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1.
Introduced herbivores are major drivers of ecosystem change and biodiversity loss, particularly on islands. Tools and techniques now exist to routinely remove introduced herbivores from islands, providing a powerful conservation tool. Here, we summarize the few documented feral donkey removals on islands worldwide, and report on the removal of populations from the Galápagos archipelago, Ecuador. After decades of sporadic control programs on Santiago Island and Alcedo Volcano, Isabela Island, donkey populations were removed from both areas, concurrent with a goat eradication program. Both ground and aerial hunting programs were utilized. The latter method was highly efficient; donkeys were removed from Santiago Island with less than 80 h of aerial hunting. Given the clear impacts of introduced herbivores on islands worldwide, feral donkey populations should be routinely removed from islands.  相似文献   

2.
The major histocompatibility complex (MHC) is one of the most polymorphic regions of the genome, likely due to balancing selection acting to maintain alleles over time. Lack of MHC variability has been attributed to factors such as genetic drift in small populations and relaxed selection pressure. The Galápagos penguin (Spheniscus mendiculus), endemic to the Galápagos Islands, is the only penguin that occurs on the equator. It relies upon cold, nutrient-rich upwellings and experiences severe population declines when ocean temperatures rise during El Niño events. These bottlenecks, occurring in an already small population, have likely resulted in reduced genetic diversity in this species. In this study, we used MHC class II exon 2 sequence data from a DRB1-like gene to characterize the amount of genetic variation at the MHC in 30 Galápagos penguins, as well as one Magellanic penguin (S. magellanicus) and two king penguins (Aptenodytes patagonicus), and compared it to that in five other penguin species for which published data exist. We found that the Galápagos penguin had the lowest MHC diversity (as measured by number of polymorphic sites and average divergence among alleles) of the eight penguin species studied. A phylogenetic analysis showed that Galápagos penguin MHC sequences are most closely related to Humboldt penguin (Spheniscus humboldti) sequences, its putative sister species based on other loci. An excess of non-synonymous mutations and a pattern of trans-specific evolution in the neighbor-joining tree suggest that selection is acting on the penguin MHC.  相似文献   

3.
The lipase Lip2 of the edible basidiomycete, Pleurotus sapidus, is an extracellular enzyme capable of hydrolysing xanthophyll esters with high efficiency. The gene encoding Lip2 was expressed in Escherichia coli TOP10 using the gene III signal sequence to accumulate proteins in the periplasmatic space. The heterologous expression under control of the araBAD promoter led to the high level production of recombinant protein, mainly as inclusion bodies, but partially in a soluble and active form. A fusion with a C-terminal His tag was used for purification and immunochemical detection of the target protein. This is the first example of a heterologous expression and periplasmatic accumulation of a catalytically active lipase from a basidiomycete fungus.  相似文献   

4.
We undertook a field study to determine whether comb cell size affects the reproductive behavior of Varroa destructor under natural conditions. We examined the effect of brood cell width on the reproductive behavior of V. destructor in honey bee colonies, under natural conditions. Drone and worker brood combs were sampled from 11 colonies of Apis mellifera. A Pearson correlation test and a Tukey test were used to determine whether mite reproduction rate varied with brood cell width. Generalized additive model analysis showed that infestation rate increased positively and linearly with the width of worker and drone cells. The reproduction rate for viable mother mites was 0.96 viable female descendants per original invading female. No significant correlation was observed between brood cell width and number of offspring of V. destructor. Infertile mother mites were more frequent in narrower brood cells.  相似文献   

