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1.
We assessed information on the population structure of the nurse shark, Ginglymostoma cirratum, at Atol das Rocas, northeastern Brazil, through underwater observations. Based on photographic records of natural distinctive marks for individual recognition, we used probabilistic estimators (Petersen–Bailey and Jolly–Seber) to assess population size. We found that 46% of the sharks (194 individuals) had distinctive marks. The population size was estimated in 368 individuals, using the Petersen–Bailey estimator, and 339 individuals using the Jolly–Seber estimator.  相似文献   

2.
Synopsis Studies of feeding in bony fishes have almost universally demonstrated the ability of individuals to modulate their method of capture in response to differing stimuli. Preliminary evidence indicates that morphologically specialized inertial suction feeding sharks are the most likely fishes to lack inherent modulatory ability. We examined the ability of the nurse shark, Ginglymostoma cirratum, to modulate its feeding behavior based on different food types and sizes. G. cirratum is an inertial suction feeding fish that is apparently stereotyped in its food capture behavior. Electromyography showed no statistical difference between feeding motor patterns based on food type (squid or fish) or size (gape width or twice gape width), although there were slight inter-individual differences in the onset of muscle firing for some muscles. Kinematic analysis showed a statistical difference in variables associated with durations for different food types, with the durations for all variables being faster for squid bites than fish bites, but no difference based on the size of the food item. This apparent lack of modulation may be associated with specialization of the morphology and behavior of G. cirratum for obligate suction prey capture. This functional specialization constrains the method in which G. cirratum captures prey but does not appear to result in dietary specialization. An unusual post capture spit-suck manipulation allows this shark to handle and ingest large prey.  相似文献   

3.
Summary   Funastrum rupicola Goyder, a new species of Apocynaceae: Asclepiadoideae from Bolivia, is described and illustrated. The conservation status of this species is assessed.  相似文献   

4.
Summary   Linaria khalkhalensis Hamdi & Assadi is described as a new species from Azerbaijan and Guilan provinces (northern Iran), belonging to Linaria sect. Linaria. It is close to Linaria lineolata Boiss. and L. elymaitica (Boiss.) Kuprian., which it resembles in habit and vegetative features. However, floral and seed characters together with a distinctive geographical distribution, warrant recognition at the species rank. An illustration of the new species, a distribution map, scanning electron micrographs of seed and capsule surfaces, and an identification key are also included.  相似文献   

5.
Summary   Typhonium stigmatilobatum V. D. Nguyen, a new species from Vietnam, is described and illustrated.  相似文献   

6.
A revision of Penstemon sect. Saccanthera subsect. Serrulati includes a new species (P. salmonensis), a new variety (P. triphyllus var. infernalis), and the elevation of a subspecies to species (P. curtiflorus), bringing the total number of species to eight, which are keyed and described, complete with nomenclature and type citations.  相似文献   

7.
Two repeated DNA sequences isolated from a partial genomic DNA library of Helianthus annuus, p HaS13 and p HaS211, were shown to represent portions of the int gene of a Ty3 /gypsy retroelement and of the RNase-Hgene of a Ty1 /copia retroelement, respectively. Southern blotting patterns obtained by hybridizing the two probes to BglII- or DraI-digested genomic DNA from different Helianthus species showed p HaS13 and p HaS211 were parts of dispersed repeats at least 8 and 7 kb in length, respectively, that were conserved in all species studied. Comparable hybridization patterns were obtained in all species with p HaS13. By contrast, the patterns obtained by hybridizing p HaS211 clearly differentiated annual species from perennials. The frequencies of p HaS13- and p HaS211-related sequences in different species were 4.3x10(4)-1.3x10(5) copies and 9.9x10(2)-8.1x10(3) copies per picogram of DNA, respectively. The frequency of p HaS13-related sequences varied widely within annual species, while no significant difference was observed among perennial species. Conversely, the frequency variation of p HaS211-related sequences was as large within annual species as within perennials. Sequences of both families were found to be dispersed along the length of all chromosomes in all species studied. However, Ty3 /gypsy-like sequences were localized preferentially at the centromeric regions, whereas Ty1/ copia-like sequences were less represented or absent around the centromeres and plentiful at the chromosome ends. These findings suggest that the two sequence families played a role in Helianthusgenome evolution and species divergence, evolved independently in the same genomic backgrounds and in annual or perennial species, and acquired different possible functions in the host genomes.  相似文献   

