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51.
Variation in heat shock proteins within tropical and desert species of poeciliid fishes 总被引:8,自引:0,他引:8
Norris CE; diIorio PJ; Schultz RJ; Hightower LE 《Molecular biology and evolution》1995,12(6):1048-1062
The 70-kilodalton heat shock protein (hsp70) family of molecular
chaperones, which contains both stress-inducible and normally abundant
constitutive members, is highly conserved across distantly related taxa.
Analysis of this protein family in individuals from an outbred population
of tropical topminnows, Poeciliopsis gracilis, showed that while
constitutive hsp70 family members showed no variation in protein isoforms,
inducibly synthesized hsp70 was polymorphic. Several species of
Poeciliopsis adapted to desert environments exhibited lower levels of
inducible hsp70 polymorphism than the tropical species, but constitutive
forms were identical to those in P. gracilis, as they were in the
confamilial species Gambusia affinis. These differences suggest that
inducible and constitutive members of this family are under different
evolutionary constraints and may indicate differences in their function
within the cell. Also, northern desert species of Poeciliopsis synthesize a
subset of the inducible hsp70 isoforms seen in tropical species. This
distribution supports the theory that ancestral tropical fish migrated
northward and colonized desert streams; the subsequent decrease in
variation of inducible hsp70 may have been due to genetic drift or a
consequence of adaptation to the desert environment. Higher levels of
variability were found when the 30- kilodalton heat shock protein (hsp30)
family was analyzed within different strains of two desert species of
Poeciliopsis and also in wild-caught individuals of Gambusia affinis. In
both cases the distribution of hsp30 isoform diversity was similar to that
seen previously with allozyme polymorphisms.
相似文献
52.
Marina Yazigi Solis Simon Cooper Ruth M Hobson Guilherme G. Artioli Maria C. Otaduy Hamilton Roschel Jacques Robertson Daniel Martin Vitor S. Painelli Roger C. Harris Bruno Gualano Craig Sale 《PloS one》2015,10(4)
Objectives
Two independent studies were conducted to examine the effects of 28 d of beta-alanine supplementation at 6.4 g d-1 on brain homocarnosine/carnosine signal in omnivores and vegetarians (Study 1) and on cognitive function before and after exercise in trained cyclists (Study 2).Methods
In Study 1, seven healthy vegetarians (3 women and 4 men) and seven age- and sex-matched omnivores undertook a brain 1H-MRS exam at baseline and after beta-alanine supplementation. In study 2, nineteen trained male cyclists completed four 20-Km cycling time trials (two pre supplementation and two post supplementation), with a battery of cognitive function tests (Stroop test, Sternberg paradigm, Rapid Visual Information Processing task) being performed before and after exercise on each occasion.Results
In Study 1, there were no within-group effects of beta-alanine supplementation on brain homocarnosine/carnosine signal in either vegetarians (p = 0.99) or omnivores (p = 0.27); nor was there any effect when data from both groups were pooled (p = 0.19). Similarly, there was no group by time interaction for brain homocarnosine/carnosine signal (p = 0.27). In study 2, exercise improved cognitive function across all tests (P<0.05), although there was no effect (P>0.05) of beta-alanine supplementation on response times or accuracy for the Stroop test, Sternberg paradigm or RVIP task at rest or after exercise.Conclusion
28 d of beta-alanine supplementation at 6.4g d-1 appeared not to influence brain homocarnosine/carnosine signal in either omnivores or vegetarians; nor did it influence cognitive function before or after exercise in trained cyclists. 相似文献53.
Sonia Altizer Keith A. Hobson Andrew K. Davis Jacobus C. De Roode Leonard I. Wassenaar 《PloS one》2015,10(11)
Long-distance migration can lower parasite prevalence if strenuous journeys remove infected animals from wild populations. We examined wild monarch butterflies (Danaus plexippus) to investigate the potential costs of the protozoan Ophryocystis elektroscirrha on migratory success. We collected monarchs from two wintering sites in central Mexico to compare infection status with hydrogen isotope (δ
2H) measurements as an indicator of latitude of origin at the start of fall migration. On average, uninfected monarchs had lower δ
2H values than parasitized butterflies, indicating that uninfected butterflies originated from more northerly latitudes and travelled farther distances to reach Mexico. Within the infected class, monarchs with higher quantitative spore loads originated from more southerly latitudes, indicating that heavily infected monarchs originating from farther north are less likely to reach Mexico. We ruled out the alternative explanation that lower latitudes give rise to more infected monarchs prior to the onset of migration using citizen science data to examine regional differences in parasite prevalence during the summer breeding season. We also found a positive association between monarch wing area and estimated distance flown. Collectively, these results emphasize that seasonal migrations can help lower infection levels in wild animal populations. Our findings, combined with recent declines in the numbers of migratory monarchs wintering in Mexico and observations of sedentary (winter breeding) monarch populations in the southern U.S., suggest that shifts from migratory to sedentary behavior will likely lead to greater infection prevalence for North American monarchs. 相似文献
54.
