共查询到20条相似文献,搜索用时 31 毫秒
1.
Microrheological properties (aggregation and deformability) of erythrocytes separated by centrifugation at 30000×g density gradient into “young” and “old” (the upper and lower fractions, respectively) were studied. The erythrocytes were
taken from physically active persons (PAP) and from those with elevated arterial pressure (EAP). A significant difference
in microrheological properties of the “young” and “old” erythrocytes was found. The aggregation degree of “old” cells was
nearly twice that of “young” cells. The deformability of the erythrocyte subpopulations was significantly different, though
the difference was not so pronounced as in the case of aggregation. The aggregation of “young” and “old” erythrocytes in the
PAP group was the least (28% lower than in the control). Note, that “old” erythrocytes in the PAP group had better microrheological
properties than in the other groups. All erythrocyte populations in the EAP group were characterized by higher aggregation,
decreased deformability, and decreased capacity for oxygen transport. 相似文献
2.
Hanna Ciecierska 《Hydrobiologia》2006,570(1):141-146
Urban lakes belong to various groups, for example from “young” to “old” with regard to development, and from “natural” to
“anthropogenic” with respect to transformations due to human activity. The majority of these lakes are eutrophic and polytrophic,
but special attention should be paid to mesotrophic ones, with relatively unchanged vegetation, with species of the class
Charetea, e.g. Lake Redykajny (43.3% of the phytolittoral) or Lake Tyrsko (44.0% of the phytolittoral). 相似文献
3.
We report the first study of the relation between the wavelength of maximum absorbance (λmax) and the photoactivation energy (E
a) in invertebrate visual pigments. Two populations of the opossum shrimp Mysis relicta were compared. The two have been separated for 9,000 years and have adapted to different spectral environments (“Sea” and
“Lake”) with porphyropsins peaking at λmax=529 nm and 554 nm, respectively. The estimation of E
a was based on measurement of temperature effects on the spectral sensitivity of the eye. In accordance with theory (Stiles
in Transactions of the optical convention of the worshipful company of spectacle makers. Spectacle Makers’ Co., London, 1948), relative sensitivity to long wavelengths increased with rising temperature. The estimates calculated from this effect are
E
a,529=47.8±1.8 kcal/mol and E
a,554=41.5±0.7 kcal/mol (different at P<0.01). Thus the red-shift of λmax in the “Lake” population, correlating with the long-wavelength dominated light environment, is achieved by changes in the
opsin that decrease the energy gap between the ground state and the first excited state of the chromophore. We propose that
this will carry a cost in terms of increased thermal noise, and that evolutionary adaptation of the visual pigment to the
light environment is directed towards maximizing the signal-to-noise ratio rather than the quantum catch. 相似文献
4.
J. Terraube B. E. Arroyo F. Mougeot T. E. Katzner E. A. Bragin 《Journal of Ornithology》2010,151(3):713-722
The ecology and conservation status of Central Asian populations of Montagu’s Harriers Circus pygargus are poorly known. We studied the breeding biology of this species during 3 years in the Naurzum region, north-central Kazakhstan.
Most Montagu’s Harriers in the study area nested in the forest-steppe transition area, in bushy areas dominated by dogrose
Rosa canina, which was apparently the nesting vegetation type providing highest and densest nest cover in the study area. Laying occurred
from 26 April to 7 June (average 13 May, n = 49) and, although it varied significantly between years, was earlier than in western European populations of similar latitude.
Mean (±SD) clutch size was 4.44 ± 0.86 (range 2–6; n = 50), in the higher range observed for the species. There was no significant interannual variation in clutch size, despite
large variations in the abundance of small mammals in the area. Diet was mainly composed of lizards (54.2%, n = 533 identified prey in all 3 years), with small mammals (17.1%), passerine birds (14.3%) and insects (13.6%) also being
consumed. Mean brood size at the last visit was 2.55 ± 2.10 (range 0–6; n = 51). Failure rate was relatively high; the main identified cause of nest failure was predation. We compare the data obtained
in this population breeding in natural steppes with breeding parameters from the well-studied western European populations,
and discuss the implications for the conservation of this species. 相似文献
5.
