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151.
Katerina Sam Eliska Kovarova Inga Freiberga Henriette Uthe Alexander Weinhold Leonardo R. Jorge Rachakonda Sreekar 《Ecology and evolution》2021,11(16):10917
- When searching for food, great tits (Parus major) can use herbivore‐induced plant volatiles (HIPVs) as an indicator of arthropod presence. Their ability to detect HIPVs was shown to be learned, and not innate, yet the flexibility and generalization of learning remain unclear.
- We studied if, and if so how, naïve and trained great tits (Parus major) discriminate between herbivore‐induced and noninduced saplings of Scotch elm (Ulmus glabra) and cattley guava (Psidium cattleyanum). We chemically analyzed the used plants and showed that their HIPVs differed significantly and overlapped only in a few compounds.
- Birds trained to discriminate between herbivore‐induced and noninduced saplings preferred the herbivore‐induced saplings of the plant species they were trained to. Naïve birds did not show any preferences. Our results indicate that the attraction of great tits to herbivore‐induced plants is not innate, rather it is a skill that can be acquired through learning, one tree species at a time.
- We demonstrate that the ability to learn to associate HIPVs with food reward is flexible, expressed to both tested plant species, even if the plant species has not coevolved with the bird species (i.e., guava). Our results imply that the birds are not capable of generalizing HIPVs among tree species but suggest that they either learn to detect individual compounds or associate whole bouquets with food rewards.
152.
Rachel F Lane Joshua W Gatson Scott A Small Michelle E Ehrlich Sam Gandy 《Molecular neurodegeneration》2010,5(1):1-10
Background
Cultured spinal motor neurons are a valuable tool to study basic mechanisms of development, axon growth and pathfinding, and, importantly, to analyze the pathomechanisms underlying motor neuron diseases. However, the application of this cell culture model is limited by the lack of efficient gene transfer techniques which are available for other neurons. To address this problem, we have established magnetofection as a novel method for the simple and efficient transfection of mouse embryonic motor neurons. This technique allows for the study of the effects of gene expression and silencing on the development and survival of motor neurons.Results
We found that magnetofection, a novel transfection technology based on the delivery of DNA-coated magnetic nanobeads, can be used to transfect primary motor neurons. Therefore, in order to use this method as a new tool for studying the localization and transport of axonal proteins, we optimized conditions and determined parameters for efficient transfection rates of >45% while minimizing toxic effects on survival and morphology. To demonstrate the potential of this method, we have used transfection with plasmids encoding fluorescent fusion-proteins to show for the first time that the spinal muscular atrophy-disease protein Smn is actively transported along axons of live primary motor neurons, supporting an axon-specific role for Smn that is different from its canonical function in mRNA splicing. We were also able to show the suitability of magnetofection for gene knockdown with shRNA-based constructs by significantly reducing Smn levels in both cell bodies and axons, opening new opportunities for the study of the function of axonal proteins in motor neurons.Conclusions
In this study we have established an optimized magnetofection protocol as a novel transfection method for primary motor neurons that is simple, efficient and non-toxic. We anticipate that this novel approach will have a broad applicability in the study of motor neuron development, axonal trafficking, and molecular mechanisms of motor neuron diseases. 相似文献153.
Adult survival is perhaps the fitness parameter most important to population growth in long-lived species. Intrinsic and extrinsic
covariates of survival are therefore likely to be important drivers of population dynamics. We used long-term mark-recapture
data to identify genetic, individual and environmental covariates of local survival in a natural population of mountain brushtail
possums (Trichosurus cunninghami). Rainfall and intra-individual diversity at microsatellite DNA markers were associated with increased local survival of
adults and juveniles. We contrasted the performance of several microsatellite heterozygosity measures, including internal
relatedness (IR), homozygosity by loci (HL) and the mean multilocus estimate of the squared difference in microsatellite allele
sizes within an individual (mean d
2). However, the strongest effect on survival was not associated with multilocus microsatellite diversity (which would indicate
a genome-wide inbreeding effect), but a subset of two loci. This included a major histocompatibility complex (MHC)-linked
marker and a putatively neutral microsatellite locus. For both loci, diversity measures incorporating allele size information
had stronger associations with survival than measures based on heterozygosity, whether or not allele frequency information
was included (such as IR). Increased survival was apparent among heterozygotes at the MHC-linked locus, but the benefits of
heterozygosity to survival were reduced in heterozygotes with larger differences in allele size. The effect of heterozygosity
on fitness-related traits was supported by data on endoparasites in a subset of the individuals studied in this population.
There was no apparent density dependence in survival, nor an effect of sex, age or immigrant status. Our findings suggest
that in the apparent absence of inbreeding, variation at specific loci can generate strong associations between fitness and
diversity at linked markers. 相似文献
154.
Justin Maire Sam K. Girvan Sophie E. Barkla Alexis Perez-Gonzalez David J. Suggett Linda L. Blackall Madeleine J. H. van Oppen 《The ISME journal》2021,15(7):2168
Corals house a variety of microorganisms which they depend on for their survival, including endosymbiotic dinoflagellates (Symbiodiniaceae) and bacteria. While cnidarian–microorganism interactions are widely studied, Symbiodiniaceae–bacteria interactions are only just beginning to receive attention. Here, we describe the localization and composition of the bacterial communities associated with cultures of 11 Symbiodiniaceae strains from nine species and six genera. Three-dimensional confocal laser scanning and electron microscopy revealed bacteria are present inside the Symbiodiniaceae cells as well as closely associated with their external cell surface. Bacterial pure cultures and 16S rRNA gene metabarcoding from Symbiodiniaceae cultures highlighted distinct and highly diverse bacterial communities occur intracellularly, closely associated with the Symbiodiniaceae outer cell surface and loosely associated (i.e., in the surrounding culture media). The intracellular bacteria are highly conserved across Symbiodiniaceae species, suggesting they may be involved in Symbiodiniaceae physiology. Our findings provide unique new insights into the biology of Symbiodiniaceae.Subject terms: Symbiosis, Microbiome, Marine microbiology 相似文献
155.
