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11.
Nielsen J; Peixoto AA; Piccin A; Costa R; Kyriacou CP; Chalmers D 《Molecular biology and evolution》1994,11(6):839-853
The region of the clock gene period (per) that encodes a repetitive tract
of threonine-glycine (Thr-Gly) pairs has been compared between Dipteran
species both within and outside the Drosophilidae. All the non-
Drosophilidae sequences in this region are short and present a remarkably
stable picture compared to the Drosophilidae, in which the region is much
larger and extremely variable, both in size and composition. The
accelerated evolution in the repetitive region of the Drosophilidae appears
to be mainly due to an expansion of two ancestral repeats, one encoding a
Thr-Gly dipeptide and the other a pentapeptide rich in serine, glycine, and
asparagine or threonine. In some drosophilids the expansion involves a
duplication of the pentapeptide sequence, but in Drosophila pseudoobscura
both the dipeptide and the pentapeptide repeats are present in larger
numbers. In the nondrosophilids, however, the pentapeptide sequence is
represented by one copy and the dipeptide by two copies. These observations
fulfill some of the predictions of recent theoretical models that have
simulated the evolution of repetitive sequences.
相似文献
12.
Andrea M. Quiroga Federico J. Berli Daniela Moreno Juan B. Cavagnaro Rubén Bottini 《Journal of Plant Growth Regulation》2009,28(1):28-35
In many cultivars of Vitis vinifera periods of mild water stress during ripening are thought to increase grape quality for winemaking, even though yields may
be negatively affected. Because abscisic acid (ABA) is involved in the signaling of water stress in plants, we examine the
effects of the ABA signal being given without the concomitant water stress. ABA at 250 mg l−1 was sprayed weekly or biweekly from bud-burst until harvest onto the leaves of vineyard-grown plants of cv. Cabernet Sauvignon.
For ABA-treated plants berry yield per bunch and per plant was significantly increased (1.5- to 2.0-fold) across three consecutive
harvests (2005 through 2007). Number of berries per bunch and per plant was the primary basis for the significant crop increases,
although bunches per plant also tended to increase (1.1- to 1.3-fold) across all three harvests. Other parameters assessed
included number of internodes, shoot length, leaf area, leaf water potential at midday, photosynthesis, and stomatal conductance.
These parameters showed no significant change with ABA treatment, although shoot length tended to be reduced, as was leaf
area relative to control plants. The significantly increased fruit yields were thus accomplished without accompanying increases
in leaf photosynthesis and leaf areas. Juice at harvest had equal levels of sugars (Brix) and somewhat higher levels of anthocyanins
and total polyphenols relative to control values. The two latter trends continued for the resultant wine across two vintage
years. In conclusion, three seasons of experimental trials have demonstrated that ABA application can significantly enhance
yield per plant in the field-grown grape (cv. Cabernet Sauvignon) by favoring increased berry set without diminishing the
quality of the fruit for winemaking use. 相似文献
13.
14.
Kohen W. Bauer N. Ryan McKenzie Cinzia Bottini Elisabetta Erba Sean A. Crowe 《Geobiology》2023,21(3):341-354
Oceanic Anoxic Events (OAEs) are conspicuous intervals in the geologic record that are associated with the deposition of organic carbon (OC)-rich marine sediment, linked to extreme biogeochemical perturbations, and characterized by widespread ocean deoxygenation. Mechanistic links between the marine biological carbon pump (BCP), redox conditions, and organic carbon burial during OAEs, however, remain poorly constrained. In this work we reconstructed the BCP in the western Tethys Ocean across OAE1a (~120 Mya) using sediment geochemistry and OC mass accumulation rates (OCAcc). We find that OCAcc were between 0.006 and 3.3 gC m−2 yr−1, with a mean value of 0.79 ± 0.78 SD gC m−2 yr−1—these rates are low and comparable to oligotrophic regions in the modern oceans. This challenges longstanding assumptions that oceanic anoxic events are intervals of strongly elevated organic carbon burial. Numerical modelling of the BCP, furthermore, reveals that such low OC fluxes are only possible with either or both low to moderate OC export fluxes from ocean surface waters, with rates similar to oligotrophic (nutrient-poor, <30 gC m−2 yr−1) and mesotrophic (moderate-nutrients, ~50–100 gC m−2 yr−1) regions in the modern ocean, and stronger than modern vertical OC attenuation. The low OC fluxes thus reflect a relatively weak BCP. Low to moderate productivity is further supported by palaeoecological and geochemical evidence and was likely maintained through nutrient limitation that developed in response to the burial and sequestration of phosphorus in association with iron minerals under ferruginous (anoxic iron-rich) ocean conditions. Without persistently high productivity, ocean deoxygenation during OAE1a was more likely driven by other physicochemical and biological factors including ocean warming, changes in marine primary producer community composition, and fundamental shifts in the efficiency of the BCP with associated effects and feedbacks. 相似文献
15.
