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1.
We describe for the first time the karyotypes of two species of Cryptodiran turtles from Argentina, namely, Trachemys dorbigni (Emydidae) and Chelonoidis (Geochelone) donosobarrosi (Testudinidae). The karyotype of T. dorbigni (2n = 50) consists of 13 pairs of macrochromosomes and 12 pairs of microchromosomes, whereas the karyotype of C. donosobarrosi (2n = 52) consists of 11 pairs of macrochromosomes and 15 pairs of microchromosomes. Fluorescence in situ hybridization (FISH) with a (TTAGGG)n telomeric probe showed that the chromosomes of these species have four telomeric signals, two at each end, indicating that none of the chromosomes of T. dorbigni and C. donosobarrosi are telocentric. The fact that no interstitial telomeric signals were observed after FISH, suggests that interstitial telomeric sequences did not have a major role in the chromosomal evolution of these species. Additional data will be needed to elucidate if interstitial telomeric sequences have a major role in the karyotypic evolution of Testudines.  相似文献   

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The results of a study of morphological character variability in the populations of R. altaicus s. l., R. sulphureus subsp. exaltatus and R. schmakovii are presented. Univariate and multivariate analysis methods have been applied: a principal components method, discriminant and variance analysis. As a result, two Altai buttercup subspecies have been distinguished in the territory of the Altai mountains (R. altaicus subsp. altaicus, R. altaicus subsp. frigidus), as well as the new taxa R. sulphureus subsp. exaltatus and R. schmakovii  相似文献   

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The accurate identification of taxa of Aotus is essential for 1) the development of precise biomedical assays, 2) the determination of potential illegal traffic of this genus, and 3) conservation. Although many studies have contributed to what we know about the phylogenetics of Aotus, none used a sufficiently large number of samples to clarify its complexity. To address this need, we sequenced 696 base pairs of the mitochondrial cytochrome-oxidase II gene (mtCOII) in 69 specimens of 7 taxa of Aotus. We also analyzed 8 microsatellite loci in 136 individuals of 6 taxa. In contrast to previous studies, we sampled only wild individuals and have a precise geographical origin for each one. The mtDNA results showed that: 1) the northern gray-necked group of Aotus is genetically more homogeneous than the polyphyletic red-necked group of Aotus; 2) the ancestors of Aotus vociferans seem to be the original species candidate for the current Aotus; 3) Aotus azarae azarae and A. a. boliviensis are the most differentiated taxa, likely a result of extreme genetic drift during stasipatric speciation; 4) the first genetic splits found among taxa of Aotus occurred during the Pliocene (or even Miocene) while the most recent ones happened during the Pleistocene, when forest refugia may have played an important role in speciation. The mean number of microsatellite alleles was 3–5.33 alleles per locus. We found some private alleles that could be useful in helping to identify illegal trade, although a larger sample size is needed to ensure that these alleles are really private to the relevant taxa. These new findings increase our understanding of the phylogeny of Aotus and the level of genetic diversity within different taxa of Aotus.  相似文献   