The reproductive value hypothesis predicts that the level of nest defence is determined by the expected chance of offspring
to survive until reproduction, and by the reproductive potential of the parents. Rates of survival from one breeding season
to the next are low in small passerines, and their residual reproductive potential strongly declines as the current breeding
season terminates. Therefore, we can expect that parents which have only one breeding attempt per season should defend their
nests more intensively than parents with a possibility to renest. We studied nest defence in populations of meadow pipit (Anthus pratensis) breeding in Norway and the Czech Republic, differing in renesting potential. To simulate the threat from a predator, we
placed a stuffed stoat (Mustela erminea) first 5 m and then 1 m away from a nest with nestlings. Parents increased or kept nest defence constant when the stoat approached
their nests in Norway and, during a breeding season shortened by severe weather, in the Czech Republic (when renesting potential
was limited). Parents decreased nest defence when the stoat approached the nest during “normal” breeding seasons in the Czech
Republic (when renesting was common). These findings give support to the reproductive value hypothesis. 相似文献
6.
Edith Falcón-Ramírez Leonora Casas-Avila Antonio Miranda Pilar Diez Clementina Castro Julieta Rubio Rocío Gómez Margarita Valdés-Flores 《Molecular biology reports》2011,38(5):2987-2992
The Sp1 binding site polymorphism in collagen type I alpha 1 gene (COLIA1) has been associated with osteoporosis (OP) and
bone mineral density (BMD). The aim of this study was to explore the association of this polymorphism with OP and BMD in the
Mexican population by polymerase chain reaction and restriction fragment length polymorphism (PCR–RFLP) procedure. Allelic
and genotypic frequencies from the Sp1 polymorphism were determined in 100 women with OP, 100 women without OP and 500 subjects
from general Mexican population (GMP). Distribution of Sp1 polymorphism was in Hardy–Weinberg equilibrium. In spite of population
structure due to racial mix in Mexican population, associations with OP were demonstrated. The frequency of “s” allele was
significantly higher in women with OP (35%) than in women without OP (11%; P < 0.00001). Interestingly, “ss” genotype, was exclusive of women with OP and was associated with low BMD (0.588 ± 0.077 g/cm2) in contrast to “SS” genotype (0.733 ± 0.039 g/cm2; P = 0.0001). This work confirms the association of Sp1 polymorphism with low BMD and OP in Mexican population and make sure
to use Sp1 as a genetic marker for OP in our population. 相似文献
7.
Nest‐site characteristics,breeding success and competitive interactions between two recently sympatric apex predators
下载免费PDF全文
![点击此处可从《Ibis》网站下载免费的PDF全文](/ch/ext_images/free.gif)
An influential period in avian life‐cycles is the annual breeding season, when competition over suitable nesting sites and territories is a key factor that can determine fitness and distribution, especially for species that are highly selective in their nesting habitats. We analysed nest‐site characteristics, breeding success and competitive interactions between two apex predator populations. Whereas the Short‐toed Eagle Circaetus gallicus has nested in the Judean Foothills (Israel) for a long time, the Long‐legged Buzzard Buteo rufinus has only invaded the nesting habitat of the Short‐toed Eagle during their breeding season in the last two decades. These two recently sympatric species have similar nesting ecology and frequently use the same nests. They are therefore expected to compete over nesting sites and territories. We analysed interspecific interactions between these two species by combining information from comprehensive observational, experimental, GIS analysis and remote sensing data, deriving 65 variables to characterize the nest‐sites used and the breeding success in 381 breeding attempts over four consecutive breeding seasons. To assess interspecific and intraspecific territorial behaviour and aggressiveness, stuffed Long‐legged Buzzards and Short‐toed Eagles were presented close to nests. Nest‐site characteristics overlapped substantially between species, and Long‐legged Buzzards occupied 21% of all Short‐toed Eagle nests. Intraspecific aggression rates among Long‐legged Buzzards were higher than their interspecific aggression rates with Short‐toed Eagles and also higher than intraspecific aggression among Short‐toed Eagles. Long‐legged Buzzard and Short‐toed Eagle breeding densities (1.59 ± 0.11 and 2.96 ± 0.11 pairs per 10 km2, respectively) are likely to be the highest across their respective breeding distributions, with a maximum productivity of 0.96 ± 0.01 and 0.56 ± 0.05 (young fledged/breeding pair) for Long‐legged Buzzard and Short‐toed Eagle, respectively. Intraspecific interactions among both species play an important role in determining their breeding success and the spatial distribution of nesting sites. Our results suggest that interspecific competition over nesting sites and territories between both species, and the potential dominance of Long‐legged Buzzard, has both direct and indirect impacts on the spatial and demographic distribution of Short‐toed Eagles due to the recent establishment of Long‐legged Buzzard territories in the Judean breeding area. 相似文献
8.