5.
Non-native invasive species threaten Galápagos’ endemic biodiversity, and increasing efforts are underway to protect its species from further harm. One such project is focused on the eradication of invasive rodents using rodenticide bait on Floreana, the archipelago’s sixth largest island. Short-eared owls (Asio flammeus galapagoensis) that consume poisoned rodents will, therefore, be at risk of secondary poisoning. If negatively impacted, it is not known to what degree the Floreana Island short-earned owl population is isolated, and whether potential re-colonization exists from its closest neighboring large population on Santa Cruz. Based on eight microsatellite loci and mtDNA control region sequence data from museum and contemporary samples, the short-eared owl populations on Floreana and Santa Cruz are not isolated from each other. However, gene flow is asymmetric from Floreana to Santa Cruz and not in the opposite direction. Morphometric data, including tarsus and bill size, and behavioral observations corroborate the genetic results and suggest that the Floreana population may possess unique traits compared to neighboring populations. For example, Floreana short-eared owls are more crepuscular than neighboring islands, which are predominately nocturnal, and were also non-responsive to inter-island call back recordings. Therefore, these results have important management implications concerning short-eared owl persistence on Floreana following rodenticide application. We recommend that managers implement additional precautions to protect the short-eared owl population until the risk of secondary poisoning has passed such as maintaining individuals in captivity. This study provides no evidence to suggest that short-eared owls are likely to disperse from Floreana’s closest large population on Santa Cruz if the local population is negatively impacted by rodenticide exposure, and the observed morphological and behavioral traits argue against translocating owls between islands.  相似文献   

6.
Dana Bernátová 《Biologia》2008,63(2):175-176
The paper brings information on an isolated occurrence and morphological characters of Carex × involuta and C. juncella populations in the Vel’ká Fatra Mts. Their presence has been known neither from the territory of Slovakia nor from the whole Western Carpathians till now.  相似文献   

7.
Throughout history, remote archipelagos have repeatedly been designated natural laboratories to study evolutionary processes. The extensive, geographically structured, morphological variation within Galápagos’ Opuntia cacti has been presumed to be another example of how such processes shape diversity. However, recent genetic studies on speciation and potential effects of plasticity within this system failed to confirm earlier classification and hypothesized radiation on both global and single island levels. Detailed population genetic information, however, is crucial in conserving these semi-arid ecosystem keystone species. In this article, we re-evaluate the genetics of Opuntia echios inhabiting one of the most taxon rich places on the archipelago: Santa Cruz and its surrounding satellite islands, using microsatellite data. Our analysis revealed high genetic variability within all sampled locations, providing little support for the hypothesis of clonal reproduction. Inter-island gene flow patterns appear to be largely influenced by bathymetry and sea levels during last ice ages. Although O. echios from Seymour Norte are morphologically recognized as being a separate taxon, Daphné Major’s cacti are the most differentiated. In addition, we found a potential barrier for gene flow along the ring-like distribution of Opuntias at the western side of Santa Cruz, suggesting potential links with geology.  相似文献   

8.
Efficient transformation of leaf disc-derived callus of Codonopsis lanceolata was obtained using Agrobacterium tumefaciens strain LBA4404 harboring a binary vector, pYBI121, that carries the neomycin phosphotransferase (npt II) gene as a selectable marker. The green shoots recovered from agroinfected explants on selection medium (containing 0.1 mg/l α-naphthaleneacetic acid (NAA), 1 mg/l 6-benzylaminopurine (BAP), 100 mg/l kanamycin, and 250 mg/l cefotaxime) were rooted on Murashige and Skoog (MS) medium supplemented with 2 mg/l IBA and 10 mg/l kanamycin. To optimize the transformation conditions, several factors were assessed, including the co-cultivation period, the duration of pre- and post-culture in darkness and light, the kanamycin concentration, and the Agrobacterium densities. We produced transgenic Codonopsis lanceolata overexpressing γ-tocopherol methyltransferase (γ-TMT) by this protocol. Moreover, the α-tocopherol content of the plants was enhanced by the overexpression of this gene. Bimal Kumar Ghimire and Eun Soo Seong contributed equally to this work.  相似文献   

