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1.
Cerumen, or propolis, is a mixture of plant resins enriched with bee secretions. In Australia, stingless bees are important
pollinators that use cerumen for nest construction and possibly for colony’s health. While extensive research attests to the
therapeutic properties of honeybee (Apis mellifera) propolis, the biological and medicinal properties of Australian stingless bee cerumen are largely unknown. In this study,
the chemical and biological properties of polar extracts of cerumen from Tetragonula carbonaria in South East Queensland, Australia were investigated using gas chromatography-mass spectrometry (GC-MS) analyses and in
vitro 5-lipoxygenase (5-LOX) cell-free assays. Extracts were tested against comparative (commercial tincture of A. mellifera propolis) and positive controls (Trolox and gallic acid). Distinct GC-MS fingerprints of a mixed diterpenic profile typical
of native bee cerumen were obtained with pimaric acid (6.31 ± 0.97%, w/w), isopimaric acid (12.23 ± 3.03%, w/w), and gallic
acid (5.79 ± 0.81%, w/w) tentatively identified as useful chemical markers. Characteristic flavonoids and prenylated phenolics
found in honeybee propolis were absent. Cerumen extracts from T. carbonaria inhibited activity of 5-LOX, an enzyme known to catalyse production of proinflammatory mediators (IC50 19.97 ± 2.67 μg/ml, mean ± SEM, n = 4). Extracts had similar potency to Trolox (IC50 12.78 ± 1.82 μg/ml), but were less potent than honeybee propolis (IC50 5.90 ± 0.62 μg/ml) or gallic acid (IC50 5.62 ± 0.35 μg/ml, P < 0.001). These findings warrant further investigation of the ecological and medicinal properties of this stingless bee cerumen,
which may herald a commercial potential for the Australian beekeeping industry. 相似文献
2.
The effect of different ambient sulphide concentrations on the internal pH regime of Hediste (Nereis) diversicolor was studied under in vivo conditions using liquid membrane pH microelectrodes, a method which is new to marine sciences.
As a case study, the hypothesis was tested whether organisms exposed to ambient sulphidic conditions are able to lower their
internal pH which, in effect, would reduce sulphide influx into the animals and thus could represent an effective detoxification
mechanism. It was shown that a significant lowering of the internal pH occurred within only 20 min after adding sulphide.
This pH lowering appeared to be dependent on the external sulphide concentration of the ambient medium and showed a saturation
beyond a threshold level of about 130 μM. It is discussed whether this sulphide-induced pH drop is an active regulatory mechanism
and acts as an effective protection mechanism against sulphide during short-term exposures.
Received: 1 June 1999 / Accepted in revised form: 3 May 2000 相似文献
3.
The bathymetric distribution of marine benthic invertebrates is likely governed by a combination of ecological and physiological
factors. The present study investigates oxygen consumption and heartbeat rate in response to attempted feeding at 1, 100 and
150 atm in the shallow-water spider crab, Maja brachydactyla, from temperate European waters. No significant difference was evident between the resting heartbeat rate of specimens at
1 or 100 atm, which were 56 and 65 bpm, respectively (Mann–Whitney, U = 5382.0; n = 95, 98; p = 0.079). However, at 150 atm the resting heartbeat rate was significantly higher than that observed for 100 atm at 108 bpm
(Mann–Whitney, U = 149.0; n = 45, 98; p < 0.001). At 150 atm, feeding was never observed and coupled with the elevated resting heartbeat rate; it is suggested by
150 atm continued survival is unfeasible. At 1 and 100 atm, feeding instigated a distinct increase in heartbeat rate, which
remained elevated for over 30 h. This increase peaked within 1 h at 1 atm. At 100 atm, this required 4 h and postprandial
oxygen consumption was significantly higher than at 1 atm (Kruskal–Wallis, H = 85.036; df = 2; p < 0.001). Elevated hydrostatic pressure is hypothesized to extend the duration and the total metabolic energy devoted to
specific dynamic action. The metabolic requirements of feeding under hyperbaric conditions may even reach such a critical
demand that feeding is entirely inhibited. 相似文献
4.
Marcelo Perantoni Darci M. S. Esquivel Eliane Wajnberg Daniel Acosta-Avalos Geraldo Cernicchiaro Henrique Lins de Barros 《Die Naturwissenschaften》2009,96(6):685-690
Magnetotactic microorganisms use the interaction of internal biomineralized nanoparticles with the geomagnetic field to orientate.
