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1.
The problems of delimitation of species of Prosopis originate from the few morphological discontinuities which exist among some of them; some, however, originated as a result of wide distribution of germplasm without proper knowledge of the species, in particular, much material catalogued as P. juliflora, but being of other species, was distributed for reforestation projects worldwide. This work tests the morphological results obtained for P. pallida and P. limensis of the Peruvian–Ecuadorian coast and for P. juliflora of the Caribbean Basin of Colombia and Venezuela utilizing a study of AFLPs and a study of the morphology of plantlets developed in a conventional garden study. The phenogram obtained for the AFLPs demonstrates each of the three species to be a well differentiated cluster and the molecular variance between them is significantly greater than the variance within each species. Study of the plantlets also indicates statistically significant differences for four morphological characters between P. juliflora and the other two species (P. pallida and P. limensis). These results, in addition to the morphological differentiation evident between adult plants of P. pallida and P. limensis and the clear separation of these two species from P. juliflora, corroborate the genetic identity of the three taxa analyzed.  相似文献   

2.
The three species of flying fishes—Indo-Pacific Cypselurus poecilopterus, Central Pacific C. simus, and Eastern Pacific C. callopterus form a particular species group within the subgenus Poecilocypselurus. These species rather weakly differ in the body height, number of predorsal scales and number of gill rakers. The sculls of these three species are very much alike; there are just very small differences in the proportions of some bones and the number of skull lateral line canals and pores. It could be imagined that C. poecilopterus has appeared in the Indo-Malayan Archipelago area and thence extended in all directions (up to the coasts of the Eastern Africa, Northern and Eastern Australia, New Guinea and adjacent islands, the western islands of Polynesia and the waters of Japan). C. callopterus inhabiting warm waters of the Eastern Pacific and C. simus whose area is situated in the central part of the Pacific Ocean are seemingly derived from this species.  相似文献   

3.
The method of polymerase chain reaction with random primers (RAPD PCR) was used to identify the progeny of the crosses between three sturgeon species, Amur sturgeon (Acipenser schrenckii Brandt, 1869), Siberian sturgeon (A. baerii Brandt, 1869), and sterlet (A. ruthenus Linnaeus, 1758). Using ten primers, genetic variation in 70 yearlings, produced in seven individual crosses: Acipenser schrenckii × A. schrenckii, A. baerii × A. baerii, A. ruthenus × A. ruthenus, A. schrenckii × A. baerii, A. baerii × A. schrenckii, A. schrenckii × A. ruthenus, and A. ruthenus × A. schrenckii was described and evaluated. It was demonstrated that the samples composed of hybrids from individual crosses were more variable than the samples of parental species. On the other hand, pooled samples of hybrids from two cross directions were genetically less variable than the pooled samples of their parents. The three main features of the hybrid RAPD profiles identified included: (1) preservation of marker DNA fragments of both parents in one genome; (2) presence of specific DNA fragments, absent from both parents; and (3) dependence of the frequency of some DNA fragments from the cross direction. Multidimensional scaling clearly distinguishes in the space of three coordinates the individuals of original species and the hybrid progeny with differentiation in the groups of direct and backcross hybrids. Analysis of relationships (UPGMA and NJ) pointed to substantial differentiation between the species, as well as between the species and hybrid progeny. Close genetic relationships between direct and backcross hybrids were demonstrated. Multilocus RAPD markers in association with statistical methods are considered to be the useful tool for discrimination of interspecific hybrids of sturgeon. Possible reasons for the differences in the hybrid RAPD profiles are discussed. Original Russian Text ? K.V. Rozhkovan, G.N. Chelomina, E.I. Rachek, 2008, published in Genetika, 2008, Vol. 44, No. 11, pp. 1453–1460.  相似文献   

4.
Chromosome mapping of three common markers, ie major and 5S rRNA genes (rDNA) and telomeric repeats, and conventional chromosome bandings were applied to two sibling species, Apodemus sylvaticus Linnaeus, 1758 and A. flavicollis Melchior, 1834, to further investigate intra- and interspecific karyological differentiation in the genus Apodemus. A slight variation of the rDNA-patterns was detected between the two Apodemus species. In both of them, the major NORs were located on autosome pairs 8, 11, 12 and 22, while the two other rDNA sites detected on chromosomes 7 and 21 were variable in, respectively, A. sylvaticus and A. flavicollis. Several tiny rDNA sites were present on the sex chromosomes in both species, but their incidence was lower in A. flavicollis. Single 5S rDNA chromosomal sites were conserved on chromosome pair 20. No interstitial sites of telomeric repeats were present in either species. In the Sicilian population of A. sylvaticus, the constitutive heterochromatin pattern corresponded to the “sylvaticus-E1” cytotype, while A. flavicollis had a species-specific pattern restricted to centromeres of all chromosomes. The results are discussed in relation to cytogenetic data available for the genus, with emphasis on the Sylvaemus group/subgenus.  相似文献   

