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1.
Comparison of hibernation, estivation and daily torpor in the edible dormouse, Glis glis 总被引:2,自引:0,他引:2
Wilz M Heldmaier G 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2000,170(7):511-521
Three major forms of dormancy in mammals have been classified: hibernation in endotherms is characterised by reduced metabolic
rate (MR) and body temperature (T
b) near ambient temperature (T
a) over prolonged times in the winter. Estivation is a similar form of dormancy in a dry and hot environment during summertime.
Daily torpor is defined as reduced MR and T
b lower than 32 °C, limited to a duration of less than 24 h. The edible dormouse (Glis glis) is capable for all three distinct forms of dormancy. During periods of food restriction and/or low T
a, daily torpor is displayed throughout the year, alternating with hibernation and estivation in winter and summer respectively.
We recorded T
b, O2-consumption and CO2-production in unrestrained dormice at different T
a's for periods of up to several months. Cooling rate and rate of metabolic depression during entrance into the torpid state
was identical in all three forms of dormancy. The same was true for thermal conductance, maximum heat production, duration
of arousal and cost of an arousal. The only difference between hibernation and daily torpor was found in the bout duration.
A daily torpor bout lasted 3–21 h, a hibernation bout 39–768 h. As a consequence of prolonged duration, MR, T
b and also the T
b − T
a gradient decreased to lower values during hibernation bouts when compared to daily torpor bouts. Our findings suggest that
all three forms of dormancy are based on the same physiological mechanism of thermal and metabolic regulation.
Accepted: 27 June 2000 相似文献
2.
Williams CT Sheriff MJ Schmutz JA Kohl F Tøien Ø Buck CL Barnes BM 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2011,181(8):1101-1109
Precise measures of phenology are critical to understanding how animals organize their annual cycles and how individuals and
populations respond to climate-induced changes in physical and ecological stressors. We show that patterns of core body temperature
(T
b) can be used to precisely determine the timing of key seasonal events including hibernation, mating and parturition, and
immergence and emergence from the hibernacula in free-living arctic ground squirrels (Urocitellus parryii). Using temperature loggers that recorded T
b every 20 min for up to 18 months, we monitored core T
b from three females that subsequently gave birth in captivity and from 66 female and 57 male ground squirrels free-living
in the northern foothills of the Brooks Range Alaska. In addition, dates of emergence from hibernation were visually confirmed
for four free-living male squirrels. Average T
b in captive females decreased by 0.5–1.0°C during gestation and abruptly increased by 1–1.5°C on the day of parturition. In
free-living females, similar shifts in T
b were observed in 78% (n = 9) of yearlings and 94% (n = 31) of adults; females without the shift are assumed not to have given birth. Three of four ground squirrels for which
dates of emergence from hibernation were visually confirmed did not exhibit obvious diurnal rhythms in T
b until they first emerged onto the surface when T
b patterns became diurnal. In free-living males undergoing reproductive maturation, this pre-emergence euthermic interval averaged
20.4 days (n = 56). T
b-loggers represent a cost-effective and logistically feasible method to precisely investigate the phenology of reproduction
and hibernation in ground squirrels. 相似文献
3.
Thomas Waßmer Franziska Wollnik 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(4):270-279
Body temperature (T
b) of seven European hamsters maintained at constant ambient temperature (T
a = 8 °C) and constant photoperiod (LD 8:16) was recorded throughout the hibernating season using intraperitoneal temperature-sensitive
HF transmitters. The animals spent about 30% of the hibernation season in hypothermia and 70% in inter-bout normothermy. Three
types of hypothermia, namely deep hibernation bouts (DHBs), short hibernation bouts (SHBs), and short and shallow hibernation
bouts (SSHBs), were distinguished by differences in bout duration and minimal body temperature (T
m). A gradual development of SSHBs from the diel minimum of T
b during normothermy could be seen in individual hamsters, suggesting a stepwise decrease of the homeostatic setpoint of T
b regulation during the early hibernation season. Entry into hibernation followed a 24-h rhythm occurring at preferred times
of the day in all three types of hypothermia. DHBs and SHBs were initiated approximately 4 h before SSHBs, indicating a general
difference in the physiological initiation of SSHBs on the one hand and DHBs and SHBs on the other. Arousals from SHBs and
SSHBs also followed a 24-h rhythm, whereas spontaneous arousals from DHBs were widely scattered across day and night. Statistical
analyses of bout length and the interval between arousals revealed evidence for a free-running circadian rhythm underlying
the timing of arousals. The results clearly demonstrate that entries into hypothermia are linked to the light/dark-cycle.