The movement of the magnetotactic multicellular prokaryote Candidatus Magnetoglobus multicellularis under an applied magnetic field was observed. A method using digital image processing techniques
was used to track the organism trajectory to simultaneously obtain its body radius, velocity, U-turn diameter, and the reorientation
time. The magnetic moment was calculated using a self-consistent method. The distribution of magnetic moments and radii present
two well-characterized peaks at (9 ± 2) × 10−15 and (20 ± 3) × 10−15 A m2 and (3.6 ± 0.1) and (4.3 ± 0.1) μm, respectively. For the first time, simultaneous determination of the distribution of the
organism radii and magnetic moment was obtained from the U-turn method by a new digital imaging processing. The bimodal distributions
support an organism reproduction process model based on electron microscopy observations. These results corroborate the prokaryote
multicellular hypothesis for Candidatus M. multicellularis. 相似文献
5.
Laura Rodríguez-Loeches Alejandro Barro Martha Pérez Frank Coro 《Die Naturwissenschaften》2009,96(4):531-536
Both sexes of Phoenicoprocta capistrata have functional tymbals. The scanning electron microscopy revealed differences in the morphology of these organs in males
and females. Male tymbals have a well-developed striated band, constituted by 21 ± 2 regularly arranged striae whereas female
tymbals lack a striated band. This type of sexual dimorphism is rare in Arctiidae. The recording of the sound produced by
moths held by the wings revealed that while males produced trains of pulses organized in modulation cycles, females produced
clicks at low repetition rate following very irregular patterns. Statistically, there are differences between sexes in terms
of the duration of pulses, which were 355 ± 24 μs in the case of males and 289 ± 29 μs for females. The spectral characteristics
of the pulses also show sexual dimorphism. Male pulses are more tuned (Q
10 = 5.2 ± 0.5) than female pulses (Q
10 = 2.7 ± 0.5) and have a higher best frequency (42 ± 1 kHz vs. 29 ± 2 kHz). To our knowledge, this is the first report on
an arctiid moth showing sexual dimorphism in tymbal’s anatomy that leads to a best frequency dimorphism. Males produce sound
at mating attempts. The sounds recorded during mating are modulation cycles with the same spectral characteristics as those
recorded when males are held by the wings. The morphological and acoustic features of female tymbals could indicate a process
of degeneration and adaptation to conditions under which the emission of complex patterns is not necessary.
Frank Coro no longer works at Universidad de La Habana. 相似文献
6.
Stephan Baumgartner Martin Wolf Peter Skrabal Felix Bangerter Peter Heusser André Thurneysen Ursula Wolf 《Die Naturwissenschaften》2009,96(9):1079-1089
Quantitative meta-analyses of randomized clinical trials investigating the specific therapeutic efficacy of homeopathic remedies
yielded statistically significant differences compared to placebo. Since the remedies used contained mostly only very low
concentrations of pharmacologically active compounds, these effects cannot be accounted for within the framework of current
pharmacology. Theories to explain clinical effects of homeopathic remedies are partially based upon changes in diluent structure.
To investigate the latter, we measured for the first time high-field (600/500 MHz) 1H T1 and T2 nuclear magnetic resonance relaxation times of H2O in homeopathic preparations with concurrent contamination control by inductively coupled plasma mass spectrometry (ICP-MS).
Homeopathic preparations of quartz (10c–30c, n = 21, corresponding to iterative dilutions of 100−10–100−30), sulfur (13x–30x, n = 18, 10−13–10−30), and copper sulfate (11c–30c, n = 20, 100−11–100−30) were compared to n = 10 independent controls each (analogously agitated dilution medium) in randomized and blinded experiments. In none of the
samples, the concentration of any element analyzed by ICP-MS exceeded 10 ppb. In the first measurement series (600 MHz), there
was a significant increase in T1 for all samples as a function of time, and there were no significant differences between homeopathic potencies and controls.
In the second measurement series (500 MHz) 1 year after preparation, we observed statistically significant increased T1 relaxation times for homeopathic sulfur preparations compared to controls. Fifteen out of 18 correlations between sample
triplicates were higher for controls than for homeopathic preparations. No conclusive explanation for these phenomena can
be given at present. Possible hypotheses involve differential leaching from the measurement vessel walls or a change in water
molecule dynamics, i.e., in rotational correlation time and/or diffusion. Homeopathic preparations thus may exhibit specific
physicochemical properties that need to be determined in detail in future investigations.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
7.