The small ant Camponotus anderseni lives exclusively in twigs of the mangrove tree Sonneratia alba, and during inundation, the entrance hole is blocked with a soldier’s head which effectively prevents flooding. The nests
can be very crowded, with the ants and coccids filling up to 50% of the volume, and due to their metabolic activity, the conditions
in the nests during inundation become hypercapnic and hypoxic.
Each nest has only one entrance, and the opening is quite small (1.56 ± 0.03 mm). The mean diameter of the galleries is 2.31
± 0.23 mm, independent of the thickness of the twig and length of the nest. During normal conditions with open nests, the
oxygen depletion is substantial in the part of the nest most distant from the opening, and in a 120 mm long nest the oxygen
concentration can be as low as 15.7%. During simulated inundation, in which the nest entrances were blocked, the oxygen concentration
dropped to very low levels (<0.5%) after one hour. After opening the nest entrance, the oxygen concentration increased again,
but for a 100 mm long nest it took nearly 20 minutes before the concentration was back to the normal depressed level.
Mathematical modelling of the steady-state oxygen concentrations in the innermost part of the nests shows a lower O2 concentration than calculated. The time for equilibration of oxygen after inundation is longer than expected for small nests,
presumably because the passive diffusion is obstructed by the nest contents. The “dilemma” faced by C. anderseni is to avoid drowning without suffering anoxia or hypercapnia, and they show a remarkable ability to adapt to the extreme
conditions in the mangrove and exploit a niche where the density of other ants is insignificant.
Received 13 December 2007; revised 30 July 2008; accepted 6 September 2008. 相似文献
9.
To relate the pharmacokinetics of orally administered lansoprazole in healthy adult Jordanian men with CYP2C19 polymorphisms
and to determine the percentage of CYP2C19 polymorphism in Jordanian population and the allelic frequency of CYP2C19*2 and CYP2C19*3. A total of 78 healthy Jordanian volunteers were included in this study from three different bioequivalence studies, one
of these studies which included 26 volunteers was done on lansoprazole. Genotyping for CYP2C19*1, CYP2C19*2, CYP2C19*3 was done for all 78 volunteers, the data of genotyping of all subjects used for screening the frequency of different genotypes
and the allelic frequency of different polymorphisms in healthy Jordanian men, the pharmacokinetics and genotyping data for
the study of lansoprazole was matched and compared to investigate presence of statistical differences in pharmacokinetic parameters.
