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1.
In this study, objective differences between the Cold (Han) and Hot (Re) nature of traditional Chinese medicines, e.g. Strobal and Rhubarb, are determined by using a cold/hot plate differentiation technology. A novel, self-designed cold/hot plate differentiating instrument, with methodological study, was used to investigate the intervention of Strobal and Rhubarb on the temperature tropism of mice. Compared with the ICR and BALB/c mice, it was found that KM mice on the cold/hot plate were more sensitive to the change of temperature, within the tolerant temperature range of 15—40℃. The temperature tropism behavior of mice is influenced by treatment with Rhubarb and Strobal, as is the activity of ATPase in liver tissue. These trends are consistent with the definition of the Cold/Hot nature of Chinese medicines based on traditional Chinese medicinal theory. This study showed that the differences of the Cold/Hot nature of traditional Chinese medicines. might be objectively represented by the temperature tropism of animal by means of cold/hot differentiating assay.  相似文献   

2.
Drosophila suzukii is an invasive pest causing severe damages to a large panel of cultivated crops.To facili tate its biocontrol with stratcgies such as sterile or incompatible insect techniques,D.suzukid must be mass-produced and then stored and transported under low temperature.Prolonged cold exposure induces chill injuries that can be mitigated if the cold period is interrupted with short warming intervals,referred to as fluctuating thermal regimes(FTR).In this study,we tested how to optimally use FTR to extend the shelf life of D.suzukii under cold storage.Several FTR parameters were asessed:temperature(15,20,25℃),duration(0.5,1,2,3 h),and frequency(every 12,24,36,48 h)of warming intervals,in two wild-type lines and in two developmental stages(pupac and adults).Generally,FTR improved cold storage tolerance with respect to constant low temperatures(CLT).Cold mortality was lower when recovery temperature was 20℃ or higher,when duration was 2 h per day or longer,and when warming interruptions occurred frequently(every 12 or 24 h).Applying an optimized FTR protocol to adults greatly reduced cold mortality over long-term storage(up to 130 d).Consequences of FTR on fitness-related traits were also investigated.For adults,poststorage survival was unaffected by FTR,as was the case for female fecundity and male mating capacity.On the other hand,when cold storage occurred at pupal stage,postorage survival and male mating capacity were altered under CLT,but not under FTR.After storage of pupae,female fecundity was lower under FTR compared to CLT,suggesting an energy trade-off between repair of chill damages and C22 production.This study provides detailed information on the application and optimization of an FTR-based protocol for cold storage of D.suzuki that could be useful for the biocontrol of this pest.  相似文献   

3.
Glycogen constitutes the major carbon storage source in cyanobacteria, as starch in algae and higher plants. Glycogen and starch synthesis is linked to active photosynthesis and both of them are degraded to glucose in the dark to maintain cell metabolism. Control of glycogen biosynthesis in cyanobacteria could be mediated by the regulation of the enzymes involved in this process, ADP-glucose pyrophosphorylase (AGP) and glycogen synthase, which were identified as putative thioredoxin targets. We have analyzed whether both enzymes were subjected to redox modification using purified recombinant enzymes or cell extracts in the model cyanobacterium Synechocystis sp. PCC 6803. Our results indicate that both AGP and glycogen synthases are sensitive to copper oxidation. However, only AGP exhibits a decrease in its enzymatic activity, which is recovered after reduction by DTT or reduced thioredoxin (TrxA), suggesting a redox control of AGP. In order to elucidate the role in redox control of the cysteine residues present on the AGP sequence (C45, C185, C320, and C337), they were replaced with serine. All AGP mutant proteins remained active when expressed in Synechocystis, although they showed different electrophoretic mobility profiles after copper oxidation, reflecting a complex pattern of cysteines interaction.  相似文献   

4.
Since the middle of the 19th century, the area covered by forests in France has doubled. These new forests grow on previous agricultural lands. We have studied the influence of this agricultural history on the 15N abundance of present-day forests planted on farmlands in the Vosges mountains (north-eastern France) between 1898 and 1930. Different types of land use were identified from old cadastres (1814–1836) of 16 farms. Ancient forests adjacent to farmlands were used as controls. Former pastures, meadows, croplands, gardens and ancient forests were compared for soil δ15N (fraction <50 μm and total soil), C/N, P and N content and fern (Dryopteris carthusiana) δ15N. The mean δ15N of soil increased in the order ancient forests (+0.0‰)<pastures (+1.4‰)<croplands (+1.6‰)<meadows (+2.5‰)<gardens (+3.8‰). This increase in soil δ15N with the intensity of former land use was related to the former input of 15N-enriched manure, and to an activation of soil nitrification leading to 15N-depleted nitrate export on previously manured parcels. Fern δ15N increased in the same order as soil δ15N in relation to past land use. The mean δ15N of fern in ancient forests (–4.4‰) and former pastures (–3.4‰) was 5‰ lower than soil δ15N and the two variables were strongly correlated. The δ15N of fern in formerly manured parcels varied little (cropland: –2.7‰, meadows: –2.6‰ and gardens: –2.2‰) and independently of soil δ15N, suggesting that the soil sources of fern N differed between unmanured and manured parcels. Understorey plant δ15N and soil δ15N appear to be excellent tracers of previous land use in forests, and could be used in historical studies. The persistence of high isotopic ratios in previously manured parcels, almost a century after afforestation, suggests a long-term influence of former land use on the N cycle in forest soils. Received: 22 January 1999 / Accepted: 22 July 1999  相似文献   