However, the role of the circadian system in the timing of arousals from DHBs remains unclear.
Accepted: 11 December 1996 相似文献
4.
The hibernating marsupial mountain pygmy-possum (Burramys parvus, 40 g) has to raise its slow-growing offspring during a short alpine summer. Only females provide parental care, while after
mating males emigrate to marginal habitats often at lower altitudes which can sustain only low possum densities. We predicted
that the hibernation strategies in mountain pygmy-possums are distinct from those of similar-sized placental hibernators,
because of the developmental constraints in marsupials and because hibernation differs between the sexes. Using temperature-sensitive
radio transmitters, we studied the hibernation patterns of free-living male and female mountain pygmy-possums living in a
north- and a south-facing boulder field (Kosciusko National Park) for two consecutive winters. Individual possums commenced
hibernation several months before the snow season. As in other hibernators, torpor in the mountain pygmy-possum was interrupted
by periodic arousals which occurred most often during the late afternoon. Torpor bouts initially lasted a few days when the
hibernacula temperature (T
hib) ranged from 4 to 7°C. As the hibernation season progressed, torpor bouts became longer and possum body temperatures (T
b) approached 2°C. The T
bs of females were significantly lower and torpor bouts were longer in the second half of the hibernation season than in males.
Between torpor bouts, both sexes were often active and left hibernacula for periods of up to 5 days. Especially during the
first months of the hibernation season, possums also frequently changed hibernacula sites probably in an attempt to select
a site with a more suitable microclimate. Emergence from hibernation was closely coupled with the disappearance of snow from
the possum habitat (September 1995, October 1996) and the limited fat stores probably dictate an opportunistic spring emergence.
However, in 1995, spring was early and males emerged significantly earlier than females. In 1996, when snow melt was delayed,
this difference vanished. Testes are regressed in males during hibernation and the time needed for testes growth and spermatogenesis
favours an earlier emergence for males which was probably achieved by their preference for the more sun exposed north-facing
boulder field. A sexual dimorphism in hibernation strategies and spring emergence therefore enables mountain pygmy-possums
to cope with their harsh alpine environment.
Received: 22 May 1997 / Accepted: 21 August 1997 相似文献
5.
Heterothermy in the southern African hedgehog, <Emphasis Type="Italic">Atelerix frontalis</Emphasis>
Hallam SL Mzilikazi N 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2011,181(3):437-445
Most research on mammalian heterothermic responses in southern Africa tends to be laboratory based and biased towards rodents
and smaller members of the Afrotheria. In this study, we continuously measured body temperature of southern African hedgehogs
(Atelerix frontalis) between April and August 2009 (−10°C < T
a < 43°C), kept under semi-captive conditions. A. frontalis showed a high propensity for torpor with animals spending up to 84% of the measurement period torpid. During this study,
A. frontalis displayed the lowest T
b min (ca 1°C) yet recorded in an Afrotropical placental heterotherm. Bout lengths of between 0.7 h (40 min) and 116.3 h (4.8 days)
were recorded. Differences in bout length were observed between lighter individuals compared with an individual exhibiting
a higher body mass at the onset of winter, with low M
b individuals exhibiting daily torpor whereas a heavier individual exhibited torpor bouts that were indicative of hibernation.
Our results suggest that heterothermic responses are an important feature in the energy balance equation of this species and
that body mass at the onset of winter may determine the patterns of heterothermy utilised in this species. 相似文献
6.
Jian-Nan Liu William H. Karasov 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2011,181(1):125-135
The subtropical Formosan leaf-nosed bats, Hipposideros terasensis (Hipposideridae), show little activity during winter. It has never been determined whether in winter they exhibit hibernation
and multi-day periods of low body temperature. The objectives of this study were to understand the winter activity pattern
of H. terasensis and to examine whether it enters hibernation during winter. We monitored the skin temperature (T
sk) of nine free-ranging H. terasensis by attaching temperature-sensitive transmitters during the winters of 2007–2008 and 2008–2009. The results showed that H. terasensis entered hibernation from late December to early March. H. terasensis, however, differs from temperate hibernating bats in several ways: (1) it is capable of hibernation at roost temperature
(T
r) and T
sk > 20°C; (2) hibernation at high T
r and T
sk does not lead to a relatively high arousal frequency; and (3) adults do not increase body mass in autumn prior to hibernation.