5.
The effects of β-lactam antibiotics (penicillin, carbenicillin and cefotaxime), cytokinins, and auxins including phenylacetic acid, a β-lactam breakdown product, were evaluated during in vitro shoot morphogenesis in two hybrid aspens; P. tremuloides × P. tremula (XTTa) and P. x canescens × P. grandidentata (XCaG). Although different callus and shoot induction media were used for both hybrids, the β-lactams often engendered similar responses. At concentrations of 1,000 mg l−1, carbenicillin adversely impacted shoot elongation and, to a lesser degree, shoot regeneration. Cefotaxime enhanced caulogenesis for all of the concentrations evaluated (125–500 mg l−1) especially when the cytokinin thidiazuron was used for shoot induction. The shoots formed faster and in greater numbers; and the improvements were significant (α = 0.05) for both hybrids. However, hyperhydricity was more problematic when cefotaxime was included in the media. The incidence of shoot hyperhydricity for the XCaG hybrid was more than twice as great for the highest cefotaxime concentration evaluated (500 mg l−1) than for the control (>90% vs. ~40%). Penicillin had an opposite effect. Hyperhydricity frequencies for the XCaG hybrid were lower when the media were supplemented with penicllin and the reductions were statistically significant at concentrations of 500–1,000 mg l−1. The effects of the antibiotics were generally not reproduced by the auxins (0.1–100 μM), including phenylacetic acid, or the other potential β-lactam degradation products evaluated (e.g. phenylmalonic acid, aminopenicillanic acid). The antibiotics may have affected shoot hyperhydicity indirectly via changes in the time course of shoot regeneration.  相似文献   

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7.
The status of two poorly known fiddler crabs, Uca iranica Pretzmann, 1971, from the Persian Gulf, and U. albimana (Kossmann, 1877), from the Red Sea, was studied using two mitochondrial genes: the large subunit (16S) ribosomal (r)RNA and cytochrome oxidase subunit I (COI). A molecular phylogeny shows both U. iranica and U. albimana to be members of a monophyletic U. lactea species-complex containing six taxa, with three highly supported internal clades. Uca iranica and U. albimana are the closest genetically, but are different enough to be considered valid species (16S rRNA nucleotide divergence > 7.0%, and COI > 11.9%), and form a highly supported “western” clade with U. annulipes (in line with the original morphological concept). A West Pacific “eastern” clade includes U. lactea in the north and the more widely ranging U. perplexa. An Australian endemic species, U. mjoebergi, forms a third monotypic clade.  相似文献   

8.
This study reviews the nominal taxa within the species “Nemachilus” stoliczkae and “N.” dorsonotatus, described by Herzenstein (1888). N. dorsonotatus, N. d. retropinnis, and N. plagiognathus are reviewed within the species Triplophysa stoliczkae; it is suggested that this species is represented by at least 5 subspecies. N. stoliczkae brevicauda, N. s. leptosoma (synonym, N. s. productus), and N. s. crassicauda are considered as valid species, the last 2 are related to the group including the species T. tenuis, T. choprai, T. tenuicauda, and T. yasinensis rather than with T. stoliczkae. It was shown that the “stoliczkae” species group (sensu Prokofiev, 2001) should be divided into three species groups: “stoliczkae” (s. str.), “tenuis,” and “robusta”; their diagnoses and the species composition are presented. A new species from the “stoliczkae” group is described (T. scapanognatha sp. nova), related to T. tanggulaensis (Zhu, 1982). Original Russian Text ? A.M. Prokofiev, 2007, published in Voprosy Ikhtiologii, 2007, Vol. 47, No. 1, pp. 5–25.  相似文献   

