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71.
72.
Tania González Felipe Eng Reinaldo Fraga Jennifer Fonseca Isis Amores 《Journal of applied genetics》2013,54(4):495-499
The glyceraldehyde-3-phosphate dehydrogenase promoter of the food yeast Candida utilis strain NRRL Y-660 was cloned to create a novel integrative vector for Agrobacterium tumefaciens-mediated transformation. The new binary vector harbors β-glucuronidase activity as reporter and kanamicin/geneticin resistance as selection marker. Recombinant clones of A. tumefaciens show kanamycin resistance and high β-glucuronidase activity under the control of the C. utilis promoter. This finding can be explained by the presence of a prokaryotic core in the yeast promoter, predicted by in silico analysis of the sequence. This is the first report about functionality of a yeast promoter in A. tumefaciens. 相似文献
73.
Recreational boats in tow between lakes are a known vector of the spread of aquatic invading species (AIS), but we have no test of the hypothesis that recreational boats are also a vector of secondary spread of AIS among freshwater ecosystems via in-water transport i.e., while boating between interconnected waterways. In this study, we surveyed recreational boaters travelling into Lake Simcoe (44°25′N, 79°20′W), Ontario, Canada, on their recreational activities, boat maintenance, and travel destinations, measured the degree of vessel fouling, and sampled all standing water and attached macrophytes associated with their vessels. A total of 321 zooplankton individuals comprising 15 different species were collected from the standing water in vessels, including veligers of the invasive zebra mussel Dreissena. The volume of water collected within the vessels significantly increased the number of zooplankton transported. Zooplankton species from pelagic habitats or with planktonic life stages were collected more frequently than species that occupy littoral or benthic habitats, likely reflecting the recreational activities of boaters. Patterns of boater activities, movements and hygiene habits, suggest recreational boating in the Lake Simcoe region is contributing to the spread of native and invasive species into nearby waterways. Our study validates the widespread assumption that recreational boats are an important in-water vector for the secondary spread of both native and invasive zooplankton species. Future management strategies to reduce the spread of AIS should be aimed at increasing awareness of boater hygiene practices, particularly the frequent draining of standing water. 相似文献
74.
Rossella Falcone Sara Bevacqua Erika Cerasti Emiliano Brunamonti Milena Cervelloni Aldo Genovesio 《PloS one》2013,8(12)
To solve novel problems, it is advantageous to abstract relevant information from past experience to transfer on related problems. To study whether macaque monkeys were able to transfer an abstract rule across cognitive domains, we trained two monkeys on a nonmatch-to-goal (NMTG) task. In the object version of the task (O-NMTG), the monkeys were required to choose between two object-like stimuli, which differed either only in shape or in shape and color. For each choice, they were required to switch from their previously chosen object-goal to a different one. After they reached a performance level of over 90% correct on the O-NMTG task, the monkeys were tested for rule transfer on a spatial version of the task (S-NMTG). To receive a reward, the monkeys had to switch from their previously chosen location to a different one. In both the O-NMTG and S-NMTG tasks, there were four potential choices, presented in pairs from trial-to-trial. We found that both monkeys transferred successfully the NMTG rule within the first testing session, showing effective transfer of the learned rule between two cognitive domains. 相似文献
75.
Giulia Falivelli Erika Mathes Lisabeth Elena Rubio de la Torre Gizeh Perez-Tenorio Giovanna Tosato Ombretta Salvucci Elena B. Pasquale 《PloS one》2013,8(11)
The Eph receptor tyrosine kinases mediate juxtacrine signals by interacting “in trans” with ligands anchored to the surface of neighboring cells via a GPI-anchor (ephrin-As) or a transmembrane segment (ephrin-Bs), which leads to receptor clustering and increased kinase activity. Additionally, soluble forms of the ephrin-A ligands released from the cell surface by matrix metalloproteases can also activate EphA receptor signaling. Besides these trans interactions, recent studies have revealed that Eph receptors and ephrins coexpressed in neurons can also engage in lateral “cis” associations that attenuate receptor activation by ephrins in trans with critical functional consequences. Despite the importance of the Eph/ephrin system in tumorigenesis, Eph receptor-ephrin cis interactions have not been previously investigated in cancer cells. Here we show that in cancer cells, coexpressed ephrin-A3 can inhibit the ability of EphA2 and EphA3 to bind ephrins in trans and become activated, while ephrin-B2 can inhibit not only EphB4 but also EphA3. The cis inhibition of EphA3 by ephrin-B2 implies that in some cases ephrins that cannot activate a particular Eph receptor in trans can nevertheless inhibit its signaling ability through cis association. We also found that an EphA3 mutation identified in lung cancer enhances cis interaction with ephrin-A3. These results suggest a novel mechanism that may contribute to cancer pathogenesis by attenuating the tumor suppressing effects of Eph receptor signaling pathways activated by ephrins in trans. 相似文献
76.
