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31.
JORDAN KARUBIAN VICTORIA L. SORK TESSA ROORDA RENATA DURÃES THOMAS B. SMITH 《Molecular ecology》2010,19(8):1745-1753
As the dominant seed dispersal agents in many ecosystems, frugivorous animals profoundly impact gene movement and fine‐scale genetic structure of plants. Most frugivores engage in some form of destination‐based dispersal, in that they move seeds towards specific destinations, resulting in clumped distributions of seeds away from the source tree. Molecular analyses of dispersed seeds and seedlings suggest that destination‐based dispersal may often yield clusters of maternal genotypes and lead to pronounced local genetic structure. The long‐wattled umbrellabird Cephalopterus penduliger is a frugivorous bird whose lek mating system creates a species‐specific pattern of seed dispersal that can potentially be distinguished from background dispersal processes. We used this system to test how destination‐based dispersal by umbrellabirds into the lek affects gene movement and genetic structure of one of their preferred food sources Oenocarpus bataua, a canopy palm tree. Relative to background dispersal processes, umbrellabird mating behaviour yielded more diverse seed pools in leks that included on average five times more seed sources and a higher incidence of long‐distance dispersal events. This resulted in markedly lower fine‐scale spatial genetic structure among established seedlings in leks than background areas. These species‐specific impacts of destination‐based dispersal illustrate how detailed knowledge of disperser behaviour can elucidate the mechanistic link driving observed patterns of seed movement and genetic structure. 相似文献
32.
Jim Waterhouse Dietmar Weinert David Minors Greg Atkinson Thomas Reilly Simon Folkard Deborah Owens Ian Macdonald Natalia Sytnik Philip Tucker 《Chronobiology international》1999,16(3):343-357
Nine healthy female subjects were studied when exposed to the natural light-dark cycle, but living for 17 “days” on a 27h day (9h sleep, 18h wake). Since the circadian endogenous oscillator cannot entrain to this imposed period, forced desynchronization between the sleep/activity cycle and the endogenous circadian temperature rhythm took place. This enabled the effects of activity on core temperature to be assessed at different endogenous circadian phases and at different stages of the sleep/activity cycle. Rectal temperature was measured at 6-minute intervals, and the activity of the nondominant wrist was summed at 1-minute intervals. Each waking span was divided into overlapping 3h sections, and each section was submitted to linear regression analysis between the rectal temperatures and the total activity in the previous 30 minutes. From this analysis were obtained the gradient (of the change in rectal temperature produced by a unit change in activity) and the intercept (the rectal temperature predicted when activity was zero). The gradients were subjected to a two-factor analysis of variance (ANOVA) (circadian phase/ time awake). There was no significant effect of time awake, but circadian phase was highly significant statistically. Post hoc tests (Newman-Keuls) indicated that gradients around the temperature peak were significantly less than those around its trough. The intercepts formed a sinusoid that, for the group, showed a mesor (±SE) of 36.97 (±0.12) and amplitude (95% confidence interval) of 0.22°C (0.12°C, 0.32°C). We conclude that this is a further method for removing masking effects from circadian temperature rhythm data in order to assess its endogenous component, a method that can be used when subjects are able to live normally. We suggest also that the decreased effect of activity on temperature when the endogenous circadian rhythm and activity are at their peak will reduce the possibility of hyperthermia. 相似文献
33.
L. I. Musatenko V. A. Berestetsky N. P. Vedenicheva V. N. Generalova G. I. Martyn K. M. Sytnik 《Biologia Plantarum》1995,37(4):553-559
Endogenous phytohormone levels and cell structure ofAcer saccharinum embryos were studied during seed development. Mature seeds had high water content (50%) and were able to germinate immediately after fruit abscission. The submicroscopic cell structure was similar to the structure of functionally active cells. Free and conjugated indole-3-acetic acid (IAA), abscisic acid (ABA), zeatin riboside and dihydrozeatin content and gibberellin-like substances (GLS) activity were determined during embryo maturation. Decrease in ABA, free IAA and cytokinin levels was observed at the end of maturation. Mature seeds contained considerable amounts of conjugated IAA and had high GLS activity. 相似文献
34.