9.
Three new species of Lamellodiscus are described from four (including two undescribed) species of Gymnocranius off New Caledonia, South Pacific. All three species have a similar body anatomy and morphology of the haptoral hard parts and are distinguished on the basis of the male copulatory organ (MCO). Lamellodiscus tubulicornis n. sp. (type-host: G. grandoculis; other host: Gymnocranius sp. B) has an MCO with a tube and horn; L. magnicornis n. sp. (type-host: G. grandoculis; other hosts: G. euanus, Gymnocranius sp. A and Gymnocranius sp. B) has an MCO with a long horn and a membrane; L. parvicornis n. sp. (type-host: G. euanus; other hosts: G. grandoculis and Gymnocranius sp. B) has an MCO with a small horn and a membrane. Lamellodiscus epsilon Yamaguti, 1968 is redescribed based on the type-specimens (from Monotaxis grandoculis off Hawaii). Lamellodiscus sp. is recorded from Gnathodentex aureolineatus off New Caledonia. All these five species have lamellodiscs that exhibit a unique characteristic: the second lamella forms an almost closed circle, in contrast to all other described species of Lamellodiscus in which the second lamella has the form of one or two crescents. Lamellodiscus spp. are usually classified in two groups, the ‘ignoratus’ and ‘elegans’ groups, according to the structure of the lamellodisc; we propose a new ‘tubulicornis’ group for these five species. In addition to their lamellodisc structure, species of the tubulicornis group are also characterised by their egg (elongate in contrast to tetrahedral in the two other groups) and their hosts (monotaxine lethrinids as opposed to mainly sparids). The generic diagnosis of Lamellodiscus given by Amine & Euzet (2005) is amended to include species with elongate eggs.  相似文献   

10.
Aetheolabes goeldiensis n. g., n. sp. (Diplectanidae) is described from the gills of ‘pescada’ Plagioscion sp. (Sciaenidae) collected from the Baía de Marajó, about 30 km north of Belém, Pará, Brazil. The monotypic Aetheolabes n. g. is characterised, in part, by its type-species having the haptor and haptoral sclerites modified as a clasp for attachment to the gill tissue of its host, the copulatory complex situated far posterior to the intestinal bifurcation near the mid-length of the trunk, the vaginal pore apparently within the genital atrium, the tegument lacking scales, anchors atypical for diplectanids, and by lacking peduncular spines and squamodiscs. A. goeldiensis n. sp. closely resembles Diplectanum umbrinum Tripathi, 1957 from India and China by the haptoral sclerites forming a clasp, but differs from it primarily by the orientation of the reproductive organs and absence of squamodiscs.  相似文献   

11.
The in vitro effect of four isolates of the nematophagous fungi Duddingtonia flagrans (AC 001), Monacrosporium sinense (SF 53) and Pochonia chlamydosporia (VC 1 and VC 4) on eggs of Schistosoma mansoni was examined. One thousand S. mansoni eggs were plated on 2% water–agar with the grown isolates and control without fungus. After 7, 14 and 21 days, the eggs were removed and classified according to the following parameters: type 1, lytic effect without morphological damage to eggshell; type 2, lytic effect with morphological alteration of embryo and eggshell; and type 3, lytic effect with morphological alteration of embryo and eggshell, besides hyphal penetration and internal egg colonization. Significant differences (P < 0.01) were found among the studied fungal isolates for ovicidal activity, confirming type 3 effect for the isolates VC 1 and VC 4, which characterizes the ovicidal activity of a fungus. Type 3 effect was only found for P. chlamydosporia (VC 1 and VC 4) with 26.6 and 17.2%, 25.6 and 22.6%, 27.4 and 23.9% in the 7, 14 and 21 days respectively (P < 0.01). P. chlamydosporia can thus be a potential biological control agent for S. mansoni eggs.  相似文献   

12.
The symbionts of the macronuclei of Paramecium bursaria and P. caudatum, “Holospora curviuscula” 02AZ16 and H. obtusa 88Ti, respectively, were obtained and investigated. The 16S rDNA nucleotide sequences of “Holospora curviuscula” were obtained for the first time. The differences in 16S rDNA (3.4%) suggest their classification within the genus Holospora. Molecular phylogenetic analysis of the symbionts revealed that these intranuclear symbionts of the ciliates belonged to the order Rickettsiales, forming within a compact cluster of related species.  相似文献   

13.
The fungiid Heliofungia actiniformis is one of the most popular coral species in the Indonesian aquarium trade, yet information on the biology of this species is limited. H. actiniformis growth rates, population size–frequency distributions and the seasonality of recruitment rates were measured at three replicate sites in the Spermonde Archipelago, South Sulawesi. Growth and population models were applied to estimate coral ages, mortality rates and the size of maximum yield. Growth decreased linearly with polyp size. High numbers of attached polyps budded from clusters of stalks attached to the reef, with each cluster originating from the settlement of a sexually produced larva. Neither the settlement of sexual recruits, nor their asexual budding, showed seasonality. The overall population structure reflected the high mortality rates of young, attached polyps (Z = 0.5–0.6 yr−1), and the much lower mortalities of free-living individuals (Z = 0.05–0.08 yr−1). There were no statistically significant differences in overall mortality rates and the age–frequency distributions of polyps aged 0–15 years between the sites. Differences in the abundance of large H. actiniformis polyps at the three replicate sites were correlated with percent cover of coral rubble. The application of the Beverton and Holt model revealed the highest biomass per H. actiniformis recruit was 12 cm, corresponding to a polyp age of 20 years.  相似文献   