Gerhard Gries Regine Gries Paul W. Schaefer Tadao Gotoh Yasutomo Higashiura 《Die Naturwissenschaften》1999,86(5):235-238
Pheromone extract of female pink gypsy moth, Lymantria mathura, was analyzed by coupled gas chromatographic-electroantennographic detection (GC-EAD) and coupled GC-mass spectrometry (MS),
employing fused silica columns coated with DB-5, DB-210, or DB-23 and a custom-made GC column that separated enantiomers of
unsaturated epoxides. These analyses revealed (9R,10S)-cis–9,10-epoxy-Z3,Z6-nonadecadiene [termed here (+)-mathuralure] and (9S,10R)-cis–9,10-epoxy-Z3,Z6-nonadecadiene [termed here (–)-mathuralure] at a 1 : 4 ratio as major candidate pheromone components. In field experiments
in northern Japan (Morioka, Iwate Prefecture and Bibai, Hokkaido Prefecture), (+)- and (–)-mathuralure at a ratio of 1 : 4,
but not 1 : 1 or singly, were attractive to male L. mathura. This is the first demonstration that attraction of male moths required the very same ratio of pheromone enantiomers as produced
by conspecific females. Whether L. mathura employ different blend ratios in different geographic areas, and the role of five additional candidate pheromone components
identified in this study remains to be investigated.
Received: 29 October 1998 / Accepted in revised form: 29 December 1998 相似文献
8.
During reproductive migration the electroreceptive African sharptooth catfish, Clarias gariepinus (Siluriformes), preys mainly on a weakly electric fish, the bulldog Marcusenius macrolepidotus (Mormyridae; Merron 1993). This is puzzling because the electric organ discharges of known Marcusenius species are pulses of a duration (<1 ms) too short for being detected by the catfishes' low-frequency electroreceptive system
(optimum sensitivity, 10–30 Hz; Peters and Bretschneider 1981). On the recent discovery that M. macrolepidotus males emit discharges lasting approximately ten times longer than those of females (Kramer 1997a) we determined behavioral
thresholds for discharges of both sexes, using synthetic playbacks of field-recorded discharges. C. gariepinus detected M. macrolepidotus male discharges down to a field gradient of 103 μVpeak-peak/cm and up to a distance of 1.5 m at natural field conditions. In contrast, thresholds for female discharges were not reached
with our setup, and we presume the bulldogs eaten by catfish are predominantly male.
Received: 7 October 1998 / Accepted in revised form: 29 December 1998 相似文献
9.
Fruits of Garden Lettuce, imbibed in 0.01 M KNO3, were depleted of maternal active phytochrome B by saturating deep-red exposure and photosensitized by chilling for 1 week
at 4 °C. Twenty saturated fluence-response curves for photoinduced germination were elaborated between 300 and 800 nm, using
exposure periods from 6 to 600 s at 22.5 °C; there is linear and closely parallel regression in the logarithmic probability
net. The reciprocals of the half-response fluences obtained gave the apparent conversion spectrum of the controlling pigments
and this was corrected for the transmittance of the seed-coat. It is a phytochrome spectrum of P
r with photoconversion cross-sections of 1.2·109 and 4.5·103 m2 mol–1 at 666 and 800 nm, respectively. This means that for half-saturated germination of sensitized seed, fewer than 1 out of 200,000
phytochrome A molecules have to be photoconverted to P
fr, and no photo-reversibility by deep-red was found. Therefore, all spectral colours of nightly moon- or skylight should stimulate
the germination of sensitized weed seeds if they are exposed at the soil surface between sequential tillage operations.
Received: 28 April 2000 / Accepted in revised form: 28 July 2000 相似文献
10.