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11.
Previously, we have described the use of phage display to generate high affinity disulfide bond-linked T cell receptors (TCRs). The affinities of the mutant TCRs were analysed after refolding of separately expressed α and β chains from Escherichia coli inclusion bodies. This approach is only suitable for the analysis of small numbers of TCR variants. An attractive alternative would be soluble expression within the bacterial periplasm, but the generic production of TCRs within the E. coli periplasm has so far not proved successful. Here we show that functional, soluble TCR can be produced within the cytoplasm of trxB gor mutant E. coli strains, with maximum yields of 3.4 mg/l. We also investigated the effect of coexpressing the folding modulators Skp and DsbC finding that the TCR expression levels were largely unaffected by these chaperones. Importantly, we demonstrated that the amount of protein purified from 50 ml starter cultures was sufficient to show functionality of the TCR by specific antigen binding in both ELISA and surface plasmon resonance (SPR) assays. This TCR production method has the potential to allow rapid and medium throughput analysis of affinity-matured TCRs selected from TCR phage display libraries.  相似文献   

12.
13.
Verbena (Verbena x hybrida), an important floricultural species, was successfully regenerated from stem segments on Murashige and Skoog's basal medium supplemented with thidiazuron and indole-3-acetic acid. A transformation system was developed using cvs. Temari Scarlet, Temari Sakura, Tapien Rose and TP-P2. Agrobacterium tumefaciens strain Agl0 harboring the sGFP gene was infected into stem segments. Transformation efficiency was improved by evaluating and manipulating the age of the plant material, the concentration of kanamycin in the medium during selection, and the length of the culture period in the dark. After 2-3 months of culture on the selection medium, GFP-positive shoots were obtained in all four of the cultivars tested. These shoots were successfully acclimated and set flowers within 2-3 months in a greenhouse. GFP was expressed in all of the organs including the floral parts. Stable genomic transformation was confirmed by Southern blot analysis. No morphological differences were observed between the transformed plants and their host plants.  相似文献   

14.
15.
Much attention has been focused on the study of lactoferrin at the protein or nucleotide level in mice, humans, and cattle, but little is known about it in goats. The goat LF gene from 5' UTR to exon 17 was amplified, and the variation of g.7605C→T in 10 Chinese indigenous goat breeds was analyzed. Among the three ruminant species (cattle, sheep, and goats), the intron-exon distribution pattern was similar, and all the exons had the same length, but the length of introns varied greatly due to insertions or deletions. The frequency of allele T at g.7605C→T (50.12%) was a little higher than that of allele C (49.88%), and the genotype distribution differed greatly between goat populations. The g.7605C→T site showed higher genetic diversity in goat populations. The genetic differentiation was 0.0783, and gene flow was 2.9433 among the 10 Chinese indigenous goat populations.  相似文献   

16.
Functional expression of heterologous Pseudozyma antarctica lipase B (PalB) in the periplasm of Escherichia coli was explored using four fusion tags, i.e. DsbC, DsbA, maltose-binding protein (MBP), and FLAG in the sequence of increasing expression efficacy. Amongst these fusion tags, FLAG and MBP appear to be the most effective ones in terms of boosting enzyme activity and enhancing solubility of PalB, respectively. Overexpression of these PalB fusions often resulted in concomitant formation of insoluble inclusion bodies. Coexpression of a selection of periplasmic folding factors, including DegP (and its mutant variant of DegPS210A), FkpA, DsbA, DsbC, and a cocktail of SurA, FkpA, DsbA, and DsbC, could improve the expression performance. Coexpression of DsbA appeared to be the most effective in reducing the formation of inclusion bodies for all the four PalB fusions, implying that functional expression of PalB could be limited by initial bridging of disulfide bonds. Culture performance was optimized by overexpressing FLAG-PalB with DsbA coexpression, resulting in a high volumetric PalB activity of 360 U/L.  相似文献   

