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1.
Variation of the fore and hind wing lengths and the diameters of wing eyespots in two subspecies of Coenonympha hero (L.) from the central part of the species range was analyzed. Clinal variation was revealed, manifested in a gradual increase of the wing size and eyespot diameters from west to east in the Urals. Both in C. h. hero in the Urals and in C. h. perseis in Siberia, the northern peripheral populations had a specific wing pattern with eyespots smaller than in more southern parts of the corresponding ranges. In most cases, such climatic factors as the mean annual air temperature, precipitation, duration of the frost-free period, and humidity were shown to affect significantly the variation of morphological traits of C. hero. Chrono-geographical analysis of variation showed that in some cases the differences between the samples collected in the same locality in different years were comparable to or greater than geographic variation within the subspecies range. Thus, the population as a whole is influenced by climatic factors and weather conditions in a particular part of the range during a particular season; C. hero may therefore be a suitable object for monitoring the impact of environmental changes on insects.  相似文献   

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The flight period of Erebia ligea (Linnaeus, 1758) in the Sysert District of Sverdlovsk Province lasts from early July until early August only in the odd-numbered years. The species is characterized by protandry, its males emerging 5–7 days before females. Erebia ligea manifests sexual and seasonal variation of the wing length and diameter of the eyespots in the Middle Urals. According to the literature and newly obtained data, the relative male/female wing length varies within the species range. The vectors of the seasonal variation of the body size are opposite in the males and females: in early summer the largest males and the smallest females occur, then mediumsized individuals appear, while the smallest males and the largest females fly at the end of the warm period. Although the males of Erebia ligea are larger than females, the latter have larger eyespots on the wings. Seasonal variation of the diameters of the forewing eyespots is largely similar in the two sexes: individuals with larger spots appear earlier in the season than those with small spots. The eyespots treated as phenes in this study develop on the wings only if the remaining spots of the wing pattern attain a threshold size. A threshold nature was shown for P4 spot in M 3-Cu 1 cell of the fore wing and G2 spot in cell M 1M 2 of the hind wing. Individuals with and without phene G2 have opposite vectors of seasonal variation of the sizes of the rest spots of the hind wing pattern. It is apparently the threshold character of variation of these elements of the wing pattern that defines the variation of the proportion of phenetic combinations of the eyespots in the individuals emerging in different periods of the season. Describing phenetic variation at the population level, one should remember that the percentage of the “morphs” or phenetic combinations may vary during a season, especially in the protandric species.  相似文献   

4.
Jain N  Fries BC 《Mycopathologia》2008,166(4):181-188
Microorganisms that live in fluctuating environments must constantly adapt their behavior to survive. The host constitutes an important microenvironment in opportunistic and primary fungal pathogens like Cryptococcus neoformans (C. neoformans) and Cryptococcus gattii (C. gattii). In clonal populations, adaptation may be achieved through the generation of diversity. For fungi phenotype switching constitutes a mechanism that allows them to change rapidly. Both C. neoformans and C. gattii undergo phenotypic switching, which allows them to be successful pathogens and cause persistent disease. Similar to other encapsulated microbes that exhibit phenotypic variation, phenotypic switching in Cryptococcus changes the polysaccharide capsule. Most importantly, in animal models phenotypic switching affects virulence and can change the outcome of infection. Virulence changes because C. neoformans and C. gattii switch variants elicit different inflammatory responses in the host. This altered host response can also affect the response to antifungal therapy and in some cases may even promote the selection of switch variants. This review highlights the similarity and differences between phenotypic switching in C. neoformans and C. gattii, the two dominant species that cause cryptococcosis in humans.  相似文献   

5.
Traditionally viewed as an Andean grain crop,Chenopodium quinoa Willd. includes domesticated populations that are not Andean, and Andean populations that are not domesticated. Comparative analysis of leaf morphology and allozyme frequencies have demonstrated that Andean populations, both domesticated(quinua) and free-living(ajara), represent an exceptionally homogeneous unit that is well differentiated from allied domesticates of coastal Chile(quingua) and freeliving populations of the Argentine lowlands(C. hircinum). This pattern of relationships indicates that Andean populations represent a monophyletic crop/weed system that has possibly developed through cyclic differentiation (natural vs. human selection) and introgressive hybridization. Relative levels of variation suggest that this complex originated in the southern Andes, possibly from wild types allied withC. hircinum, with subsequent dispersal north to Colombia and south to the Chilean coast. Coastal populations were apparently isolated from post-dispersal differentiation and homogenization that occurred in the Andes. Other data point toward a center of origin in the northern Andes with secondary centers of genetic diversity subsequently developing in the southern Andes and the plains of Argentina. Comparative linkage of South American taxa, all tetraploid, with North American tetraploids of the subsection will eventually clarify this problem. While the possibility of a direct phyletic connection betweenC. quinoa and the Mexican domesticate(C. berlandieri subsp. nuttalliae,) cannot be excluded, available evidence indicates that the latter represents an autonomous lineage that is associated with the basal tetraploid, C. b. subsp.berlandieri, through var.sinuatum, whereas South American taxa show possible affinities to either var. zschackei or var.berlandieri. An extinct domesticate of eastern North America,C. b. subsp.jonesianum, represents either another instance of independent domestication, possibly from subsp. b. var.zschackei, or a northeastern outlier of subsp.nuttalliae.  相似文献   