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Dabry's sturgeon (Acipenser dabryanus) represents an ancient Actinopterygian lineage that are termed “living fossils”. Many diseases have been found in Dabry's sturgeon. In the present study, genes encoding interleukin (IL)‐16 and IL‐17D in Dabry's sturgeon were identified by RNA‐sequencing. Phylogenetic tree analysis suggested that they clustered together with the corresponding pro‐IL‐16 proteins and IL‐17D proteins from other fish. Sequence analysis revealed that IL‐17D protein was more conserved than pro‐IL‐16. Dabry's sturgeon pro‐IL‐16 contains four putative PDZ domains and do not include signal peptides, while IL‐17D only possesses signal peptides (1–25 aa). The expression patterns of IL‐16 and IL‐17D genes were investigated in Dabry's sturgeon to reveal their functions in disease. The expression level of IL‐16 showed no significant changes in embryos; however, the high expression level of IL‐17D at 0–14 hpf (hours post fertilization) implied the existence of maternal expression in the oocyte and an association with embryonic development. Tissue distribution analysis revealed that IL‐16 and IL‐17D proteins have potential functions in immune and non‐immune tissue compartments. IL‐16 and IL‐17D had different fold changes in primary spleen leukocytes after polyinosinic:polycytidylic acid (poly I:C) and lipopolysaccharide (LPS) administration, which suggested that IL‐16 has a stronger antiviral capability compared with its antibacterial response, and IL‐17D has a stronger antibacterial capability compared with its antiviral response. IL‐16 showed an earlier response to virus compared with IL‐17D, and IL‐17D showed earlier and shorter response to bacteria compared with IL‐16. Our findings suggested the roles of IL‐16 and IL‐17D in Dabry's sturgeon, and provided the theoretical basis for the prevention and control of diseases of Dabry's sturgeon.  相似文献   

7.
Specimens of Askenasia volvox from southwestern Indiana have a variable body shape and a size range of 29 × 22 μ m to 42 × 27 μ m. The pectinelles, membranelles, and cirri each number 47–48, and respectively have a length of 8–10, 20, and 30 μ m. The pectinelles arise from ciliary rows consisting of ~10 kinetosomes, and every membranelle originates from 2 adjacent rows of ~14–17 kinetosomes. Different algae as well as Bodo and certain other protozoa are ingested. The macronucleus, micronucleus, the cytoplasm and its inclusions, trichites, the function of the contractile vacuole, and movements and behavior are described.  相似文献   

8.
The tomato borer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is considered to be one of the most devastating pests affecting tomato crops in South America, where crop losses range from 60 to 100%. After its detection in the Spanish tomato-growing area at the end of 2006, it spread quickly to other European and northern African countries. Currently, T. absoluta management in these countries is mainly based on chemical treatments. Nonetheless, special emphasis is being placed on implementing environmentally safe strategies. Commercial formulates based on Bacillus thuringiensis may be a good alternative, as they have been used to control other insect pests successfully. The laboratory, greenhouse, and open-field experiments presented in this work are evidence that B. thuringiensis is highly efficient in controlling T. absoluta. First instar larvae were the most susceptible, while susceptibility was lower in second and third instar larvae. Our results have shown that the impact of T. absoluta can be greatly reduced by spraying only B. thuringiensis-based formulates, with no need for chemical insecticides. Furthermore, the integration of this technology with other biological control methods focused on T. absoluta eggs, such as the use of mirid predators or parasitoids, could reduce the number of B. thuringiensis treatments and the use of chemicals, with the consequent reduction of residues on fruits.  相似文献   

9.
Dynamics of growth and oxygen consumption during ontogenesis of insects with direct (striped shield bug Graphosoma lineatum L.) and indirect (cabbage moth Mamestra brassicae L.) development have been compared. The correlation between a character of energy metabolism alteration and peculiarities of development of the insects has been shown. Cyclic decrease of oxygen consumption during molt and sharp dropping during metamorphosis have been observed in insects with indirect development. The decrease of oxygen consumption has been observed in insects with direct development only during molts. The coefficient a of allometric dependence of oxygen consumption on body weight of imago for cabbage moth was two times higher than that for striped shield bug.  相似文献   

10.
The Iberian Peninsula has been identified as an important glacial refugium during the Pliocene and Pleistocene epochs for the genus Lampetra, providing intermittent refuge and postglacial opportunities for colonization and expansion. We used mitochondrial DNA markers to investigate the processes that have shaped present-day genetic constitution of the genus Lampetra within the Iberian Peninsula. We surveyed 1,173 bp of the cytochrome b gene and 829 bp of the genes ATPase subunits 6 and 8 in 233 individuals of Lampetra fluviatilis (L.) and Lampetra planeri (Bloch) from 21 localities along their distribution range in the Iberian Peninsula. We identified four highly divergent allopatric evolutionary lineages that evolved by fragmentation during the Pliocene and Pleistocene likely driven by environmental factors, namely regional geomorphic events. The high level of genetic divergence between the four lineages suggests that sufficient time has apparently passed by to originate a complex of incipient or cryptic resident species and allows the definition of four evolutionary significant units (ESUs) for L. planeri and one ESU for L. fluviatilis. These findings have important consequences for the interpretation of refugia biological diversity and have major implications on the conservation of these threatened species.  相似文献   