To test the hypothesis that H. terasensis feeds frequently during the hibernation period to compensate for the high energetic demands of hibernating in warm hibernacula,
we recorded the number and timing of bats that emerged from and entered into a hibernaculum, which contained more than 1,000
bats. From 30 December 2007 to 29 February 2008, an average of only 8.4 bats (<1%) per night (29 nights) emerged from the
hibernaculum. Adult bats lost an average of 13–14% of body mass during an approximately 70-day hibernation period. We suggest
that H. terasensis might have remarkably low torpid metabolic rates during hibernation. 相似文献
7.
Gerhard Körtner A. Daniella Rojas Fritz Geiser 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2010,180(6):869-876
Many small desert dasyurids employ torpor almost daily during winter, because cold nights and low food availability impose
high energetic costs. However, in Western Australia the arid zone extends into tropical, coastal regions, where winter temperature
conditions are far less severe. We studied the thermal biology and activity patterns of free-ranging kaluta (~27 g), a dasyurid
restricted to these tropical spinifex deserts, during the Austral winter (June–July) and in addition quantified activity patterns
in captivity. Unlike most dasyurids, wild and captive kalutas were almost exclusively diurnal and retreated into underground
burrows during the night. Despite being active during the warmer part of the day, kalutas entered torpor daily. However, torpor
patterns differed remarkably between males and females. While females spent most of the night torpid at body temperatures
(T
b) as low as 21°C, close to soil temperature, males entered multiple short and shallow bouts (T
b > 25°C) during the night. Males also maintained higher T
bs during the early morning when active, occupied larger home ranges and covered greater distances while foraging than females.
Hence, males appear to expend more energy than the similar-sized females both while foraging and during the rest phase. We
propose that physiological as well as behavioural preparations for the September mating season that culminate in a complete
male die-off might already impose energetic costs on males during winter. 相似文献
8.
Kart Gür M Refinetti R Gür H 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2009,179(2):155-164
We studied daily rhythmicity of body temperature (T
b) before and during hibernation in Anatolian ground squirrels (Spermophilus xanthoprymnus) under natural and laboratory conditions using surgically implanted temperature loggers. Under both conditions, robust daily
T
b rhythmicity with parameters comparable to those of other ground squirrel species was observed before but not during hibernation.
Euthermic animals had robust daily T
b rhythms with a mean of 37.0°C and a range of excursion of approximately 4°C. No T
b rhythm was detected during torpor bouts, either because T
b rhythmicity was absent or because the daily range of excursion was smaller than 0.2°C. The general patterns of hibernation
that we observed in Anatolian ground squirrels were similar to those previously observed by other investigators in other species
of ground squirrels. 相似文献
9.
Daily and seasonal cycles of body temperature and aspects of heterothermy in the hedgehog Erinaceus europaeus 总被引:1,自引:1,他引:0
P. A. Fowler P. A. Racey 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1990,160(3):299-307
Summary Intra-abdominal temperature-sensitive radio transmitters were used to collect more than 350 sets of body temperature (T
b
) data from 23 captive adult hedgehogs over a 3-year period. Each data set comprised measurements made every 1/2 h for 24-h periods. Between 20 and 60 such data sets were recorded every calendar month, and a total of 17400 measurements of T
b
were collected. The hedgehogs were exposed to natural environmental conditions at 57°N in NE Scotland. Hedgehogs showed seasonal changes in mean daily euthermic T
b
,with a July maximum of 35.9±0.2°C, a September minimum of 34.7±0.9°C, and a marked circadian T
b
cycle that correlates closely with photoperiod. Maximal T
b
occurred within 2 h of midnight and this pattern of nocturnal maximum and diurnal minimum T
b
was most marked between April and September. The circadian T
b
cycle was least correlated with photoperiod during winter. Hibernal T
b
during winter correlated with ambient temperature (T
a
),it was maximal in September (17.7±1.0°C) and minimal in December (5.2±0.9°C). Apart from the tracking of T
a
and T
b
during hibernal bouts, with a time-lag of 4–6 h, circadian rhythmicity of hibernal T
b
was not evident. However, the T
b
of hibernating hedgehogs rose significantly when T
a