Lu Y Beeman RW Campbell JF Park Y Aikins MJ Mori K Akasaka K Tamogami S Phillips TW 《Die Naturwissenschaften》2011,98(9):755-761
We report that the abdominal epidermis and associated tissues are the predominant sources of male-produced pheromones in the
red flour beetle, Tribolium castaneum and, for the first time, describe the stereoisomeric composition of the natural blend of isomers of the aggregation pheromone
4,8-dimethyldecanal (DMD) in this important pest species. Quantitative analyses via gas chromatography–mass spectrometry showed
that the average amount of DMD released daily by single feeding males of T. castaneum was 878 ± 72 ng (SE). Analysis of different body parts identified the abdominal epidermis as the major source of aggregation
pheromone; the thorax was a minor source, while no DMD was detectable in the head. No internal organs or obvious male-specific
glands were associated with pheromone deposition. Complete separation of all four stereoisomers of DMD was achieved following
oxidation to the corresponding acid, derivatization with (1R, 2R)- and (1S, 2S)-2-(anthracene-2,3-dicarboximido)cyclohexanol to diastereomeric esters, and their separation on reversed-phase high-performance
liquid chromatography at −54°C. Analysis of the hexane eluate from Porapak-Q-collected volatiles from feeding males revealed
the presence of all four isomers (4R,8R)/(4R,8S)/(4S,8R)/(4S,8S) at a ratio of approximately 4:4:1:1. A walking orientation bioassay in a wind tunnel with various blends of the four synthetic
isomers further indicated that the attractive potency of the reconstituted natural blend of 4:4:1:1 was equivalent to that
of the natural pheromone and greater than that of the 1:1 blend of (4R,8R)/(4R,8S) used in commercial lures. 相似文献
11.
Torpor is an energy-saving mechanism that allows endotherms to overcome energetic challenges. Torpor should be avoided during
reproduction because of potential incompatibility with offspring growth. To test if torpor can be used during gestation and
lactation to compensate for food shortage, we exposed reproductive female grey mouse lemurs (Microcebus murinus), a heterothermic primate, to different levels of food availability. Torpor use was characterised by daily skin temperature
profiles, and its energetic outcome was assessed from changes in body mass. Food shortage triggered torpor during the end
of the gestation period (n = 1), ranging from shallow in response to 40% food restriction to deep daily torpor in response to 80% restriction. During
the early period of lactation, females fed ad libitum (n = 2) or exposed to a 40% restriction (n = 4) remained normothermic; but 80% food restricted females (n = 5) gave priority to energy saving, increasing the frequency and depth of torpor bouts. The use of torpor was insufficient
to compensate for 80% energetic shortage during lactation resulting in loss of mass from the mother and delayed growth in
the pups. This study provides the first evidence that a heterothermic primate can use torpor to compensate for food shortages
even during reproduction. This physiological flexibility likely evolved as a response to climate-driven fluctuations in food
availability in Madagascar. 相似文献
12.
Reversed sex change by widowed males in polygynous and protogynous fishes: female removal experiments in the field 总被引:1,自引:0,他引:1
Sex change, either protogyny (female to male) or protandry (male to female), is well known among fishes, but evidence of bidirectional
sex change or reversed sex change in natural populations is still very limited. This is the first report on female removal
experiments for polygnous and protogynous fish species to induce reversed sex change in the widowed males in the field. We
removed all of the females and juveniles from the territories of dominant males in the cleaner wrasse Labroides dimidiatus (Labridae) and the rusty angelfish Centropyge ferrugata (Pomacanthidae) on the coral reefs of Okinawa. In both species, if new females or juveniles did not immigrate into the territories
of the widowed males, some of them emigrated to form male–male pairs. When a male–male pair formed, the smaller, subordinate
partner began to perform female sexual behaviours (n = 4 in L. dimidiatus; n = 2 in C. ferrugata) and, finally, released eggs (n = 1, respectively). Thus, the reversed sex change occurred in the widowed males according to the change of their social status.
These results suggest that such female removal experiments will contribute to the discovery of reversed sex change in the
field also in other polygnous and protogynous species. 相似文献
13.
Humin, the most recalcitrant and abundant organic fraction of soils and of sediments, is a significant contributor to the
stable carbon pool in soils and is important for the global carbon budget. It has significant resistance to transformations
by microorganisms. Based on the classical operational definition, humin can include any humic-type substance that is not soluble
in water at any pH. We demonstrate in this study how sequential exhaustive extractions with 0.1 M sodium hydroxide (NaOH) + 6 M
urea, followed by dimethylsulphoxide (DMSO) + 6% (v/v) sulphuric acid (H2SO4) solvent systems, can extract 70–80% of the residual materials remaining after prior exhaustive extractions in neutral and
aqueous basic media. Solid-state 13C NMR spectra have shown that the components isolated in the base + urea system were compositionally similar to the humic
and fulvic acid fractions isolated at pH 12.6 in the aqueous media. The NMR spectra indicated that the major components isolated
in the DMSO + H2SO4 medium had aliphatic hydrocarbon associated with carboxyl functionalities and with lesser amounts of carbohydrate and peptide
and minor amounts of lignin-derived components. The major components will have significant contributions from long-chain fatty
acids, waxes, to cuticular materials. The isolates in the DMSO + H2SO4 medium were compositionally similar to the organic components that resisted solvation and remained associated with the soil
clays. It is concluded that the base + urea system released humic and fulvic acids held by hydrogen bonding or by entrapment
within the humin matrix. The recalcitrant humin materials extracted in DMSO + H2SO4 are largely biological molecules (from plants and the soil microbial population) that are likely to be protected from degradation
by their hydrophobic moieties and by sorption on the soil clays. Thus, the major components of humin do not satisfy the classical
definitions for humic substances which emphasise that these arise from microbial or chemical transformations in soils of the
components of organic debris. 相似文献
14.
