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1.
The re-emergence of Gymnodinum catenatum blooms after a 10 year hiatus of absence initiated the present investigation. This study aims to evaluate the exposure of
small pelagic fishes to paralytic shellfish toxins (PST) during blooms of G. catenatum. Sardines (Sardina pilchardus) were selected as a representative fish species. In order to assess toxin availability to fish, both intracellular PSTs (toxin
retained within the algal cells) and extracellular PSTs (toxin found in seawater outside algal cells) were quantified, as
well as toxin levels within three fish tissue matrices (viscera, muscle and brain). During the study period, the highest cell
densities of G. catenatum reached 2.5 × 104 cells l−1 and intracellular PST levels ranged from 3.4 to 398 ng STXeq l−1 as detected via an enzyme linked immunosorbent assay (ELISA). Measurable extracellular PSTs were also detected in seawater
(0.2–1.1 μg STXeq l−1) for the first time in Atlantic waters. The PST profile in G. catenatum was determined via high performance liquid chromatography with fluorescence detection (HPLC-FLD) and consisted mostly of
sulfocarbamoyl (C1+2, B1) and decarbamoyl (dcSTX, dcGTX2+3, dcNEO) toxins. The observed profile was similar to that reported
previously in G. catenatum blooms in this region before the 10-year hiatus. Sardines, planktivorous fish that ingest a large number of phytoplankton
cells, were found to contain PSTs in the viscera, reaching a maximum of 531 μg STXeq kg−1. PSTs were not detected in corresponding muscle or brain tissues. The PST profile characterized in sardine samples consisted
of the same sulfocarbamoyl and decarbamoyl toxins found in the algal prey with minor differences in relative abundance of
each toxin. Overall, the data suggest that significant biotransformation of PSTs does not occur in sardines. Therefore, planktivorous
fish may be a good tracer for the occurrence of offshore G. catenatum blooms and the associated PSTs produced by these algae. 相似文献
2.
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
3.
Noel H. Holmgren 《Brittonia》2018,70(1):115-139
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
4.
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
5.
D. J. Goyder 《Kew Bulletin》2008,63(2):331-333
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
6.
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
7.
Amanita concentrica sp. nov. is described from an evergreen broad-leaved forest of Chiba Prefecture with Castanopsis cuspidata var. sieboldii and Quercus glauca. The fungus is a medium to large, white to yellowish-white mushroom characterized by many pyramidal warts on pileus, striate
margin of pileus, distinct ascending concen-tric rings at upper part of stipe bulb, and inamyloid basidiospores. It is considered
to belong to the section Amanita.
Received: March 30, 2001 / Accepted: October 1, 2001 相似文献
8.
The cattle tick Rhipicephalus (Boophilus) microplus is known to be a highly reproductive and efficient vector of Babesia bovis, two characters which make this tick a threat to livestock keeping in many continents. The authors identified this tick in
Ivory Coast, West Africa, in 2007, and hypothesized the spread to be minimal, as this tick was not observed in previous years.
To determine the extent of its distribution and to a lesser extent the possible impact of the tick on the livelihoods of Ivorian
smallholders, a cross-sectional survey was carried out in the Abidjan and Agboville Departments of Ivory Coast, in April 2008.
The results of the study reveal that the newly introduced tick has almost completely displaced all indigenous Rhipicephalus (Boophilus) species in the study area and gave rise to unsuccessful tick control, inappropriate pesticide use, loss of milk production
and even increased mortality in dairy cattle. 相似文献
9.
Shaghayegh Nasr Steffen Bien Mohammad Reza Soudi Nayyereh Alimadadi Seyed Abolhassan Shahzadeh Fazeli Ulrike Damm 《Mycological Progress》2018,17(6):755-771
During a study on the biodiversity of yeasts and yeast-like ascomycetes from wild plants in Iran, four strains of yeast-like filamentous fungi were isolated from a healthy plant of Euphorbia polycaulis in the Qom Province, Iran (IR. of). All four strains formed small hyaline one-celled conidia from integrated conidiogenous cells directly on hyphae and sometimes on discrete phialides, as well as by microcyclic conidiation. Two strains additionally produced conidia in conidiomata that open by rupture. The internal transcribed spacer (ITS) sequences suggested the placement of these strains in the genera Collophorina (Leotiomycetes) and Coniochaeta (Sordariomycetes), respectively. Blast search results on NCBI GenBank and phylogenetic analyses of ITS, the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and the translation elongation factor 1α (EF-1α) sequences, and the nuclear large subunit ribosomal gene (LSU), partial actin (ACT), and β-tubulin (TUB) sequences, respectively, revealed the isolates to belong to three new species, that are described here as Collophorina euphorbiae, Coniochaeta iranica, and C. euphorbiae. All three species are characterised by morphological, physiological, and molecular data. 相似文献
10.
The maT clade of transposons is a group of transposable elements intermediate in sequence and predicted protein structure to mariner and Tc transposons, with a distribution thus far limited to a few invertebrate species. We present evidence, based on searches of publicly available databases, that the nematode Caenorhabditis briggsae has several maT-like transposons, which we have designated as CbmaT elements, dispersed throughout its genome. We also describe two additional transposon sequences that probably share their evolutionary history with the CbmaT transposons. One resembles a fold back variant of a CbmaT element, with long (380-bp) inverted terminal repeats (ITRs) that show a high degree (71%) of identity to CbmaT1. The other, which shares only the 26-bp ITR sequences with one of the CbmaT variants, is present in eight nearly identical copies, but does not have a transposase gene and may therefore be cross mobilised by a CbmaT transposase. Using PCR-based mobility assays, we show that CbmaT1 transposons are capable of excising from the C. briggsae genome. CbmaT1 excised approximately 500 times less frequently than Tcb1 in the reference strain AF16, but both CbmaT1 and Tcb1 excised at extremely high frequencies in the HK105 strain. The HK105 strain also exhibited a high frequency of spontaneous induction of unc-22 mutants, suggesting that it may be a mutator strain of C. briggsae. 相似文献
11.