Geert Zegels Geert AA Van Raemdonck Edmond P Coen Wiebren AA Tjalma Xaveer WM Van Ostade 《Proteome science》2009,7(1):17-16
Background
Cervical-vaginal fluid (CVF) plays an important role in the prevention of gynecological infections, although little is known about the contribution of CVF proteins to the immunity of the lower female genital tract. In order to analyze the protein composition of human CVF, we used CVF samples that are routinely collected during colposcopy, but are usually discarded. Since these samples are available in large quantities we aimed to analyze their usefulness for proteomics experiments. The samples were analyzed using different prefractionation techniques (ultrafiltration and C4(RP)-LC protein separation) followed by C18(RP)-LC peptide separation and identification by MALDI-TOF-TOF mass spectrometry. To determine the reproducibility of this proteomics platform we analyzed three technical replicates. Using spectral counting, protein abundances were estimated in a semiquantitative way. We also compared the results obtained in this study with those from previous studies derived from patients with different physiological conditions in order to determine an overlapping protein set. 相似文献16.
17.
Estimating medical costs with censored data 总被引:6,自引:0,他引:6
18.
Germán Murcia Mariela Pontin Herminda Reinoso Rita Baraldi Gianpaolo Bertazza Sebastián Gómez‐Talquenca Rubén Bottini Patricia N. Piccoli 《Physiologia plantarum》2016,156(3):323-337
Grape quality for winemaking depends on sugar accumulation and metabolism in berries. Abscisic acid (ABA) and gibberellins (GAs) have been reported to control sugar allocation in economically important crops, although the mechanisms involved are still unknown. The present study tested if ABA and gibberellin A3 (GA3) enhance carbon allocation in fruits of grapevines by modifying phloem loading, phloem area and expression of sugar transporters in leaves and berries. Pot‐grown Vitis vinifera cv. Malbec plants were sprayed with ABA and GA3 solutions. The amount of soluble sugars in leaves and berries related to photosynthesis were examined at three points of berry growth: pre‐veraison, full veraison and post‐veraison. Starch levels and amylase activity in leaves, gene expression of sugar transporters in leaves and berries and phloem anatomy were examined at full veraison. Accumulation of glucose and fructose in berries was hastened in ABA‐treated plants at the stage of full veraison, which was correlated with enhancement of Vitis vinifera HEXOSE TRANSPORTER 2 (VvHT2) and Vitis vinifera HEXOSE TRANSPORTER 6 (VvHT6) gene expression, increases of phloem area and sucrose content in leaves. On the other hand, GA3 increased the quantity of photoassimilates delivered to the stem thus increasing xylem growth. In conclusion, stimulation of sugar transport by ABA and GA3 to berries and stems, respectively, was due to build‐up of non‐structural carbohydrates in leaves, modifications in phloem tissue and modulation in gene expression of sugar transporters. 相似文献
19.
土壤中棉花黄萎病菌SYBR Green Ⅰ荧光RT-PCR定量检测技术研究 总被引:3,自引:0,他引:3
为实现田间土壤棉花黄萎病菌的早期检测,建立了土壤中棉花黄萎病菌的SYBR Green I荧光定量PCR检测方法。以含342bp PCR扩增产物的阳性质粒为参考,构建了标准曲线,并对该曲线的特异性、敏感性、可重复性进行了评价。结果表明,该方法具有快速、特异性强、敏感度高等特点。检测范围在3.8×103-3.8×108copies/μL之间有良好的线性关系,相关系数R2为0.996,扩增效率为101.5%,灵敏度比常规PCR方法高102倍。 相似文献
20.
Samuel J Atkinson Aleksander M Gontarczyk Abdullah AA Alghamdi Tim S Ellison Robert T Johnson Wesley J Fowler Benjamin M Kirkup Bernardo C Silva Bronwen E Harry Jochen G Schneider Katherine N Weilbaecher Mette M Mogensen Mark D Bass Maddy Parsons Dylan R Edwards Stephen D Robinson 《EMBO reports》2018,19(7)
Integrin β3 is seen as a key anti‐angiogenic target for cancer treatment due to its expression on neovasculature, but the role it plays in the process is complex; whether it is pro‐ or anti‐angiogenic depends on the context in which it is expressed. To understand precisely β3's role in regulating integrin adhesion complexes in endothelial cells, we characterised, by mass spectrometry, the β3‐dependent adhesome. We show that depletion of β3‐integrin in this cell type leads to changes in microtubule behaviour that control cell migration. β3‐integrin regulates microtubule stability in endothelial cells through Rcc2/Anxa2‐driven control of active Rac1 localisation. Our findings reveal that angiogenic processes, both in vitro and in vivo, are more sensitive to microtubule targeting agents when β3‐integrin levels are reduced. 相似文献