In Jordanian subjects, the allele frequencies of the CYP2C19*2 and CYP2C19*3 mutation were 0.16 and 0, respectively. The concentration–time curves in the two groups [homozygote extensive metabolizer
(homEM, n = 19) and heterozygote extensive metabolizer (homEM, n = 7)] groups were fitted to a non-compartment model. In the homEM and in the hetEM groups, the main kinetic parameters were
as follows: Tmax (2.1875 ± 0.777) and (2.54 ± 1.87) h, Cmax (697.875 ± 335) and (833.58 ± 436.26) mg/l, t1/2 (1.3 ± 0.43) and (2.38 ± 1.64) h, AUC(0→∞) were (1,684.9 ± 888) and (3,609.8 ± 318) mg h l−1, respectively. The Jordanian population showed similarities in CYP2C19 allele and genotype distribution pattern with Caucasians and Africans. CYP2C19 allele and poor metabolizer (PM) genotype frequencies in the Jordanian population are distinct from populations’ from East
Asia such as Japanese and Koreans. Although lower pharmacokinetic parameters were found in homEM compared to hetEM but there
was no significant difference between the two groups (P < 0.05). 相似文献
10.
G. M. Artmann Ilya Digel K. F. Zerlin Ch. Maggakis-Kelemen Pt. Linder D. Porst P. Kayser A. M. Stadler G. Dikta A. Temiz Artmann 《European biophysics journal : EBJ》2009,38(5):589-600
When aspirating human red blood cells (RBCs) into 1.3 μm pipettes (ΔP = −2.3 kPa), a transition from blocking the pipette below a critical temperature T
c = 36.3 ± 0.3°C to passing it above the T
c occurred (micropipette passage transition). With a 1.1 μm pipette no passage was seen which enabled RBC volume measurements
also above T
c. With increasing temperature RBCs lost volume significantly faster below than above a T
c = 36.4 ± 0.7 (volume transition). Colloid osmotic pressure (COP) measurements of RBCs in autologous plasma (25°C ≤ T ≤ 39.5°C) showed a T
c at 37.1 ± 0.2°C above which the COP rapidly decreased (COP transition). In NMR T1-relaxation time measurements, the T1 of RBCs in autologous plasma changed from a linear (r = 0.99) increment below T
c = 37 ± 1°C at a rate of 0.023 s/K into zero slope above T
c (RBC T1 transition). In conclusion: An amorphous hemoglobin–water gel formed in the spherical trail, the residual partial sphere
of the aspirated RBC. At T
c, a sudden fluidization of the gel occurs. All changes mentioned above happen at a distinct T
c close to body temperature. The T
c is moved +0.8°C to higher temperatures when a D2O buffer is used. We suggest a mechanism similar to a “glass transition” or a “colloidal phase transition”. At T
c, the stabilizing Hb bound water molecules reach a threshold number enabling a partial Hb unfolding. Thus, Hb senses body
temperature which must be inscribed in the primary structure of hemoglobin and possibly other proteins.
This article is dedicated to Ludwig Artmann who died on July 21, 2001 on a beautiful summer day during which we performed
experiments far away. Ludwig Artmann was a man who encouraged us to be strong and to study hard no matter what were the costs. 相似文献
11.
I?igo Zuberogoitia Jose Antonio Martínez Ainara Azkona Jose Enrique Martínez I?aki Castillo Jabi Zabala 《Journal of Ornithology》2009,150(1):95-101
Methods of evaluating population trends have recently received particular attention because of perceived declines in several
species during the twentieth century. We have studied demographic traits of the peregrine falcon (Falco peregrinus) population in Bizkaia (Northern Spain) for 11 years. This species suffered a severe decline in the 1950s and 1960s and started
to recover in the 1980s and 1990s, although the recovery trends differed between areas. In our study area the peregrine falcon
density is one of the highest found in Spain. The frequency of juvenile breeders was 2.0%, the mean age at first breeding
being 3.7 calendar years for males and 4.0 cy for females. The territorial fidelity was at least 3.4 years for males and 3.7 years
for females. Females dispersed on average 80.5 km and males 51.8 km during their pre-breeding movements, whilst distance between
birthplace and breeding territories was on average 108.5 km for females and 64.5 km for males. We studied the relationships
between adult turnover, recruitment age, territorial fidelity and dispersal in a healthy population in order to establish
population dynamics. A combination of these parameters, not just age at first breeding, could be used as a potential early
warning signal indicating future changes, prompting their consequences to be evaluated. This approach could lead to the reclassification
of the large-scale health of a population. Its utilization would allow resources to be directed into helping “ailing” subpopulations,
detecting causes of decline, and developing adequate recovery strategies. 相似文献
12.