6.
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   

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   

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Agrobacterium tumefaciens-mediated transformation system was established for Hybanthus enneaspermus using leaf explants with the strain LBA4404 harbouring pCAMBIA 2301 carrying the nptII and gusA genes. Sensitivity of leaf explants to kanamycin was standardized (100 mg/l) for screening the transgenic plants. Transformation parameters (OD, virulence inducer, infection time, co-cultivation period, bactericidal antibiotics, etc.) influencing the gene transfer and integration were assessed in the present investigation. Fourteen-day pre-cultured explants were subjected with Agrobacterium strain LBA4404. Optimized parameters such as culture density of 0.5 OD600, infection time of 6 min, AS concentration of 150 µM with 3 days co-cultivation revealed maximum transformation efficiency based on GUS expression assay. The presence of gusA in transgenics was confirmed by polymerase chain reaction and Southern blotting analysis. The present transformation experiment yielded 20 shoots/explant with higher transformation efficiency (28 %). The protocol could be used to introduce genes for trait improvement as well as for altering metabolic pathway for secondary metabolites production.  相似文献   

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Single (unpaired) vegetative cells of freshwater pennate diatom Neidium cf. ampliatum differentiated into gametangia and produced a single zygote (auxospore) via a pedogamic process. The gametic nuclei fused after auxospore expansion had begun. The auxospore expanded in parallel to the apical axis of the gametangium.  相似文献   

12.
We have studied the molecular characteristics of the yellow locus (y; 1–0.0), which determines the body color of phenotypically wild-type and mutant alleles isolated in different years from geographically distant populations of Drosophila melanogaster. According to the Southern blot, data restriction maps of the yellow locus of all examined strains differ from one another, as well as from Oregon stock. FISH analysis shows that, in the neighborhood of the yellow locus in the X chromosome, neither P nor hobo elements are found in y1–775 stock, while only hobo is found in these region in y1–859 and y1–866 stocks, only the P element is found in y+sn849 stock, and both elements are found in y1–719 stock. Thus, all yellow mutants studied are of independent origin. Locus yellow located on the end of X chromosome (region 1A5–8 on the cytologic map) carries significantly more transposon than retrotransposon induced mutations compared to the white locus (region 3C2). It is possible that, at the ends of Drosophila melanogaster chromosomes, transposons are more active than retrotransposons.  相似文献   

13.
The dwarf pomegranate (Punica granatum L. var. nana) is a dwarf ornamental plant that has the potential to be the model plant of perennial fruit trees because it bears fruits within 1 year of seedling. We established an Agrobacterium-mediated transformation system for the dwarf pomegranate. Adventitious shoots regenerated from leaf segments were inoculated with A. tumefaciens strain EHA105 harboring the binary vector pBin19-sgfp, which contains neomycin phosphotransferase (npt II) and green fluorescent protein (gfp) gene as a selectable and visual marker, respectively. After co-cultivation, the inoculated adventitious shoots were cut into small pieces to induce regeneration, and then selected on MS medium supplemented with 0.5 μM α-naphthaleneacetic acid (NAA), 5 μM N6-benzyladenine (BA), 0.3% gellan gum, 50 mg/l kanamycin, and 10 mg/l meropenem. Putative transformed shoots were regenerated after 6–8 months of selection. PCR and PCR-Southern blot analysis revealed the integration of the transgene into the plant genome. Transformants bloomed and bore fruits within 3 months of being potted, and the inheritance of the transgene was confirmed in T1 generations. The advantage of the transformation of dwarf pomegranate was shown to be the high transformation rate. The establishment of this transformation system is invaluable for investigating fruit-tree-specific phenomena.  相似文献   