14.
The banding structures of chromosomes of three Palearctic species of chironomids of the genus Sergentia Kieffer, 1922 from the Irkutsk reservoir were comparatively analyzed: S. baueri Wülker et al., 1999 (2n = 8), S. prima Proviz et al., 1997 (2n = 8), and S. electa Proviz et al., 1999 (2n = 6). The S. baueri karyotype was taken as a standard in chromosome mapping. It was established that in contrast to S. baueri and S. prima the S. electa karyotype was formed due to a complex translocation: transfer of chromosome IV in the median part of chromosome III. The sequences of chromosome I bands were found to be completely homologous in all Palearctic species and in S. rara Proviz et al., 1999 (2n = 8) taken as the original species in the group of Baikalian endemics. In both groups, seven homozygous inversions were detected, of which the common one is the inversion in chromosome III. It was assumed on the basis of the results of the karyological analysis that among the Palearctic species S. baueri is most similar to the Baikalian endemics and S. electa is phylogenetically closer to S. prima. Specific features of the chromosome and morphological evolutions of the Sergentia genus species are considered.  相似文献   

15.
Summary We have molecularly cloned the rDt transposon, one component of the classic Dotted two-element system of controlling elements. The rDt transposon was identified as a DNA insertion in each of two independent mutation events of the maize A1 gene, a gene necessary for the biosynthesis of anthocyanin pigment. Both mutant alleles result in a stable, anthocyaninless phenotype in all plant tissues. When the transposon Dotted, (Dt), is present in the genome each allele exhibits a characteristic mutable phenotype (spots of anthocyanin pigmentation). The DNA insertion has been designated rDt, for it responds to or is regulated by the Dt element to allow expression of the otherwise mutated gene, and it had not been named in earlier genetic studies. Sequence analysis revealed the rDt element to be an identical 704 bp insertion within the two mutable alleles, but in opposite orientation and in different exons of the gene. rDt contains an imperfect terminal inverted repeat with similarity to transposable elements of various species. A duplication of 8 bp of the target host site is formed upon integration of the element, and the element is excised from the locus in a germinal revertant. The difference in phenotype of the two unstable alleles, a1 and am-1:Cache, is discussed.  相似文献   

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18.
The role of dinB gene in the appearing of antibiotics resistance was studied. Plasmid containing multi-copy dinB gene was transfected into E. coli to create an overexpression. The strains carrying multi-copies of dinB gene demonstrate a significant survival advantage over the wild strain. In vitro experiment, the dinB-overexpressed strain evolved resistance within 8 hours, while wild strain could not.In vivo experiment with mice model infected with dinB-overexpressed strain, resistant clones emerged significantly earlier and demonstrated significant higher level of resistance than those infected with the wild control strain. The results showed that dinB gene made a contribution in the appearing of the antibiotics resistance and has a potential as a target for prevention from the appearing of antibiotic resistance.  相似文献   

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20.
For hunting purposes, several millions of red-legged partridges (Alectoris rufa) are released each year in Spain, and these releases have the potential to introduce new parasites and disease into wild populations. We studied the prevalence of Escherichia coli, Campylobacter sp. and Salmonella sp. in the intestinal flora of red-legged partridges from three different husbandry groups: farm-reared, restocked and natural populations. Prevalence of E. coli was significantly higher in farm-reared (45%, p = 0.01) and restocked partridges (60%, p < 0.001) than in wild ones (6%, p > 0.05). The prevalence of Campylobacter sp. (23%, 100 out of 444) did not differ significantly between these three husbandry groups, and Salmonella sp. was only detected in a group of partridge chicks on one of the farms studied (0.9%, 5 out of 544). These results suggest that farm-reared and restocked partridges can act as carriers of these three enteropathogens and highlight a potential risk of transmission to natural populations via the releases of farm-reared partridges. However, future investigations are needed regarding the relation of the isolated bacteria with zoonotic strains and dissemination of antibiotic resistant microorganisms, especially E. coli, and to better evaluate the effect that these three enteropathogens have on partridge health and on the success of restocking with farm-reared birds.  相似文献   

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