17.
Root segments from seedlings of Panax ginseng produced adventitious roots directly when cultured on 1/2 MS solid medium lacking NH4NO3 and containing 3.0 mg l−1 IBA. Using this adventitious root formation, we developed rapid and efficient transgenic root formation directly from adventitious root segments in P. ginseng. Root segments were co-cultivated with Agrobacterium tumefaciens (GV3101) caring β-glucuronidase (GUS) gene. Putative transgenic adventitious roots were formed directly from root segments on medium with 400 mg l−1 cefotaxime and 50 mg l−1 kanamycin. Kanamycin resistant adventitious roots were selected and proliferated as individual lines by subculturing on medium with 300 mg l−1 cefotaxime and 50 mg l−1 kanamycin at two weeks subculture interval. Frequency of transient and stable expression of GUS gene was enhanced by acetosyringon (50 mg l−1) treatment. Integration of transgene into the plants was confirmed by the X-gluc reaction, PCR and Southern analysis. Production of transgenic plants was achieved via somatic embryogenesis from the embryogenic callus derived from independent lines of adventitious roots. The protocol for rapid induction of transgenic adventitious roots directly from adventitious roots can be applied for a new Agrobacterium tumefaciens-mediated genetic transformation protocol in P. ginseng.  相似文献   

18.
In situ Management and Patterns of Morphological Variation of Ceiba aesculifolia subsp. parvifolia (Bombacaceae) in the Tehuacán-Cuicatlán Valley. Archaeological studies in Mexico’s Tehuacán Valley that were conducted during the 1960s revealed that the prehistoric use of “pochote” Ceiba aesculifolia was mainly for its edible roots and seeds. Recent ethnobotanical studies in the villages of Coxcatlán, San Rafael, and San José Tilapa, municipality of Coxcatlán, Puebla, documented that currently seeds are the most important plant parts of this tree used in the region. Local people recognize three morphological types of pochote trees: the purple-reddish, the pale green, and the dark-green reddish fruit variants, the first two being preferred because of their larger and more abundant seeds. This study documents the patterns of morphological variation of C. aesculifolia in human-managed and unmanaged populations in the communities just mentioned in order to analyze whether management has been directed to favor abundance of morphological types preferred by people. The main morphological types named by people were characterized by morphometric studies, and their frequencies in populations under different management intensity were evaluated through vegetation sampling. The morphometric studies corroborated that the morphological types recognized by people are identifiable groups, whereas vegetation sampling revealed that pochote variants preferred by people (the purple-reddish fruit type) were relatively more abundant in human-managed areas than in natural vegetation. This information suggests the occurrence of artificial selection associated with in situ management of this plant species.  相似文献   

19.
Using yeast genome databases and literature data, we have conducted a phylogenetic analysis of pectinase PGU genes from Saccharomyces strains assigned to the biological species S. arboricola, S. bayanus (var. uvarum), S. cariocanus, S. cerevisiae, S. kudriavzevii, S. mikatae, S. paradoxus, and hybrid taxon S. pastorianus (syn. S. carlsbergensis). Single PGU genes were observed in all Saccharomyces species, except S. bayanus. The superfamily of divergent PGU genes has been documented in S. bayanus var. uvarum for the first time. Chromosomal localization of new PGU1b, PGU2b, and PGU3b genes in the yeast S. bayanus var. uvarum has been determined by molecular karyotyping and Southern hybridization.  相似文献   

20.
Strigolactones (SLs) are a recently discovered type of plant hormone that controls various developmental processes. The DWARF53 (D53) protein in rice and the SMAX1-LIKE (SMXL) family in Arabidopsis repress SL signaling. In this study, bioinformatics analyses were performed, and 236 SMXL proteins were identified in 28 sequenced plants. A phylogenetic analysis indicated that all potential SMXL proteins could be divided into three groups and that the SMXL proteins may have originated in Bryophytes. An analysis of the SMXL chromosomal locations suggested that gene duplication events at different times led to expansion of the SMXL family members in Angiospermae. Subsequently, the gene structure and protein modeling of MdSMXLs showed that they are highly conserved. The expression patterns of MdSMXLs indicated that they were expressed in different organs of apple (stems, roots, leaves, flowers, and fruits) at varying levels and that MdSMXLs may participate in the SL signaling pathway and the response to abiotic stress. This study provides a valuable foundation for additional investigations into the function of the SMXL gene family in plants.  相似文献   

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