14.
We have investigated the floral ontogeny of Arillastrum, Allosyncarpia, Stockwellia and Eucalyptopsis (of the eucalypt group, Myrtaceae) using scanning electron microscopy and light microscopy. Several critical characters for establishing relationships between these genera and to the eucalypts have been determined. The absence of compound petaline primordia in Arillastrum, Allosyncarpia, Stockwellia and Eucalyptopsis excludes these taxa from the eucalypt clade. Post-anthesis circumscissile abscission of the hypanthium above the ovary in Stockwellia, Eucalyptopsis and Allosyncarpia is evidence that these three taxa form a monophyletic group; undifferentiated perianth parts and elongated fusiform buds are characters that unite Stockwellia and Eucalyptopsis as sister taxa. No floral characters clearly associate Arillastrum with either the eucalypt clade or the clade of Stockwellia, Eucalyptopsis and Allosyncarpia.We gratefully acknowledge Clyde Dunlop and Bob Harwood (Northern Territory Herbarium) for collecting specimens of Allosyncarpia, and Bruce Gray (Atherton) for collecting specimens of Stockwellia. The Australian National Herbarium (CANB) kindly lent herbarium specimens of Eucalyptopsis for examination. This research was supported by a University of Melbourne Research Development Grant to Andrew Drinnan.  相似文献   

15.
Euglossa viridissima is an orchid bee that forms both solitary and multiple female nests, making it a suitable species for the study of factors leading to diverse degrees of sociality in Euglossines. We conducted observations in eight reused nests (where a first generation of bees had been produced) kept in artificial boxes from the Yucatan Peninsula, Mexico. Five nests were reused (reactivated) by a single female (SFN), two nests reused by a mother and one daughter (MFN1) and one nest reused by the mother and two daughters (MFN2). No single nest was reactivated by unrelated females. The number of foraging trips, their duration and the duration of cell provisioning was not different between SFN and MFN. The overall production of cells per female was not different either between both types of nest. However, in MFN although all females did lay eggs, there was a reproductive skew in favor of the mother (95 and 45% of the brood produced in MFN1 and MFN2 respectively). She showed reproductive control of her daughters through oophagy and displaying threatening behavior when the daughters tried to open a cell where she had laid an egg. Brood losses to parasites (Anthrax sp. (Bom-byliidae) and Hoplostelis bivittata (Megachilidae)) were only found in SFN which possibly reflects and advantage of MFN in this respect. Our results coupled with other studies in Euglossa, reveal that a wide range of social behaviors occur in this genus, from solitary and communal to primitive reproductive division of labor. Multiple factors involving different levels of pressure imposed by food availability and parasites may favor such a diverse range of nesting behaviors. Interestingly, female associations in E. viridissima seem a result of kin selection that is enforced by coercion from mother females on their daughters. More studies are needed to shed light upon the social organization of Euglossa and other Euglossines and on their phylogenetic relationships in order to trace the origins of eusociality in Apidae. Received 12 February 2008; revised 25 June 2008; accepted 17 July 2008.  相似文献   

16.
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   

17.

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   

18.
The results of studying the polymorphism and genetic structure of populations of D. salina and D. incarnata growing in Zabaykalsky krai and Buryatia are represented according to the data of allozyme analysis of eight genetic loci (PGI, NADHD, SKDH, GDH, PGM, DIA, ADH, and IDH). The specificity of the allelic structure of loci SKDH, PGM, and IDH is established, for which D. salina and D. incarnata reliably differ from each other. It is shown that interspecies introgressive hybrid complexes with different genetic structures were formed in Transbaikalia. Places of mass growth of D. incarnata were observed to have single plants of D. salina, the interspecies hybrids of the first and subsequent generations. Places of mass growth of D. salina were observed to contain only the hybrids that are not hybrids of the first generation. They were heterozygous not for three loci with differentiating alleles of both parents, SKDH, PGM, and IDH, but for only one of them. The degree of genetic differentiation among five populations of D. salina was on average 7.5% and that of D. incarnata was 7.1%, which in accordance with Wright’s estimation relates to mean values. The average value of FST for all studied populations of the two related species of the genus Dactylorhiza was 0.478, indicating a very high degree of genetic differentiation between D. salina and D. incarnata growing in Transbaikalia. The greatest differences between the species are for the allelic structure of loci SKDH, PGM, and IDH (FST was equal to 0.705, 0.976, and 0.762, respectively). Analysis of molecular variance (AMOVA) showed that populations of D. salina and D. incarnata in the zone where their ranges in Zabaykalsky krai and Buryatya overlap have essential differences both for the variation of alleles frequencies of eight loci (71%, d.f. = 9) and for the variability of genotypes (61%, d.f. = 9). Despite the fact that D. salina and D. incarnata explicitly share a gene flow as a result of interspecies hybridization, the genetic differentiation of populations of these related species remains at a high level.  相似文献   

19.
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   

20.
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