fell below — 5°C, although the animals did not neccessarily arouse. Although hibernal bouts occurred between September and April, 89.5% of such bouts were recorded between November and February. The mean time of entry into hibernation was 01:45±5.1 h GMT while the mean time of the start of spontaneous arousal from hibernation was 11:53±4.8 h GMT. Therefore, during hibernation hedgehogs were either fully aroused at night, when euthermic hedgehogs have maximalT
b
,or in deep hibernation around midday, when euthermic hedgehogs have minimal T
b
.Since wild hedgehogs will feed during spontaneous arousal from hibernation, these timings are probably adaptive, and suggest that entry into, and arousal from, hibernation may be extensions of circadian cyclicity. Spontaneous bouts of transient shallow torpor (TST) were recorded throughout the year, with nearly 80% of observations occurring during August and September, at the start of the hibernal period. TST bouts lasted for 4.9±2.9 h, with T
b
falling to 25.8±3.1 °C. Only 20% of TST bouts immediately preceded hibernation and their duration did not correlate with T
a
or body mass. TST bouts started at 06:51±4.7 h GMT, significantly later than entry into hibernation, and ended at 13:04±5.4 h GMT. The function of TST bouts is unclear, but they may be preparation for the hibernation season or a further energy conservation strategy. When arousing from hibernation hedgehogs warmed at a rate of 1.9±0.4°C·h-1, and when entering hibernation cooled at 7.9±1.9°C·h-1. Warming rates were slightly higher during mid-winter when T
b
and body mass were minimal, but cooling rates were 44% higher at the end of the hibernal period compared to the start. Cooling and warming rates were strikingly similar to those measured in hedgehogs at 31°N. These results demonstrate that thermoregulation in the hedgehog is closely regulated and changes on a seasonal basis, in meeting with requirements of surviving food shortages and low temperature during winter.Abbreviations
T
a
ambient temperature
-
T
b
body temperature
-
CSD
circular standard deviation
-
SWS
slow wave sleep
-
TST
transient shallow torpor 相似文献
10.
Wendy A. Wilson M. Justin O’Riain Robyn S. Hetem Andrea Fuller Linda G. Fick 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2010,180(7):1099-1110
The body temperature (T
b) of Cape ground squirrels (Xerus inauris, Sciuridae) living in their natural environment during winter has not yet been investigated. In this study we measured abdominal
T
b of eight free-ranging Cape ground squirrels over 27 consecutive days during the austral winter. Mean daily T
b was relatively stable at 37.0 ± 0.2°C (range 33.4 to 40.2°C) despite a marked variation in globe temperature (T
g) (range −7 to 37°C). Lactating females (n = 2) consistently had a significantly higher mean T
b (0.7°C) than non-lactating females (n = 3) and males. There was a pronounced nychthemeral rhythm with a mean active phase T
b of 38.1 ± 0.1°C and a mean inactive phase T
b of 36.3 ± 0.3°C for non-lactating individuals. Mean daily amplitude of T
b rhythm was 3.8 ± 0.2°C. T
b during the active phase closely followed T
g and mean active phase T
b was significantly correlated with mean active phase T
g (r
2 = 0.3–0.9; P < 0.01). There was no evidence for daily torpor or pronounced hypothermia during the inactive phase, and mean minimum inactive
phase T
b was 35.7 ± 0.3°C for non-lactating individuals. Several alternatives (including nocturnal huddling, an aseasonal breeding
pattern and abundant winter food resources) as to why Cape ground squirrels do not employ nocturnal hypothermia are discussed. 相似文献
11.
Mariska Batavia George Nguyen Kristine Harman Irving Zucker 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2013,183(2):269-277
Turkish hamsters (Mesocricetus brandti) are a model organism for studies of hibernation, yet a detailed account of their torpor characteristics has not been undertaken. This study employed continuous telemetric monitoring of body temperature (T b) in hibernating male and female Turkish hamsters at ambient temperatures (T as) of 5 and 13 °C to precisely characterize torpor bout depth, duration, and frequency, as well as rates of entry into and arousal from torpor. Hamsters generated brief intervals of short (<12 h), shallow test bouts (T b > 20 °C), followed by deep torpor bouts lasting 4–6 days at T a = 5 °C and 2–3 days at T a = 13 °C. Females at T a = 5 °C had longer bouts than males, but maintained higher torpor T b; there were no sex differences at T a = 13 °C. Neither body mass loss nor food intake differed between the two T as. Hamsters entered torpor primarily during the scotophase (subjective night), but timing of arousals was highly variable. Hamsters at both T as generated short, shallow torpor bouts between deep bouts, suggesting that this species may be capable of both hibernation and daily torpor. 相似文献
12.