Diana Solovyeva Jason Newton Keith Hobson James W. Fox Vsevolod Afanasyev Anthony D. Fox 《Ibis》2014,156(2):466-471
Scaly‐sided Mergansers Mergus squamatus breed on freshwater rivers in far eastern Russia, Korea and China, wintering in similar habitats in China and Korea, but nothing was known of their moulting habitat. To investigate the moult strategies of this species, we combined wing feather stable isotope ratios (males and females) with geolocator data (nesting females) to establish major habitat types (freshwater, brackish or saltwater) used by both sexes during wing moult. Although most Scaly‐sided Mergansers of both sexes probably moult on freshwater, some males and non‐breeding and failed breeding females appeared to undertake moult migration to brackish and marine waters. Given the previous lack of any surveys of coastal or estuarine waters for this species during the moult period, these findings suggest important survey needs for the effective conservation of the species during the flightless moult period. 相似文献
55.
Birds migrating annually to high‐latitude breeding grounds may benefit from the transport of endogenous nutrient reserves that ultimately contribute to reproduction. Shorebirds represent a diverse group of Arctic breeders that typically arrive on the breeding grounds with body reserves enriched in 13C and 15N due to wintering and staging in marine or estuarine habitats. Such isotopic differences between endogenous macronutrient reserves and local foodwebs allow the use of stable isotopes to test for the source of nutrient allocations to eggs. We examined δ13C and δ15N values in lipid‐free yolk and albumen and δ13C values in yolk lipid of first clutches of ten species of sandpiper and plover breeding near Churchill, Manitoba, Canada in 2003. Most birds had egg isotope values indicating a C3 terrestrial biome, which fits primarily an income (exogenous) breeding strategy. Two exceptions were single sandpiper and plover with strong marine isotope values. Among species, strong positive relationships for each isotope between egg tissue components suggest that egg proteins and lipids tended to be derived from the same isotopic source. Correlations of egg δ13C values for lipids and proteins approached theoretical relationships expected for exogenous breeding strategies, based on captive studies. Significant positive correlations between clutch initiation date and δ13C values of egg lipids and albumen suggest some endogenous nutrient contributions to later laid eggs but the circumstances under which this may occur are unstudied. Where possible, we recommend that researchers use blood and fat biopsies from laying females as a means of anchoring endogenous and exogenous endpoints for modeling of each reproductive event. We encourage the isotopic analysis of egg albumen, yolk and yolk lipids among individuals and species and tests of correlations among these components as a means of inferring origins of nutrients to eggs. 相似文献
56.
Predators and parasites commonly use chemical cues associated with herbivore feeding and reproduction to locate prey. However,
we currently know little about mechanisms by which herbivores may avoid such natural enemies. Pheromones are crucial to many
aspects of herbivore life history, so radical alterations of these compounds could be disadvantageous despite their exploitation
by predators. Instead, minor modifications in pheromone chemistry may facilitate partial escape while maintaining intraspecific
functionality. We tested this hypothesis using Ips pini, an endophytic beetle that develops in the phloem tissue of pine trees. Its predominant predators in the Great Lakes region
of North America are Thanasimus dubius and Platysoma cylindrica, both of which are highly attracted to I. pini’s pheromones. However, there are significant disparities between prey and predator behaviors that relate to nuances of pheromone
chemistry. Thanasimus dubius is most attracted to the (+) stereoisomer of ipsdienol, and P. cylindrica is most attracted to the (−) form; Ips pini prefers racemic mixtures intermediate between each predator’s preferences. Further, a component that is inactive by itself,
lanierone, greatly synergizes the attraction of I. pini to ipsdienol, but has a weak or no effect on its predators. A temporal component adds to this behavioral disparity: lanierone
is most important in the communication of I. pini during periods when its predators are most abundant. The difficulties involved in tracking prey are further compounded by
spatial and temporal variation in prey signaling on a local scale. For example, the preferences of I. pini vary significantly among sites only 50 km apart. This chemical crypsis is analogous to morphological forms of camouflage,
such as color and mimicry, that are widely recognized as evasive adaptations against visually searching predators. Presumably
these relationships are dynamic, with predators and prey shifting responses in microevolutionary time. However, several factors
may delay predator counter adaptations. The most important appears to be the availability of alternate prey, specifically
I. grandicollis, whose pheromone ipsenol is highly attractive to the above predators but not cross-attractive with I. pini. Consistent with this view, the specialist parasitoid, Tomicobia tibialis, has behavioral preferences for pheromone components that closely correspond with those of I. pini. These results are discussed in terms of population dynamics and coevolutionary theory.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
57.