Virgínia?Carla?A.?Falc?o Mario?Augusto?Ono Tatiana?de?ávila Miguel Edio?Vizoni Elisa?Yoko?Hirooka Elisabete?Yurie?Sataque?Ono
The objectives of this study were to evaluate the fumonisin production by 16 F. verticillioides strains on corn cultures and the effect of quintozene and fludioxonil + metalaxyl-M fungicides on “in vitro” mycelial growth
on agar. In addition, the effect of fludioxonil + metalaxyl-M on fumonisin production in defined liquid culture medium was
analyzed. Fumonisin B1 levels on corn cultures ranged from 2.41 to 3996.36 μg/g and the F. verticillioides 103F strain produced the highest level (3996.36 ± 390.49 μg/g, P < 0.05). F. verticillioides strains were inoculated in potato dextrose agar with the addition of quintozene (75 to 9,375 μg/ml) and fludioxonil + metalaxyl-M
(1.5 + 0.6 to 187.5 + 75 μg/ml) in order to evaluate the effect of these fungicides on “in vitro” mycelial growth. The F. verticillioides strains showed great variability concerning ED50 values, which were below the recommended application dose for quintozene, but above that for fludioxonil + metalaxyl-M. Moreover,
fungicide addition to the culture medium increased mean FB1 levels compared to the control, suggesting the importance of focusing on the effect of fungicides on mycotoxin production
as well as on the phytopathogen control. 相似文献
13.
Assessing the importance of artificial nest‐sites in the population dynamics of endangered Northern Aplomado Falcons Falco femoralis septentrionalis in South Texas using stochastic simulation models
下载免费PDF全文
![点击此处可从《Ibis》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Habitat availability might be the most important determinant of success for a species reintroduction programme, making investigation of the quality and quantity of habitat needed to produce self‐sustaining populations a research priority for reintroduction ecologists. We used a stochastic model of population dynamics to predict whether attempts to improve existing breeding territories using artificial nest platforms improved the population growth rate and persistence of a reintroduced population of Northern Aplomado Falcons Falco femoralis septentrionalis in South Texas. We further assessed whether the creation of new territories, i.e. conversion of entire areas to suitable habitat and not simply the erection of nest platforms, would lead to a subsequent increase in the nesting population. Our model was able to reproduce several characteristics of the wild population and predicted the number of breeding pairs per year strikingly well (R2 = 0.97). Simulations revealed that the addition of nest platforms improved productivity such that the population would decline to extinction without them but is stable since their installation. Moreover, the model predicted that the increase in productivity due to nest platforms would cause the population to saturate available breeding territories, at which point the population would contain a moderate proportion of non‐territorial birds that could occupy territories if new ones become available. Population size would therefore be proportional to the increase in available territories. Our study demonstrates that artificial nest‐sites can be an effective tool for the management of reintroduced species. 相似文献
14.
The use of stored nutrients for reproduction represents an important component of life-history variation. Recent studies from
several species have used stable isotopes to estimate the reliance on stored body reserves in reproduction. Such approaches
rely on population-level dietary endpoints to characterize stored reserves (“capital”) and current diet (“income”). Individual
variation in diet choice has so far not been incorporated in such approaches, but is crucial for assessing variation in nutrient
allocation strategies. We investigated nutrient allocation to egg production in a large-bodied sea duck in northern Alaska,
the king eider (Somateria spectabilis). We first used Bayesian isotopic mixing models to quantify at the population level the amount of endogenous carbon and nitrogen
invested into egg proteins based on carbon and nitrogen isotope ratios. We then defined the isotopic signature of the current
diet of every nesting female based on isotope ratios of eggshell membranes, because diets varied isotopically among individual
king eiders on breeding grounds. We used these individual-based dietary isotope signals to characterize nutrient allocation
for each female in the study population. At the population level, the Bayesian and the individual-based approaches yielded
identical results, and showed that king eiders used an income strategy for the synthesis of egg proteins. The majority of
the carbon and nitrogen in albumen (C: 86 ± 18%, N: 99 ± 1%) and the nitrogen in lipid-free yolk (90 ± 15%) were derived from
food consumed on breeding grounds. Carbon in lipid-free yolk derived evenly from endogenous sources and current diet (exogenous
C: 54 ± 24%), but source contribution was highly variable among individual females. These results suggest that even large-bodied
birds traditionally viewed as capital breeders use exogenous nutrients for reproduction. We recommend that investigations
of nutrient allocation should incorporate individual variation into mixing models to reveal intraspecific variation in reproductive
strategies. 相似文献
15.