Relationships among msx gene structure and function in zebrafish and other vertebrates 总被引:4,自引:2,他引:4
Ekker M; Akimenko MA; Allende ML; Smith R; Drouin G; Langille RM; Weinberg ES; Westerfield M 《Molecular biology and evolution》1997,14(10):1008-1022
The zebrafish genome contains at least five msx homeobox genes, msxA, msxB,
msxC, msxD, and the newly isolated msxE. Although these genes share
structural features common to all Msx genes, phylogenetic analyses of
protein sequences indicate that the msx genes from zebrafish are not
orthologous to the Msx1 and Msx2 genes of mammals, birds, and amphibians.
The zebrafish msxB and msxC are more closely related to each other and to
the mouse Msx3. Similarly, although the combinatorial expression of the
zebrafish msx genes in the embryonic dorsal neuroectoderm, visceral arches,
fins, and sensory organs suggests functional similarities with the Msx
genes of other vertebrates, differences in the expression patterns preclude
precise assignment of orthological relationships. Distinct duplication
events may have given rise to the msx genes of modern fish and other
vertebrate lineages whereas many aspects of msx gene functions during
embryonic development have been preserved.
相似文献
35.
SORAYA C M LEAL-BERTIOLI ALETÉIA V PASCOAL PATRÍCIA M GUIMARÃES MARIA F GROSSI DE SÁ REJANE L GUIMARÃES DAMARES C MONTE DAVID J BERTIOLI 《The Annals of applied biology》2003,143(3):349-357
The protein Tarin 1, from Colocasia esculenta, was expressed in Nicotiana tabacum. Bioassays were done on plants expressing Tarin 1 at different levels using Spodoptera frugiperda larvae, various bacteria and fungi and the root‐knot nematode Meloidogyne javanica. It was found that S. frugiperda larvae fed on transformed plants had retarded and lower pupation, lower accumulated biomass and higher mortality rate than larvae fed on control plants. Also, Tarin 1 was found to inhibit the growth in vitro of Pseudomonas syringae pv. tomato. For Meloidogyne javanica, both relative replication and root damage were greater in control plants than in transformed plants, but the results were not statistically significant. This work illustrates the effects of plants expressing Tarin 1, on the growth and development of insects and bacteria, and shows its potential for pest management. 相似文献
36.
The microflora of the mammary glands in the area of the nipple, the areola and the adjacent skin was studied by the methods of washings and impression. 120 nonpregnant women and 164 pregnant women were examined. The pregnant women showed a higher level of the contamination of the above-mentioned sites. The highest density of bacterial population was detected in the area of the nipple and the lowest density, on the skin surrounding the areola. Coagulase-negative staphylococci proved to be the most numerous organisms among all bacterial population found on the skin of the mammary glands of pregnant women. Of these staphylococci, S. epidermidis was most frequently isolated, its isolation rate being higher in the pregnant women than in the nonpregnant ones. 相似文献
37.
N I Zhiliaev A E Franchuk S I Sytnik A A Vorontsov I B Sen'kov 《Mikrobiologicheekij zhurnal》1991,53(2):59-62
Oxygen-peroxide-induced superweak luminescence of some microorganisms has been studied by means of the native chemiluminometer KhLM1Ts-01. It is established that total chemiluminescence decrease in the bacteria as follows: Escherichia coli----Bacillus subtilis----Proteus vulgaris----Bacillus mycoides----B. licheniformis----Pseudomonas aeruginosa----Staphylococcus epidermidis----S. aureus----Serratia marcescens----Salmonella enteritidis. A hypothesis is put forward on a possible mechanisms of appearance of the superweak luminescence of bacteria and expediency to use chemoluminometry to differentiate microorganisms. 相似文献
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40.
Longevity is a major characteristic of animals that has long fascinated scientists. In this work, we present a comprehensive database of animal longevity records and related life‐history traits entitled AnAge, which we compiled and manually curated from an extensive literature. AnAge started as a collection of longevity records, but has since been expanded to include quantitative data for numerous other life‐history traits, including body masses at different developmental stages, reproductive data such as age at sexual maturity and measurements of reproductive output, and physiological traits related to metabolism. AnAge features over 4000 vertebrate species and is a central resource for applying the comparative method to studies of longevity and life‐history evolution across the tree of life. Moreover, by providing a reference value for longevity and other life‐history traits, AnAge can prove valuable to a broad range of biologists working in evolutionary biology, ecology, zoology, physiology and conservation biology. AnAge is freely available online ( http://genomics.senescence.info/species/ ). 相似文献