Quantitative chemical proteomics reveals mechanisms of action of clinical ABL kinase inhibitors 总被引:8,自引:0,他引:8
Bantscheff M Eberhard D Abraham Y Bastuck S Boesche M Hobson S Mathieson T Perrin J Raida M Rau C Reader V Sweetman G Bauer A Bouwmeester T Hopf C Kruse U Neubauer G Ramsden N Rick J Kuster B Drewes G 《Nature biotechnology》2007,25(9):1035-1044
We describe a chemical proteomics approach to profile the interaction of small molecules with hundreds of endogenously expressed protein kinases and purine-binding proteins. This subproteome is captured by immobilized nonselective kinase inhibitors (kinobeads), and the bound proteins are quantified in parallel by mass spectrometry using isobaric tags for relative and absolute quantification (iTRAQ). By measuring the competition with the affinity matrix, we assess the binding of drugs to their targets in cell lysates and in cells. By mapping drug-induced changes in the phosphorylation state of the captured proteome, we also analyze signaling pathways downstream of target kinases. Quantitative profiling of the drugs imatinib (Gleevec), dasatinib (Sprycel) and bosutinib in K562 cells confirms known targets including ABL and SRC family kinases and identifies the receptor tyrosine kinase DDR1 and the oxidoreductase NQO2 as novel targets of imatinib. The data suggest that our approach is a valuable tool for drug discovery. 相似文献
58.
Space‐time tradeoffs in the development of precipitation‐based isoscape models for determining migratory origin 下载免费PDF全文
Hannah B. Vander Zanden Michael B. Wunder Keith A. Hobson Steven L. Van Wilgenburg Leonard I. Wassenaar Jeffrey M. Welker Gabriel J. Bowen 《Journal of avian biology》2015,46(6):658-667
Precipitation stable isotope patterns over continental scales provide a fundamental tool for tracking origins of migratory species. Hydrogen isotopes from rain and environmental waters are assimilated into animal tissues and may thereby reveal the location where tissues were synthesized. Predictive isotopic maps (or isoscapes) of stable hydrogen isotope values in precipitation (δ2Hp) are typically generated by time‐averaging observations from a global network of stations that have been sampled irregularly in space and time. We previously demonstrated that restricting the temporal range in δ2Hp isoscapes to biologically relevant time frames did not improve predictions of geographic origin for two migratory species in North America and Europe; rather, it decreased the accuracy of assignment. Here, we examined whether the reduction in assignment accuracy stemmed from a decrease in the number of sampling stations available to support isoscape development for shorter time periods. Multiple regression models were used to predict the hydrogen isotope composition in precipitation using isotopic measurements from each station along with a suite of independent variables. The reduction in the number of stations with δ2Hp measurements used to estimate isoscape model parameters did not alter the accuracy and precision of assignments consistently. We also examined accuracy across a range of reduced station numbers and found that mean accuracy was affected only at very low numbers of stations, indicating that the spatial isotopic patterns in precipitation that are useful for assignment applications can be characterized with data from relatively limited data stations. The number and spatial distribution of stations may have more influence when geostatistical models are used to generate isoscapes, as they incorporate spatial correlation in the dataset. The results can be used to guide future research in understanding how data availability and constraints in creating δ2Hp isoscapes may affect predictions of geographic origins. 相似文献
59.
Kyle A. Cutting Keith A. Hobson Jay J. Rotella Jeffrey M. Warren Susan E. Wainwright‐de la Cruz John Y. Takekawa 《Journal of avian biology》2011,42(6):505-513
Lesser scaup Aythya affinis populations have declined throughout the North American continent for the last three decades. It has been hypothesized that the loss and degradation of staging habitats has resulted in reduced female body condition on the breeding grounds and a concomitant decline in productivity. We explored the importance of body (endogenous) reserves obtained prior to arrival on the breeding ground in egg protein formation in southwestern Montana during 2006–2008 using stable‐carbon (δ13C) and nitrogen (δ15N) isotope analyses of scaup egg components, female tissue, and local prey items. From arrival on the breeding grounds through the egg‐laying period, δ15N values of scaup red blood cells decreased while δ13C values became less variable; a pattern consistent with endogenous tissues equilibrating with local (freshwater) dietary sources. In 2006 and 2008, isotopic values for egg albumen and yolk protein indicated that most (>90%) protein used to produce these components was obtained on the breeding grounds. However, in 2007, a year with an exceptionally warm and dry spring, endogenous reserves contributed on average 41% of yolk and 29% of albumen. Results from this study suggest that female scaup can meet the protein needs of egg production largely from local dietary food sources. This highlights the importance of providing high‐quality breeding habitats for scaup. Whether this pattern holds in areas with similar breeding season lengths but longer migration routes, such as those found in the western boreal forest, should be investigated. 相似文献
60.