Mario C. N. Saparrat Geraldine E. Fermoselle Sebastián A. Stenglein Mónica B. Aulicino Pedro A. Balatti 《Mycopathologia》2009,168(1):41-47
Pseudocercospora griseola is the causal agent of angular leaf spot of common bean (ALS). It has undergone parallel coevolution with its host and two
major groups have been defined, “Andean” (P. griseola f. griseola) and “Mesoamerican” (P. griseola f. mesoamericana). The aim of this study was to analyze the nature and the level of the dark pigment synthesized by the representatives of
each group. After 21 days of incubation on potato dextrose agar medium, P. griseola f. griseola isolate S3b developed colonies with diameters of 17.5 ± 1.3 mm and concentric rings of pigmentation. Isolate T4 of P. griseola f. mesoamericana presented smaller colonies (9.9 ± 0.3 mm) with a uniform dark-gray color. Both isolates, S3b and T4, produced the same pigment,
a 1,8-dihydroxynaphthalene-melanin, although different in quantity and structural features as suggested by the IR spectrum.
The P. griseola f. griseola isolate S3b had a higher growth rate and melanin content as well as smaller sensitivity to melanin synthesis inhibitors compared
to the isolate T4 of P. griseola f. mesoamericana. These results suggest a possible link between melanin and growth in P. griseola. 相似文献
16.
17.
QTL Mapping for Frond Length and Width in Laminaria japonica Aresch (Laminarales, Phaeophyta) Using AFLP and SSR Markers 总被引:1,自引:0,他引:1
Fuli Liu Zhanru Shao Haining Zhang Jidong Liu Xiuliang Wang Delin Duan 《Marine biotechnology (New York, N.Y.)》2010,12(4):386-394
In Laminaria japonica Aresch breeding practice, two quantitative traits, frond length (FL) and frond width (FW), are the most important phenotypic
selection index. In order to increase the breeding efficiency by integrating phenotypic selection and marker-assisted selection,
the first set of QTL controlling the two traits were determined in F2 family using amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers. Two prominent L. japonicas inbred lines, one with “broad and thin blade” characteristics and another with “long and narrow blade” characteristics, were
applied in the hybridization to yield the F2 mapping population with 92 individuals. A total of 287 AFLP markers and 11 SSR markers were used to construct a L. japonica genetic map. The yielded map was consisted of 28 linkage groups (LG) named LG1 to LG28, spanning 1,811.1 cM with an average
interval of 6.7 cM and covering the 82.8% of the estimated genome 2,186.7 cM. While three genome-wide significant QTL were
detected on LG1 (two QTL) and LG4 for “FL,” explaining in total 42.36% of the phenotypic variance, two QTL were identified
on LG3 and LG5 for the trait “FW,” accounting for the total of 36.39% of the phenotypic variance. The gene action of these
QTL was additive and partially dominant. The yielded linkage map and the detected QTL can provide a tool for further genetic
analysis of two traits and be potential for maker-assisted selection in L. japonica breeding. 相似文献
18.