R. Oelkrug G. Heldmaier C. W. Meyer 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2011,181(1):137-145
In eutherian mammals, uncoupling protein 1 (UCP1) mediated non-shivering thermogenesis from brown adipose tissue (BAT) provides
a mechanism through which arousal from torpor and hibernation is facilitated. In order to directly assess the magnitude by
which the presence or absence of UCP1 affects torpor patterns, rewarming and arousal rates within one species we compared
fasting induced torpor in wildtype (UCP1+/+) and UCP1-ablated mice (UCP−/−). Torpor was induced by depriving mice of food for up to 48 h and by a reduction of ambient temperature (T
a) from 30 to 18°C at four different time points after 18, 24, 30 and 36 h of food deprivation. In most cases, torpor bouts
occurred within 20 min after the switch in ambient temperature (30–18°C). Torpor bouts expressed during the light phase lasted
3–6 h while significantly longer bouts (up to 16 h) were observed when mice entered torpor during the dark phase. The degree
of hypometabolism (5–22 ml h−1) and hypothermia (19.5–26.7°C) was comparable in wildtype and UCP1-ablated mice, and both genotypes were able to regain normothermia.
In contrast to wildtype mice, UCP1-ablated mice did not display multiple torpor bouts per day and their peak rewarming rates
from torpor were reduced by 50% (UCP1+/+: 0.24 ± 0.08°C min−1; UCP1−/−: 0.12 ± 0.04°C min−1). UCP1-ablated mice therefore took significantly longer to rewarm from 25 to 32°C (39 vs. 70 min) and required 60% more energy
for this process. Our results demonstrate the energetic benefit of functional BAT for rapid arousal from torpor. They also
suggest that torpor entry and maintenance may be dependent on endogenous rhythms. 相似文献
13.
Careau V Réale D Garant D Speakman JR Humphries MM 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2012,182(3):403-414
In response to handling or other acute stressors, most mammals, including humans, experience a temporary rise in body temperature
(T
b). Although this stress-induced rise in T
b has been extensively studied on model organisms under controlled environments, individual variation in this interesting phenomenon
has not been examined in the field. We investigated the stress-induced rise in T
b in free-ranging eastern chipmunks (Tamias striatus) to determine first if it is repeatable. We predicted that the stress-induced rise in T
b should be positively correlated to factors affecting heat production and heat dissipation, including ambient temperature
(T
a), body mass (M
b), and field metabolic rate (FMR). Over two summers, we recorded both T
b within the first minute of handling time (T
b1) and after 5 min of handling time (T
b5) 294 times on 140 individuals. The mean ∆T
b (T
b5 – T
b1) during this short interval was 0.30 ± 0.02°C, confirming that the stress-induced rise in T
b occurs in chipmunks. Consistent differences among individuals accounted for 40% of the total variation in ∆T
b (i.e. the stress-induced rise in T
b is significantly repeatable). We also found that the stress-induced rise in T
b was positively correlated to T
a, M
b, and mass-adjusted FMR. These results confirm that individuals consistently differ in their expression of the stress-induced
rise in T
b and that the extent of its expression is affected by factors related to heat production and dissipation. We highlight some
research constraints and opportunities related to the integration of this laboratory paradigm into physiological and evolutionary
ecology. 相似文献
14.
Post‐hibernated bumblebee (Bombus terrestris) queens were kept for 1 week under photoperiodic conditions of 8 h light : 16 h dark, and at four different temperatures (24, 28, 32 and 36°C). The reproductive performance of the queens was then observed. It was found that exposure temperature and hibernation duration did not affect the oviposition rate. The pre‐oviposition period was found to be shortest (3.8 ± 0.7 days) for queens that had hibernated for 4.0 months and had been activated at 28°C. Timing of the initiation of the switch‐point was not affected by exposure temperature and hibernation duration. Significantly higher numbers of workers (268.0 ± 31.4) and sexual queens (119.3 ± 16.8) were produced by the queens that had hibernated for 3.0 months and had been activated at 28 and 36°C, respectively. The queens that had hibernated for 4.0 months and had been activated at 36°C produced the highest number of males (296.2 ± 32.3). 相似文献
15.