8.
New combinations are proposed in anticipation of the Polygonaceae treatment in the forthcoming volume of Intermountain Flora: Polygonum kelloggii var. esotericum, P. kelloggii var. watsonii , Rumex densiflorus var. pycnanthus , R. salicifolius var. utahensis, and R. occidentalis var. tomentellus. Typifications are proposed to facilitate ongoing studies in Polygonaceae and to maintain current usage.  相似文献   

9.
Summary  A new and probably endemic species of Cambessedesia DC. is described from campo rupestre vegetation, as part of a floristic survey of Melastomataceae from the S?o José mountain range, Tiradentes District, Minas Gerais State, Brazil. Miscellaneous  Accepted for publication April 2008.  相似文献   

10.
Elaphoglossum mickeliorum, a new species from the eastern slopes of the Peruvian Andes, is here described and illustrated. It belongs to E. sect. Polytrichia, which is characterized by the presence of subulate scales and absence of hydathodes on the sterile leaves of adult sporophytes. Herbarium specimens of this new species were first collected by Alwyn H. Gentry ca. 40 years ago, but these got readily confused with E. erinaceum and went undescribed since then. The new species differs from members of the E. erinaceum complex by having a nearly continuous band of planar, nonsubulate scales along the laminar margins of sterile leaves. Based on this character, E. mickeliorum resembles species such as E. glaziovii, E. ornatum, and E. scolopendrifolium. It differs from these by the presence of minute glandular hairs on petioles and costae. A distribution map and a figure with line drawings are also provided. For comparative purposes, the line drawing includes E. blepharoglottis, which is here illustrated for the first time.  相似文献   

11.
A genetic transformation system has been developed for callus cells of Crataegus aronia using Agrobacterium tumefaciens. Callus culture was established from internodal stem segments incubated on Murashige and Skoog (MS) medium supplemented with 5 mg l−1 Indole-3-butyric acid (IBA) and 0.5 mg l−1 6-benzyladenine (BA). In order to optimize the callus culture system with respect to callus growth and coloration, different types and concentrations of plant growth regulators were tested. Results indicated that the best average fresh weight of red colored callus was obtained on MS medium supplemented with 2 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.5 mg l−1 kinetin (Kin) (callus maintenance medium). Callus cells were co-cultivated with Agrobacterium harboring the binary plasmid pCAMBIA1302 carrying the mgfp5 and hygromycin phosphotransferase (hptII) genes conferring green fluorescent protein (GFP) activity and hygromycin resistance, respectively. Putative transgenic calli were obtained 4 weeks after incubation of the co-cultivated explants onto maintenance medium supplemented with 50 mg l−1 hygromycin. Molecular analysis confirmed the integration of the transgenes in transformed callus. To our knowledge, this is the first time to report an Agrobacterium-mediated transformation system in Crataegus aronia.  相似文献   

12.
Summary   Bulbophyllum fendlerianum is newly described based on a collection of August Fendler in Venezuela, deposited at the Royal Botanic Gardens, Kew. It was previously confused with B. manarae, but differs significantly from the latter species in its petal and lip shape, particularly the callus.  相似文献   

13.
Studying Pneumocystis has proven to be a challenge from the perspective of propagating a significant amount of the pathogen in a facile manner. The study of several fungal pathogens has been aided by the use of invertebrate model hosts. Our efforts to infect the invertebrate larvae Galleria mellonella with Pneumocystis proved futile since P. murina neither caused disease nor was able to proliferate within G. mellonella. It did, however, show that the pathogen could be rapidly cleared from the host.  相似文献   

14.
15.
Ogataea parapolymorpha sp. n. (NRRL YB-1982, CBS 12304, type strain), the ascosporic state of Candida parapolymorpha, is described. The species appears homothallic, assimilates methanol as is typical of most Ogataea species and forms hat-shaped ascospores in asci that become deliquescent. O. parapolymorpha is closely related to Ogataea angusta and Ogataea polymorpha. The three species can be resolved from gene sequence analyses but are unresolved from fermentation and growth reactions that are typically used for yeast identification. On the basis of multiple isolates, O. angusta is known only from California, USA, in association with Drosophila and Aulacigaster flies, O. parapolymorpha is predominantly associated with insect frass from trees in the eastern USA but O. polymorpha has been isolated from various substrates in the USA, Brazil, Spain and Costa Rica.  相似文献   