11.
Abstract: Generally, lycophytes are not well represented in Anisian floras. Nonetheless, four different genera, each with one species, have been distinguished in the Anisian flora from Kühwiesenkopf (Monte Prà della Vacca), Italy. They were well preserved and yielded leaf cuticles in all four taxa and in situ spores in two of them. Lycopia dezanchei gen. et sp. nov. is the most common form; it is characterized by a dichotomising creeping prostrate rhizome (representing the primary shoot axis) from which arise aerial axes, apically bifurcated and covered with bundles of long leaves. This taxon cannot be attributed to any of the lycophyte orders, but most resembles Lycopodiales. Two representatives of the Isoetales have been found, of which Isoetites brandneri sp. nov. is abundant. This species is characterized by a short stem, which is unusual for this genus. In situ immature microspores and megaspores were found in some specimens. Lepacyclotes bechstaedtii sp. nov. has a quadrilobe corm with fertile scales inserted in whorls or slightly helicoidally. Short sterile leaves arise distally from the corm in some specimens. Selaginellales are very rare in the flora; Selaginellites leonardii sp. nov. is represented by a strobilus that yielded both micro‐ and megaspores. Some sterile fragments have been found associated, but never in organic connection.  相似文献   

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Lisianthus [Eustoma grandiflorum (Raf.) Shinn] is a popular cut flower crop throughout the world, and the demand for this plant for cut flowers and potted plants has been increasing worldwide. Recent advances in genetic engineering have enabled the transformation and regeneration of plants to become a powerful tool for improvement of lisianthus. We have established a highly efficient plant regeneration system and Agrobacterium-mediated genetic transformation of E. grandiflorum. The greatest shoot regeneration frequency and number of shoot buds per explant are observed on media supplemented with 6-Benzylaminopurine (BAP) and α-Naphthalene acetic acid (NAA). We report an efficient plant regeneration system using leaf explants via organogenesis with high efficiency of transgenic plants (15%) in culture of 11 weeks’ duration. Further ectopic expression of two MADS box genes, LMADS1-M from lily (Lilium longiflorum) and OMADS1 from orchid (Oncidium Gower Ramsey), was performed in E. grandiflorum. Conversion of second whorl petals into sepal-like structures and alteration of third whorl stamen formation were observed in the transgenic E. grandiflorum plants ectopically expressing 35S::LMADS1-M. 35S::OMADS1 transgenic E. grandiflorum plants flowered significantly earlier than non-transgenic plants. This is the first report on the ectopic expression of two MADS box genes in E. grandiflorum using a simple and highly efficient gene transfer protocol. Our results reveal the potential for floral modification in E. grandiflorum through genetic transformation.  相似文献   

15.
Auxin response factors (ARFs) are an important family involved in auxin-mediated response through specific binding to auxin response elements (AuxREs). A few members of the ARF family have been functionally characterized in Arabidopsis, rice (Oryza sativa), Poplar (Populous trichocarpa). However, little is known about ARF genes in maize (Zea mays). We performed a comprehensive bioinformatics analysis of the maize ARF gene family including analysis of the genome sequence, conserved domains, chromosomal locations, phylogenetic relationships, gene duplication, and expression profiles. 35 ZmARF genes were identified and categorized into four groups (Class I, II, III, and IV). In addition, a segmental ZmARF duplication event was shown to play an important role in maize ARF gene expansion. 7 ZmARF genes had no expression in specific tissues we obtained, but presented in mixed tissues according to the NCBI EST database, respectively. These studies have laid the theoretical foundation for further functional verification of these ZmARF genes.  相似文献   