W. Bartels B. S. Law F. Geiser 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1998,168(3):233-239
Little is known about torpor in the tropics or torpor in megachiropteran species. We investigated thermoregulation, energetics
and patterns of torpor in the northern blossom-bat Macroglossus minimus (16 g) to test whether physiological variables may explain why its range is limited to tropical regions. Normothermic bats
showed a large variation in body temperature (T
b) (33 to 37 °C) over a wide range of ambient temperatures (T
as) and a relatively low basal metabolic rate (1.29 ml O2 g−1 h−1). Bats entered torpor frequently in the laboratory at T
as between 14 and 25 °C. Entry into torpor always occurred when lights were switched on in the morning, independent of T
a. MRs during torpor were reduced to about 20–40% of normothermic bats and T
bs were regulated at a minimum of 23.1 ± 1.4 °C. The duration of torpor bouts increased with decreasing T
a in non-thermoregulating bats, but generally terminated after 8 h in thermoregulating torpid bats. Both the mean minimum T
b and MR of torpid M. minimus were higher than that predicted for a 16-g daily heterotherm and the T
b was also about 5 °C higher than that of the common blossom-bat Syconycteris australis, which has a more subtropical distribution. These observations suggest that variables associated with torpor are affected
by T
a and that the restriction to tropical areas in M. minimus to some extent may be due to their ability to enter only very shallow daily torpor.
Accepted: 22 September 1997 相似文献
16.
Yi-Guang Chen Jun Chen Qi-Hui Chen Shu-Kun Tang Yu-Qin Zhang Jian-Wu He Wen-Jun Li Yan-Qi Liu 《Antonie van Leeuwenhoek》2010,98(3):395-401
A novel Gram-stain-positive, slightly halophilic, facultatively alkaliphilic, non-motile, non-sporulating, catalase-positive,
oxidase-negative, aerobic bacterium, designated strain JSM 070026T, was isolated from non-saline forest soil in China. Growth occurred with 0–20% (w/v) NaCl (optimum, 2–4%) and at pH 6.0–10.5
(optimum, pH 8.0) and 5–40°C (optimum, 30°C). Good growth also occurred in the presence of 0–28% (w/v) KCl (optimum, 2–5%)
or 0–25% (w/v) MgCl2·6H2O (optimum, 1–4%). The peptidoglycan type was A4α (l-Lys–Gly–l-Glu). Cell-wall sugars contained mannose and xylose. The major cellular fatty acids were anteiso-C15:0 and iso-C15:0. Strain
JSM 070026T contained menaquinone 8 as the major respiratory quinone and diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol
as the major polar lipids. The DNA G + C content of strain JSM 070026T was 56.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain JSM 070026T was a member of the suborder Micrococcineae and most closely related to Yaniella flava YIM 70178T (sequence similarity 99.4%) and Yaniella halotolerans YIM 70085T (97.9%). The three strains formed a distinct branch in the phylogenetic tree. The combination of phylogenetic analysis, DNA–DNA
relatedness values, phenotypic characteristics and chemotaxonomic data supports the proposal that strain JSM 070026T represents a novel species of the genus Yaniella, for which the name Yaniella soli sp. nov. is proposed. The type strain is JSM 070026T (=DSM 22211T = KCTC 13527T). 相似文献
17.
Huang HY Chen YG Wang YX Liu JH Tang SK Peng Q Wen ML Yu H Cui XL 《Extremophiles : life under extreme conditions》2008,12(6):829-835
A novel Gram-negative, slightly halophilic, catalase- and oxidase-positive, obligately aerobic bacterium, strain YIM-C248T, was isolated from a sediment sample collected from a salt-lake in the Qaidam Basin in Qinghai, north-west China. Cells were
non-sporulating short rods, occurring singly or as doublets, motile with peritrichous flagella. Growth occurred with 1–15%
(w/v) NaCl [optimum 2–4% (w/v) NaCl], at pH 6.0–10.0 (optimum pH 7.5) and at 4–35°C (optimum 25–30°C). The major cellular
fatty acids were C18:1
ω7c, C12:0 3-OH, cyclo C19:0
ω8c, C16:0 and C16:1. The predominant respiratory quinone was Q-9 and the genomic DNA G + C content was 58.6 mol%. Phylogenetic analysis based
on 16S rRNA gene sequences indicated that strain YIM-C248T should be assigned to the genus Halomonas. The sequence similarities between the isolate and the type strains of members of the genus Halomonas were in the range of 92.5–97.5%. The combination of phylogenetic analysis, DNA–DNA hybridization data, phenotypic characteristics
and chemotaxonomic differences supported the view that strain YIM-C248T represents a new species of the genus Halomonas, for which the name Halomonas sediminis sp. nov. is proposed, with YIM-C248T (=CCTCC AA 207031 = KCTC 22167) as the type strain.