Although turbidite deposits are classically considered to be good reservoir rocks for oil and gas, there are no reports concerning
their source rock potential in the literature. The sediments from the Vallfogona Formation in the South-Eastern Pyrenees present
numerous organic matter-rich levels interbedded in sandstones and coarse turbidite deposits. Two types of organic matter deposits
were differentiated on the basis of organic geochemistry and petrography: type A and type B. Type A was deposited in a carbonate
marine environment under hypersaline conditions as indicated mainly by even/odd n-alkane predominance, pristane and phytane ratio (Pr/Ph) < 1, presence of gammacerane, and trisnorneohopane over trisnorhopane
ratio (Ts/Tm) > 1. Type B was deposited in a more mud-rich marine environment evidenced by the predominance of odd n-alkane, Pr/Ph ≥ 1, Ts/Tm < 1, the absence of gammacerane, similar concentrations of the C27 and C29 regular steranes, and the greater abundance of C27 diasteranes. Turbidite facies can be regarded as an environment where organic matter sedimentation is heterogeneous in type
and amount. This study suggests that turbidite deposits with interbedded organic matter-rich levels may act as a combined
source–reservoir system. 相似文献
15.
Xiaoming Xu Jie Tang Zhaoyang Li Chang Liu Weizheng Han 《Mitigation and Adaptation Strategies for Global Change》2011,16(6):721-731
In this study, paddy fields in Jilin province which are flooded parcel of arable lands used for growing rice (Oryza sativa Linn.) were selected as the object. Long-term exploitation of paddy fields led to variations of soil organic carbon (SOC) and green
house gases (GHGs) emissions which might contribute to global warming. In order to calculate the amount of global warming
potentials (GWPs) of emissions from ricepaddies and find the correlations among rice yield, SOC storage and GWP, DeNitrification-DeComposition
(DNDC) model was used to simulate SOC densities and fluxes of main GHGs emitted from paddy fields. After verification, simulation
results were used to calculate SOC storages and 100-year GWPs from 1949 to 2009. Results indicated that SOC densities in depths
of 0–10 cm, 10–20 cm and 20–30 cm all kept increasing. Average methane (CH4) and nitrous oxide (N2O) fluxes were 278.55 kg carbon (kgC) ha−1 a−1 and 2.22 kg nitrogen (kgN) ha−1 a−1. The SOC storage (0–30 cm) had increased from 3.96 × 109kgC in 1949 to 47.85 × 109kgC in 2009. In addition, GWP emission was increasing exponentially in the past 61 years, from 0.16 × 106 Mg carbon dioxide equivalents (CO2-equivalents) to 66.36 × 106 Mg CO2-equivalents. Both SOC storage and GWP presented obviously linear relation to rice yields. Overall, the research suggested
that long-term rice yields could be used to estimate the SOC storage and GWP variations. 相似文献
16.
Wassgren AB Bergström G Sierpinski A Anderbrant O Högberg HE Hedenström E 《Die Naturwissenschaften》2000,87(1):24-29
The main component of the sex pheromone precursor in females of Macrodiprion nemoralis was identified as a threo-3,7,9-trimethyl-2-tridecanol isomer, approximately 800 pg per female, by gas chromatography–mass spectrometry. Comparison
of mass spectrometric ion chromatograms showed that the natural compound in the female extract has the same retention time
and mass spectrum as one of the two synthetic threo peaks. The acetate of the synthetic 16-isomer mixture caught a large number
of males in the field, confirming the structure of the active pheromone. Comparison of gas chromatograms of the natural female
extract with the eight synthetic threo stereoisomers showed that the pheromone is the (2S,3R,7R,9S)-stereoisomer of 3,7,9-trimethyl-2-tridecyl acetate.
Received: 12 May 1999 / Accepted in revised form: 16 September 1999 相似文献
17.