16.
A new species of Gyrodactylus von Nordmann, 1832 and the first monogenean reported from Botswana is described from the cichlid Pseudocrenilabrus philander philander,bringing the number of gyrodactylids described from the African Continent to 18. Gyrodactylus thlapi n. sp. can be readily discriminated from the other described species almost exclusively by the shape of its hamuli, which have short roots and large, elongate ventral bar attachment points with the dorsal bar attachment point, demarcating the junction between the hamulus shaft and the root, positioned at the anterior terminus of the attachment plane. The marginal hooks of G. thlapi n. sp., which most closely resemble those of G. groschafti Ergens, 1973, are compared and discussed.  相似文献   

17.
Uredo behnickiana (syn. Hemileia americana and H. oncidii) is known on orchids of the genera Cattleya, Epidendrum, Laelia, Lophiaris and Oncidium. Previously, only the uredinial stages of these fungi have been described. The telial stage of the rust species was found for the first time on Oncidium marshallianum. Because of a unique combination of morphological characters the fungus could not be assigned to Hemileia or any other known rust genus. Desmosorus is proposed, therefore, as a new genus with Desmosorus oncidii as the single known species. Desmosorus is characterised by (1) suprastomatal sori on which the spores are formed at the ends of branched hyphae, by (2) subglobose to ovoid, echinulate urediniospores with a smooth patch around the hilum and by (3) thin-walled, oblong elliptical to cylindrical teliospores with a rounded apex.  相似文献   

18.
Morphological and anatomical characters of four ectomycorrhizae with affinities to the genera Humaria, Geopora, and Trichophaea of Pyronemataceae (Pezizomycetes, Ascomycota) on Chinese Pine (Pinus tabulaeformis) are described. The ectomycorrhizae are yellowish brown to brown, and have pseudoparenchymatous outer mantle layers and partially warty emanating hyphae with thick walls and without clamps. Intrahyphal hyphae are present, and no rhizomorphs are formed. The four ectomycorrhizae are distinguishable by differences in cell shape of outer mantle layers and the presence of cystidia. Ectomycorrhizae of a possible Humaria species (Pinirhiza humarioides) lack cystidia and have irregularly inflated cells on the outer mantle layer that are connected with thin septa. The two ectomycorrhizae showing probable affinities to Geopora species (“P. daqingensis” and “P. geoporoides”) possess row-like arranged cells in the outer mantle layer and cell heaps, and differ by the presence or absence of cystidia as well as by the structure of the inner mantle layers. Ectomycorrhizae likely having been formed by a Trichophaea species (“P. trichophaeoides”) have oval to polygonal cells and no cystidia. The possible taxa affiliations were assessed by molecular-phylogenetic analyses of the internal transcribed spacer (ITS) and partial large subunit (LSU) nrDNA. Morphological and anatomical characters are discussed against the background of the LSU phylogeny.  相似文献   

19.
Nectar thieves may increase or decrease pollinator-mediated pollen flow and thus may have positive or negative effects on plant reproductive success. In temperate rainforests of South America, the hummingbird Sephanoides sephaniodes acts as both a pollinator and non-destructive nectar thief on Lapageria rosea. Although pollinators that also act as nectar thieves have the potential to significantly modify plant reproductive success, no previous study has addressed this. To determine how the mixed behaviour of S. sephanoides affects pollen flow, we experimentally exposed some flowers to nectar theft and excluded nectar thieves from other flowers. We then assessed pollen dispersal into the floral neighbourhood. Thieved flowers exported less pollen, but the pollen exported was transferred farther into the neighbourhood. Our findings indicate a trade-off between distance and amount of pollen flow.  相似文献   

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