Genetic variation within, and divergence among, populations of the liverwortConocephalum conicum were estimated from the study of 17 populations and 23 putative gene loci. Two additional multilocus genotypes (“T” and “FS”)
were detected in Japan, along with the previously reported “J” type. These three multilocus genotypes differed both morphologically
and ecologically. All eight populations from western Japan included only the J-type and exhibited low genetic variation within
populations: Nei's (1973) average gene diversity (Ĥ)=0.080±0.029. In contrast, co-occurrence of several multilocus genotypes in each population from the Kanto District resulted
in much higher levels of genetic variation (Ĥ=0.218±0.037). If the three genotypes are distinguished,Ĥ values are 0.113±0.030 for T-type, 0.107±0.033 for FS-type, and 0.083±0.018 for J-type. UsingC. japonicum, which showed low genetic variation (0.014±0.010) as an outgroup, each genotype formed a monophyletic clade, and the J- and
FS-types were more closely related to each other than to the T-type. Populations of western Japan and the Kanto District also
differed in the degree of gene diversity among populations, but the reasons for these differences are obscure. 相似文献
19.
Ging Kuo Wang Joanna Calderon Shiow-Jiin Jaw Sho-Ya Wang 《The Journal of membrane biology》2009,229(1):1-9
Articaine is widely used as a local anesthetic (LA) in dentistry, but little is known regarding its blocking actions on Na+ channels. We therefore examined the state-dependent block of articaine first in rat skeletal muscle rNav1.4 Na+ channels expressed in Hek293t cells. Articaine exhibited a weak block of resting rNav1.4 Na+ channels at −140 mV with a 50% inhibitory concentration (IC50) of 378 ± 26 μM (n = 5). The affinity was higher for inactivated Na+ channels measured at −70 mV with an IC50 value of 40.6 ± 2.7 μM (n = 5). The open-channel block by articaine was measured using inactivation-deficient rNav1.4 Na+ channels with an IC50 value of 15.8 ± 1.5 μM (n = 5). Receptor mapping demonstrated that articaine interacted strongly with a D4S6 phenylalanine residue, which is known
to form a part of the LA receptor. Thus the block of rNav1.4 Na+ channels by articaine is via the conserved LA receptor in a highly state-dependent manner, with a ranking order of open (23.9×) > inactivated
(9.3×) > resting (1×) state. Finally, the open-channel block by articaine was likewise measured in inactivation-deficient
hNav1.7 and rNav1.8 Na+ channels, with IC50 values of 8.8 ± 0.1 and 22.0 ± 0.5 μM, respectively (n = 5), indicating that the high-affinity open-channel block by articaine is indeed preserved in neuronal Na+ channel isoforms. 相似文献
20.
Ross Crates Laura Rayner Dejan Stojanovic Matthew Webb Aleks Terauds Robert Heinsohn 《Ibis》2019,161(3):521-532
Identifying factors influencing the demographics of threatened species is essential for conservation, but a lack of comprehensive demographic data often impedes the effective conservation of rare and mobile species. We monitored breeding of critically endangered and semi‐nomadic Regent Honeyeaters Anthochaera phrygia (global population c. 100 pairs) over 3 years throughout their range. Overall nest success probability (0.317) was highly spatially variable and considerably lower than previous estimates for this (and many other honeyeater) species, as was productivity of successful nests (mean 1.58 juveniles fledged). Nest surveillance revealed high predation rates by a range of birds and arboreal mammals as the primary cause of nest failure. An estimated 12% of pairs either failed to establish a territory or their nests did not reach the egg stage. We also found a male bias to the adult sex ratio, with an estimated 1.18 males per female. Juvenile survival for the first 2 weeks after fledging was high (86%). Management interventions that aim to increase nest success in areas of low nest survival must be investigated to address an apparent decline in reproductive output and avoid extinction of the Regent Honeyeater. We show that temporal and spatial variation in the breeding success of rare and highly mobile species can be quantified with robust population monitoring using sampling regimens that account for their life histories. Understanding the causes of spatio‐temporal variation in breeding success can enhance conservation outcomes for such species through spatially and temporally targeted recovery actions. 相似文献