photoperiod-independent pathways. These results suggest that ALBINO3 may have an important integrative function in the flowering process in Arabidopsis.  相似文献   

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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   

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The anal sacs of Thalassema thalassemum consist of an elongate tubular invagination (end sac) that is uniformly covered with numerous sessile ciliated funnels. While the funnels are composed of multi-ciliated, non-muscular cells and possess a ciliated neck-like constriction, the end sacs are lined by a simple epithelium of large, irregularly formed and sparsely ciliated cells that include masses of secretory granules. Podocytes are incorporated in the peritoneum that surrounds the anal sacs. A muscle grid consisting of inner longitudinal, outer circular and additional diagonal fibres that branch off of the circular fibres is embedded in the matrix between the end sac epithelium and peritoneum. Major structural differences between the hindgut and anal sacs support the hypothesis that the anal sacs are not gut derivatives but are instead part of a modified metanephridial system. Comparison of the anal sac morphology in Echiura reveals that T. thalassemum shares a tubular end sac with all known members of Thalassematinae and Ikedaidae, as well as with some members of Bonelliidae and Echiurinae, while the sessile funnels are apomorphic for the Thalassematinae.  相似文献   

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