The GenBank/EMBL/DBBJ accession number for the 16S rRNA gene sequence of strain YIM-C248T is EU135707. 相似文献
18.
19.
Daily torpor in the gray mouse lemur (Microcebus murinus) in Madagascar: energetic consequences and biological significance 总被引:5,自引:0,他引:5
J. Schmid 《Oecologia》2000,123(2):175-183
Patterns and energetic consequences of spontaneous daily torpor were measured in the gray mouse lemur (Microcebus murinus) under natural conditions of ambient temperature and photoperiod in a dry deciduous forest in western Madagascar. Over a
period of two consecutive dry seasons, oxygen consumption (VO2) and body temperature (T
b) were measured on ten individuals kept in outdoor enclosures. In all animals, spontaneous daily torpor occurred on a daily
basis with torpor bouts lasting from 3.6 to 17.6 h, with a mean torpor bout duration of 9.3 h. On average, body temperatures
in torpor were 17.3±4.9°C with a recorded minimum value of 7.8°C. Torpor was not restricted to the mouse lemurs’ diurnal resting
phase: entries occurred throughout the night and arousals mainly around midday, coinciding with the daily ambient temperature
maximum. Arousal from torpor was a two-phase process with a first passive, exogenous heating where the T
b of animals increased from the torpor T
b minimum to a mean value of 27.1°C before the second, endogenous heat production commenced to further raise T
b to normothermic values. Metabolic rate during torpor (28.6±13.2 ml O2 h–1) was significantly reduced by about 76% compared to resting metabolic rate (132.6±50.5 ml O2 h–1). On average, for all M. murinus individuals measured, hypometabolism during daily torpor reduced daily energy expenditure by about 38%. In conclusion, all
these energy-conserving mechanisms of the nocturnal mouse lemurs, with passive exogenous heating during arousal from torpor,
low minimum torpor T
bs, and extended torpor bouts into the activity phase, comprise an important and highly adapted mechanism to minimize energetic
costs in response to unfavorable environmental conditions and may play a crucial role for individual fitness.
Received: 8 July 1999 / Accepted: 3 December 1999 相似文献
20.
Yi-Guang Chen Huai-Dong Xiao Shu-Kun Tang Yu-Qin Zhang Entomack Borrathybay Xiao-Long Cui Wen-Jun Li Yan-Qi Liu 《Antonie van Leeuwenhoek》2009,96(3):259-266
A pale yellow-colored, moderately halophilic, Gram-negative, catalase- and oxidase-positive, non-sporulating, rod-shaped,
motile, aerobic bacterium, designated strain JSM 073008T, was isolated from a sea anemone (Anthopleura xanthogrammica) collected from Naozhou Island, Leizhou Bay, South China Sea. The organism was able to grow with 1–20% (w/v) total salts
(optimum, 5–10%), at pH 6.0–10.0 (optimum, pH 7.5) and 10–40°C (optimum, 25–30°C). The major cellular fatty acids were C16:0, C16:1
ω7c/iso-C15:0 2-OH and C18:1
ω7c. The polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol and an unidentified phospholipid. The predominant
respiratory quinone was Q-8 and the genomic DNA G + C content was 47.5 mol%. Phylogenetic analysis based on 16S rRNA gene
sequences indicated that strain JSM 073008T should be assigned to the genus Alteromonas, being most closely related to Alteromonas hispanica F-32T (sequence similarity 96.9%), followed by Alteromonas genovensis LMG 24078T (96.6%) and Alteromonas litorea TF-22T (96.4%). The sequence similarities between the novel isolate and the type strains of other recognized Alteromonas species ranged from 95.9% (with Alteromonas stellipolaris ANT 69aT) to 94.5% (with Alteromonas simiduii BCRC 17572T). The combination of phylogenetic analysis, phenotypic characteristics and chemotaxonomic data supported the view that strain
JSM 073008T represents a new species of the genus Alteromonas, for which the name Alteromonas halophila sp. nov. is proposed. The type strain is JSM 073008T (=CCTCC AA 207035T = KCTC 22164T).
The authors Yi-Guang Chen and Huai-Dong Xiao have contributed equally to this work. 相似文献