Hzf Determines cell survival upon genotoxic stress by modulating p53 transactivation 总被引:5,自引:0,他引:5
A critical unresolved issue about the genotoxic stress response is how the resulting activation of the p53 tumor suppressor can lead either to cell-cycle arrest and DNA repair or to apoptosis. We show here that hematopoietic zinc finger (Hzf), a zinc-finger-containing p53 target gene, modulates p53 transactivation functions in an autoregulatory feedback loop. Hzf is induced by p53 and binds to its DNA-binding domain, resulting in preferential transactivation of proarrest p53 target genes over its proapoptotic target genes. Thus, p53 activation results in cell-cycle arrest in Hzf wild-type MEFs, while in Hzf(-/-) MEFs, apoptosis is induced. Exposure of Hzf null mice to ionizing radiation resulted in enhanced apoptosis in several organs, as compared to in wild-type mice. These findings provide novel insights into the regulation of p53 transactivation function and suggest that Hzf functions as a key player in regulating cell fate decisions in response to genotoxic stress. 相似文献
156.
Norton S 《Plastic and reconstructive surgery》2007,120(2):576; author reply 576
157.
Due to its ability to emit light, the luciferase from Renilla reniformis (RLuc) is widely employed in molecular biology as a reporter gene in cell culture experiments and small animal imaging. To accomplish this bioluminescence, the 37-kDa enzyme catalyzes the degradation of its substrate coelenterazine in the presence of molecular oxygen, resulting in the product coelenteramide, carbon dioxide, and the desired photon of light. We successfully crystallized a stabilized variant of this important protein (RLuc8) and herein present the first structures for any coelenterazine-using luciferase. These structures are based on high-resolution data measured to 1.4 Å and demonstrate a classic α/β-hydrolase fold. We also present data of a coelenteramide-bound luciferase and reason that this structure represents a secondary conformational form following shift of the product out of the primary active site. During the course of this work, the structure of the luciferase's accessory green fluorescent protein (RrGFP) was also determined and shown to be highly similar to that of Aequorea victoria GFP. 相似文献
158.
Hoa Tran Thanh Laurent Beney Thi Xuan Sam Nguyen Jean-Marc Belin 《生物化学与生物物理学报:生物膜》2007,1768(9):2256-2262
Linoleic acid hydroperoxide (HPOD), substrate of hydroperoxide lyase, an enzyme of the lipoxygenase pathway, can be transformed into many aromatic compounds, the so-called “green notes”. The presence of linoleic acid hydroperoxide in the culture medium of Yarrowia lipolytica, the yeast expressing the cloned hydroperoxide lyase of green bell pepper, undoubtedly exerted an inhibition on the growth and a toxic effect with 90% of yeast cells died after 120 min of exposition in 100 mM HPOD solution. The increase in cell membrane fluidity evaluated by measuring fluorescence generalized polarization with the increasing concentration of HPOD in the medium confirmed the fluidizing action of HPOD on yeast membrane. In addition, we determined by infrared spectroscopy measurement that this compound rapidly diffused into model phospholipids [1, 2-Dimyristoyl-D54-sn-Glycero-3-Phosphocholine (DMPC-D54)] bilayer, modifying their general physical state and their phase transition. In the presence of various concentrations of HPOD, the phase transition of DMPC-D54 occurred with an increase of both the corresponding wave number shift and the temperature range but the phase transition temperature was not modified. These results show that the toxic effects of HPOD on the yeast Yarrowia lipolytica may be initially linked to a strong interaction of this compound with the cell membrane phospholipids and components. 相似文献
159.
Jiang W Tran JA Tucci FC Fleck BA Hoare SR Markison S Wen J Chen CW Marinkovic D Arellano M Foster AC Chen C 《Bioorganic & medicinal chemistry letters》2007,17(23):6546-6552
A series of trans-4-phenylpyrrolidine-3-carboxamides were synthesized and characterized as potent ligands of the human melanocortin-4 receptor. Interestingly, a pair of diastereoisomers 20f-1 and 20f-2 displayed potent functional agonist and antagonist activity, respectively. Thus, the 3S,4R-compound 20f-1 possessed a K(i) of 11nM and an EC(50) of 24nM, while its 3R,4S-isomer 20f-2 exhibited a K(i) of 8.6 and an IC(50) of 65nM. Both compounds were highly selective over other melanocortin receptor subtypes. The MC4R agonist 20f-1 also demonstrated efficacy in diet-induced obese rats. 相似文献
160.
Parker MF Bronson JJ Barten DM Corsa JA Du W Felsenstein KM Guss VL Izzarelli D Loo A McElhone KE Marcin LR Padmanabha R Pak R Polson CT Toyn JH Varma S Wang J Wong V Zheng M Roberts SB 《Bioorganic & medicinal chemistry letters》2007,17(21):5790-5795
A series of amino-caprolactam sulfonamides were developed from a screening hit. Compounds with good in vitro and in vivo gamma-secretase activity are reported. 相似文献