This paper reports study of day-to-day instability in the locomotor activity rhythm of the nocturnal field mouse Mus booduga. The free-running period (τ) of this rhythm was estimated in constant darkness in n=347 adult male mice. The "onset" and "offset" of locomotor activity rhythm were used as phase markers of the circadian clock.
The precision of the onset of locomotor activity was observed to be a non-linear function of τ, with maximal precision at
τ close to 24 h. The precision of the offset of locomotor activity was found to increase with increasing τ. These results
suggest that the homeostasis of τ is tighter when τ is close to 24 h.
Received: 5 May 1998 / Accepted: 11 February 1999 相似文献
18.
Numerical dating of the Eckfeld maar fossil site, Eifel, Germany: a calibration mark for the Eocene time scale 总被引:1,自引:0,他引:1
Sediments of the Eckfeld maar (Eifel, Germany) bear a well-preserved Eocene fauna and flora. Biostratigraphically, Eckfeld
corresponds to the Middle Eocene mammal reference level MP (Mammals Paleogene) 13 of the ELMA (European Land Mammal Age) Geiseltalian.
In the maar crater, basalt fragments were drilled, representing explosion crater eruption products. By 40Ar/39Ar dating of the basalt, for the first time a direct numerical calibration mark for an Eocene European mammal locality has
been established. The Eckfeld basalt inverse isochron date of 44.3±0.4 Ma suggests an age for the Geiseltalian/Robiacian boundary
at 44 Ma and, together with the 1995 time scale of Berggren et al., a time span ranging from 49 to 44 Ma for the Geiseltalian
and from 44 to 37 Ma for the Robiacian, respectively. Additional 40Ar/39Ar dating on a genetically related basalt occurrence close to the maar confirms a period of volcanism of ca. 0.6 m.y. in the
Eckfeld area, matching the oldest Eocene volcanic activity of the Hocheifel volcanic field.
Received: 27 December 1999 / Accepted in revised form: 6 April 2000 相似文献
19.
Fisher CR MacDonald IR Sassen R Young CM Macko SA Hourdez S Carney RS Joye S McMullin E 《Die Naturwissenschaften》2000,87(4):184-187
During a research cruise in July 1997 in the Gulf of Mexico we discovered a gas hydrate approximately 1 m thick and over
2 m in diameter which had recently breached the sea floor at a depth of 540 m. The hydrate surface visible from the submarine
was considerably greater than that of any other reported hydrate. Two distinct color bands of hydrate were present in the
same mound, and the entire exposed surface of the hydrate was infested (2500 individuals/m2) with 2 to 4 cm-long worms, since described as a new species, Hesiocaeca
methanicola, in the polychaete family Hesionidae (Desbruyères and Toulmond 1998). H.
methanicola tissue stable isotope values are consistent with a chemoautotrophic food source. No evidence of chemoautotrophic symbionts
was detected, but geochemical data support the presence of abundant free living bacteria on the hydrate. The activities of
the polychaetes, grazing on the hydrate bacteria and supplying oxygen to their habitats, appears to contribute to the dissolution
of hydrates in surface sediments.
Received: 16 August 1999 / Accepted in revised form: 19 January 2000 相似文献
20.
Photoperiod and dietary lipids both influence thermal physiology and the pattern of torpor of heterothermic mammals. The aim
of the present study was to test the hypothesis that photoperiod-induced physiological changes are linked to differences in
tissue fatty acid composition of deer mice, Peromyscus maniculatus (∼18-g body mass). Deer mice were acclimated for >8 weeks to one of three photoperiods (LD, light/dark): LD 8:16 (short photoperiod),
LD 12:12 (equinox photoperiod), and LD 16:8 (long photoperiod). Deer mice under short and equinox photoperiods showed a greater
occurrence of torpor than those under long photoperiods (71, 70, and 14%, respectively). The duration of torpor bouts was
longest in deer mice under short photoperiod (9.3 ± 2.6 h), intermediate under equinox photoperiod (5.1 ± 0.3 h), and shortest
under long photoperiod (3.7 ± 0.6 h). Physiological differences in torpor use were associated with significant alterations
of fatty acid composition in ∼50% of the major fatty acids from leg muscle total lipids, whereas white adipose tissue fatty
acid composition showed fewer changes. Our results provide the first evidence that physiological changes due to photoperiod
exposure do result in changes in lipid composition in the muscle tissue of deer mice and suggest that these may play a role
in survival of low body temperature and metabolic rate during torpor, thus, enhancing favourable energy balance over the course
of the winter. 相似文献