Erika L. Spaeth Christopher M. Booth Frank C. Marini 《Journal of visualized experiments : JoVE》2013,(79)
With the desire to understand the contributions of multiple cellular elements to the development of a complex tissue; such as the numerous cell types that participate in regenerating tissue, tumor formation, or vasculogenesis, we devised a multi-colored cellular transplant model of tumor development in which cell populations originate from different fluorescently colored reporter gene mice and are transplanted, engrafted or injected in and around a developing tumor. These colored cells are then recruited and incorporated into the tumor stroma. In order to quantitatively assess bone marrow derived tumor stromal cells, we transplanted GFP expressing transgenic whole bone marrow into lethally irradiated RFP expressing mice as approved by IACUC. 0ovarian tumors that were orthotopically injected into the transplanted mice were excised 6-8 weeks post engraftment and analyzed for bone marrow marker of origin (GFP) as well as antibody markers to detect tumor associated stroma using multispectral imaging techniques. We then adapted a methodology we call MIMicc- Multispectral Interrogation of Multiplexed cellular compositions, using multispectral unmixing of fluoroprobes to quantitatively assess which labeled cell came from which starting populations (based on original reporter gene labels), and as our ability to unmix 4, 5, 6 or more spectra per slide increases, we''ve added additional immunohistochemistry associated with cell lineages or differentiation to increase precision. Utilizing software to detect co-localized multiplexed-fluorescent signals, tumor stromal populations can be traced, enumerated and characterized based on marker staining.1 相似文献
77.
Gianguglielmo Zehender Erika Ebranati Renata Shkjezi Anna Papa Camilla Luzzago Elena Gabanelli Alessandra Lo Presti Alessia Lai Giovanni Rezza Massimo Galli Silvia Bino Massimo Ciccozzi 《PloS one》2013,8(11)
Crimean-Congo hemorrhagic fever (CCHF) is a zoonosis mainly transmitted by ticks that causes severe hemorrhagic fever and has a mortality rate of 5-60%. The first outbreak of CCHF occurred in the Crimean peninsula in 1944-45 and it has recently emerged in the Balkans and eastern Mediterranean. In order to reconstruct the origin and pathway of the worldwide dispersion of the virus at global and regional (eastern European) level, we investigated the phylogeography of the infection by analysing 121 publicly available CCHFV S gene sequences including two recently characterised Albanian isolates. The spatial and temporal phylogeny was reconstructed using a Bayesian Markov chain Monte Carlo approach, which estimated a mean evolutionary rate of 2.96 x 10-4 (95%HPD=1.6 and 4.7 x 10-4) substitutions/site/year for the analysed fragment. All of the isolates segregated into seven highly significant clades that correspond to the known geographical clades: in particular the two new isolates from northern Albania clustered significantly within the Europe 1 clade. Our phylogeographical reconstruction suggests that the global CCHFV clades originated about one thousand years ago from a common ancestor probably located in Africa. The virus then spread to Asia in the XV century and entered Europe on at least two occasions: the first in the early 1800s, when a still circulating but less or non-pathogenic virus emerged in Greece and Turkey, and the second in the early 1900s, when a pathogenic CCHFV strain began to spread in eastern Europe. The most probable location for the origin of this European clade 1 was Russia, but Turkey played a central role in spreading the virus throughout Europe. Given the close proximity of the infected areas, our data suggest that the movement of wild and domestic ungulates from endemic areas was probably the main cause of the dissemination of the virus in eastern Europe. 相似文献
78.
Background
As global environmental change accelerates, biodiversity losses can disrupt interspecific interactions. Extinctions of mutualist partners can create “widow” species, which may face reduced ecological fitness. Hypothetically, such mutualism disruptions could have cascading effects on biodiversity by causing additional species coextinctions. However, the scope of this problem – the magnitude of biodiversity that may lose mutualist partners and the consequences of these losses – remains unknown.Methodology/Principal Findings
We conducted a systematic review and synthesis of data from a broad range of sources to estimate the threat posed by vertebrate extinctions to the global biodiversity of vertebrate-dispersed and -pollinated plants. Though enormous research gaps persist, our analysis identified Africa, Asia, the Caribbean, and global oceanic islands as geographic regions at particular risk of disruption of these mutualisms; within these regions, percentages of plant species likely affected range from 2.1–4.5%. Widowed plants are likely to experience reproductive declines of 40–58%, potentially threatening their persistence in the context of other global change stresses.Conclusions
Our systematic approach demonstrates that thousands of species may be impacted by disruption in one class of mutualisms, but extinctions will likely disrupt other mutualisms, as well. Although uncertainty is high, there is evidence that mutualism disruption directly threatens significant biodiversity in some geographic regions. Conservation measures with explicit focus on mutualistic functions could be necessary to bolster populations of widowed species and maintain ecosystem functions. 相似文献79.
Courtship Sounds Advertise Species Identity and Male Quality in Sympatric Pomatoschistus spp. Gobies
Silvia S. Pedroso Iain Barber Ola Svensson Paulo J. Fonseca Maria Clara P. Amorim 《PloS one》2013,8(6)
Acoustic signals can encode crucial information about species identity and individual quality. We recorded and compared male courtship drum sounds of the sand goby Pomatoschistus minutus and the painted goby P. pictus and examined if they can function in species recognition within sympatric populations. We also examined which acoustic features are related to male quality and the factors that affect female courtship in the sand goby, to determine whether vocalisations potentially play a role in mate assessment. Drums produced by the painted goby showed significantly higher dominant frequencies, higher sound pulse repetition rates and longer intervals between sounds than those of the sand goby. In the sand goby, male quality was predicted by visual and acoustic courtship signals. Regression analyses showed that sound amplitude was a good predictor of male length, whereas the duration of nest behaviour and active calling rate (i.e. excluding silent periods) were good predictors of male condition factor and fat reserves respectively. In addition, the level of female courtship was predicted by male nest behaviour. The results suggest that the frequency and temporal patterns of sounds can encode species identity, whereas sound amplitude and calling activity reflects male size and fat reserves. Visual courtship duration (nest-related behaviour) also seems relevant to mate choice, since it reflects male condition and is related to female courtship. Our work suggests that acoustic communication can contribute to mate choice in the sand goby group, and invites further study. 相似文献
80.