16.
Recently, the prenyltransferase SirD was found to be responsible for the O-prenylation of tyrosine in the biosynthesis of sirodesmin PL in Leptosphaeria maculans. In this study, the behavior of SirD towards phenylalanine/tyrosine and tryptophan derivatives was investigated. Product formation has been observed with 12 of 19 phenylalanine/tyrosine derivatives. It was shown that the alanine structure attached to the benzene ring and an electron donor, e.g., OH or NH2, at its para-position are essential for the enzyme activity. Modifications were possible both at the side chain and the benzene ring. Enzyme products from seven phenylalanine/tyrosine derivatives were isolated and characterized by MS and NMR analyses including HSQC and HMBC and proven to be O- or N-prenylated derivatives at position C4 of the benzene rings. K M values of six selected derivatives were found in the range of 0.10–0.68 mM. Catalytic efficiencies (K cat/K M ) were determined in the range of 430–1,110 s−1·M−1 with l-tyrosine as the best substrate. In addition, 7 of 14 tested tryptophan analogs were also accepted by SirD and converted to C7-prenylated derivatives, which was confirmed by comparison with products obtained from enzyme assays using a 7-dimethylallyltryptophan synthase 7-DMATS from Aspergillus fumigatus.  相似文献   

17.
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   

18.
Here we evaluate the origins and relationships of Mexican and Central American Diplazium hybrids derived from crosses involving either D. plantaginifolium or D. ternatum. Based on study of live plants and herbarium specimens, we distinguish D. ×verapax from the similar D. riedelianum and present evidence that the former is a sterile hybrid derived from a cross between D. plantaginifolium and D. werckleanum. We also describe new hybrids, D. ×torresianum and D. ×subternatum from Mexico and northern Central America. Both involve D. ternatum as one parent. Diplazium. cristatum is the other putative parent of D. ×torresianum, and D. plantaginifolium is the second parent of D. ×subternatum. We also designate lectotypes for D. cordovense and D. dissimile.  相似文献   

19.

Background

Gonadotropin releasing hormone (GnRH) is responsible for stimulation of gonadotropic hormone (GtH) in the hypothalamus-pituitary-gonadal axis (HPG). The regulatory mechanisms responsible for brain specificity make the promoter attractive for in silico analysis and reporter gene studies in zebrafish (Danio rerio).

Results

We have characterized a zebrafish [Trp7, Leu8] or salmon (s) GnRH variant, gnrh 3. The gene includes a 1.6 Kb upstream regulatory region and displays the conserved structure of 4 exons and 3 introns, as seen in other species. An in silico defined enhancer at -976 in the zebrafish promoter, containing adjacent binding sites for Oct-1, CREB and Sp1, was predicted in 2 mammalian and 5 teleost GnRH promoters. Reporter gene studies confirmed the importance of this enhancer for cell specific expression in zebrafish. Interestingly the promoter of human GnRH-I, known as mammalian GnRH (mGnRH), was shown capable of driving cell specific reporter gene expression in transgenic zebrafish.

Conclusions

The characterized zebrafish Gnrh3 decapeptide exhibits complete homology to the Atlantic salmon (Salmo salar) GnRH-III variant. In silico analysis of mammalian and teleost GnRH promoters revealed a conserved enhancer possessing binding sites for Oct-1, CREB and Sp1. Transgenic and transient reporter gene expression in zebrafish larvae, confirmed the importance of the in silico defined zebrafish enhancer at -976. The capability of the human GnRH-I promoter of directing cell specific reporter gene expression in zebrafish supports orthology between GnRH-I and GnRH-III.
  相似文献   

20.
Summary  A new monotypic bamboo genus Phuphanochloa (Poaceae: Bambusoideae) from north-eastern Thailand is described, together with a new species, P. speciosa.  相似文献   

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