Buriev ZT Saha S Shermatov SE Jenkins JN Abdukarimov A Stelly DM Abdurakhmonov IY 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,123(8):1359-1373
The Gossypium MIC-3 (Meloidogyne Induced Cotton-3) gene family is of great interest for molecular evolutionary studies because of its uniqueness to Gossypium species, multi-gene content, clustered localization, and root-knot nematode resistance-associated features. Molecular evolution
of the MIC-3 gene family was studied in 15 tetraploid and diploid Gossypium genotypes that collectively represent seven phylogenetically distinct genomes. Synonymous (dS) and non-synonymous (dN) nucleotide substitution rates suggest that the second of the two exons of the MIC-3 genes has been under strong positive selection pressure, while the first exon has been under strong purifying selection to
preserve function. Based on nucleotide substitution rates, we conclude that MIC-3 genes are evolving by a birth-and-death process and that a ‘gene amplification’ mechanism has helped to retain all duplicate
copies, which best fits with the “bait and switch” model of R-gene evolution. The data indicate MIC-3 gene duplication events occurred at various rates, once per 1 million years (MY) in the allotetraploids, once per ~2 MY in
the A/F genome clade, and once per ~8 MY in the D-genome clade. Variations in the MIC-3 gene family seem to reflect evolutionary selection for increased functional stability, while also expanding the capacity
to develop novel “switch” pockets for responding to diverse pests and pathogens. Such evolutionary roles are congruent with
the hypothesis that members of this unique resistance gene family provide fitness advantages in Gossypium. 相似文献
12.
Plants have evolved several defense mechanisms, including resistance genes. Resistance to the root-knot nematode Meloidogyne
incognita has been found in wild plant species. The molecular basis for this resistance has been best studied in the wild tomato Solanum peruvianum and it is based on a single dominant gene, Mi-1.2, which is found in a cluster of seven genes. This nematode attacks fiercely several crops, including potatoes. The genomic
arrangement, number of copies, function and evolution of Mi-1 homologs in potatoes remain unknown. In this study, we analyzed partial genome sequences of the cultivated potato species
S. tuberosum and S. phureja and identified 59 Mi-1 homologs. Mi-1 homologs in S. tuberosum seem to be arranged in clusters and located on chromosome 6 of the potato genome. Previous studies have suggested that Mi-1 genes in tomato evolved rapidly by frequent sequence exchanges among gene copies within the same cluster, losing orthologous
relationships. In contrast, Mi-1 homologs from cultivated potato species (S. tuberosum and S. phureja) seem to have evolved by a birth-and-death process, in which genes evolve mostly by mutations and interallelic recombinations
in addition to sequence exchanges. 相似文献
13.
14.
15.
Notocactus scopa cv. Soonjung was subjected to in planta Agrobacterium tumefaciens-mediated transformation with vacuum infiltration, pin-pricking, and a combination of the two methods. The pin-pricking combined with vacuum infiltration (20-30 cmHg for 15 min) resulted in a transformation efficiency of 67-100%, and the expression of the uidA and nptII genes was detected in transformed cactus. The established in planta transformation technique generated a transgenic cactus with higher transformation efficiency, shortened selection process, and stable gene expression via asexual reproduction. All of the results showed that the in planta transformation method utilized in the current study provided an efficient and time-saving procedure for the delivery of genes into the cactus genome, and that this technique can be applied to other asexually reproducing succulent plant species. 相似文献
16.
A new Dactylella species, Dactylella alba was isolated from the ascospores of Orbilia alba collected in Wenshan County, Yunnan Province, China. Conidiophores were either not branched or occasionally branched, bearing
divergent sterigmata on the tip with single conidium on each. Conidia were elongated ellipsoids, 1–2 septate, mostly 1 septate.
By combining the ITS sequence with morphological characteristics, a new anamorphic species is described and illustrated together
with its teleomorph. 相似文献
17.
Stefanie Kimbacher Ingrid Gerstl Branko Velimirov Sylvia Hagemann 《Molecular genetics and genomics : MGG》2009,282(2):165-172
P transposons belong to the eukaryotic DNA transposons, which are transposed by a cut and paste mechanism using a P-element-coded transposase. They have been detected in Drosophila, and reside as single copies and stable homologous sequences in many vertebrate species. We present the P elements Pcin1, Pcin2 and Pcin3 from Ciona intestinalis, a species of the most primitive chordates, and compare them with those from Ciona savignyi. They showed typical DNA transposon structures, namely terminal inverted repeats and target site duplications. The coding
region of Pcin1 consisted of 13 small exons that could be translated into a P-transposon-homologous protein. C. intestinalis and C. savignyi displayed nearly the same phenotype. However, their P elements were highly divergent and the assumed P transposase from C. intestinalis was more closely related to the transposase from Drosophila melanogaster than to the transposase of C. savignyi. The present study showed that P elements with typical features of transposable DNA elements may be found already at the base of the chordate lineage.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
18.
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
19.
20.
Sphaerellothecium stereocaulorum sp. nov., Stigmidium beringicum sp. nov., Stigmidium stereocaulorum sp. nov. and goniocysts are described on Stereocaulon species from the northern Holarctic. Endococcus nanellus is reported new to Alaska and Mongolia.
Taxonomical novelties
Sphaerellothecium stereocaulorum Zhurb. & Triebel, Stigmidium beringicum Zhurb. & Triebel, Stigmidium stereocaulorum Zhurb. & Triebel. 相似文献