5.
The embryonic diapause of the silkworm, Bombyx mori, is induced by the diapause hormone (DH) which is secreted from the suboesophageal ganglion of pupae. The diapause nature of bivoltine strains uses environmental stimuli as the initial signal to determine the diapause nature. The experiments showed that DH gene expression is a direct response to the environmental stimulus, such as high incubation temperature. The cDNA from the embryonic stage was cloned and sequence analysis showed the cDNA encoding DH. Expression patterns of the DH gene in embryonic stage are different at incubation temperatures 15℃ and 25℃, suggesting that the incubation temperature as an environmental signal is kept within the body to control the DH gene expression at the pupal stage, so that the embryonic diapause of next generation can be determined.  相似文献   

6.
The aim of this study was to investigate the role of β-adrenergic receptors in modulating associative long-term depression (LTD) at CA1 synapses in rat hippocampal slices. Standard extracellular electrophysiological techniques were employed to record field excitatory post-synaptic potential (fEPSP) activity and to induce associative LTD. Two independent Schaffer collateral pathways were elicited in hippocampal CA1 areas. In one (weak) pathway, the stimulating intensity was adjusted to elicit small fEPSP activity (20–30% of the maximum response). In contrast, 80–90% of the maximum response was evoked in the other (strong) pathway. Associative LTD of weak pathway could be induced by paired stimulation of weak and the strong pathways, repeated 100 times at 0.167 Hz. The associative LTD of weak pathway was NMDA receptor- and phophatase 2B dependent, because bath application of 50 μM D, L-AP5 or 10 μM cypermethrin blocked its induction. Bath application of 1 μM isoproterenol inhibited associative LTD, and this effect was blocked by timolol, suggesting the involvement of β-adrenergic receptors. The inhibitory effect of β-adrenergic receptors on LTD induction was blocked in slices pretreated with inhibitors of protein kinase A and mitogen-activated protein kinase, suggesting that these signal cascades are downstream effectors following activation of β-adrenergic receptors. Nevertheless, bath application of timolol or cypermethrin alone did not have significant effect on associative LTD induction, suggesting neither endogenous function of β-adrenergic receptor nor endogenous PKA activity does have a role in associative LTD induction.  相似文献   

7.
The D2 variable region of 28S ribosomal RNA was sequenced from ethanol specimens or obtained from the literature to provide the first phylogenetie reconstruction of the subfamily Euphorinae (Hymenoptera;Braconidae). Phylogenetic relationships were established by comparing the results using two different methods (distance-based neighbor-joining, NJ; and maximum parsimony, MP) and three different outgroups. The monophyly of the Euphorinae is well supported by all trees generated from molecular data. All phylogenetic reconstructions yielded trees with very similar topologies that only partially resolved the morphologically defined tribes and the relationships within the subfamily. We found no evidence for the monophyletic natures of the tribes Euphorinl, Dinocampini,Perilitini, Syntretini, Comsophorini and Centisitini, but we did find some evidence for the tribes Meteorini and Microctonini. The monophyletic nature of the tribe Meteodnl was well-supported in all trees. We also found the clade containing the LecythodeUa,Microctonus, Orionis and Streblocera to be a monophyletic group, which corresponded to the tribe Microtonini, with Orionis transferred from the tribe Eupholini into Microtonini.Among the genera of Euphorini our results showed strong support for a paraphyletic nature of this group, which can be roughly divided into two clades, one consisting of Aridelus Wesmaelia, the other of Leiophron Peristenus, suggesting both of which may be given tribal rank. The placement of the genus Chrysopophorus is largely uncertain. Two clades,Dinocampus Perilitus and Cosmophorus Rhopalophorus, were constantly resolved in our analyses, with 42-96 and 97-100 bootstrap value support, respectively, suggesting that both of them form monophyletic groups. For members of the Centistini, Pygostolus may be removed and included in Microctonini or other relative tribe.  相似文献   

8.
The status of the names, Physalis minima L. and P. maxima Mill. (Solanaceae), and their alleged presence on the Indian subcontinent are discussed. The issues of nativity and identity of Linnaean Physalis minima are long-debated while the use of the name P. maxima Mill. and its report from India are recent. The available evidence indicates that the name "P. minima L." is misapplied to two different elements, viz., P. angulata L. and P. lagascae Roem. & Schult. The name Physalis minima L. may be rejected as nomen confusum, for which the paper provides the primary information. As on today, it is submerged under the synonymy of P. angulata L. The correct name for the widely known P. minima is P. lagascae. The name "P. maxima Mill." applied to the escape and naturalized weed in the Indian subcontinent and elsewhere is to be substituted by P. pruinosa L., a name misapplied to P. grisea (Waterf.) M. Martínez.  相似文献   

9.
<正>Filamentous fungi are one of the major sources of natural products (NPs; which are also termed as secondary metabolites (SMs)) with diverse biological activities, which have been widely used in agriculture, industry, and pharmaceuticals. Fungi are the second largest species in nature, and their biodiversity implies genomic diversity, which, in turn,predicts the structural diversity of metabolites. In general,  相似文献   

10.
Platelet-derived growth factor (PDGF), abundant in bone tissue, has been reported to stimulate mesenchymal cell proliferation and migration. To elucidate the functional roles of PDGF during fracture healing, we investigated the expression of PDGF-A and -B chain proteins and receptor α and β mRNAs in fractured mouse tibiae. Twelve-week-old male BALB/c mice were operated on to make a closed fracture on the proximal tibia. On days 2, 4, 7, 10, 14, 21, and 28 after the operation, the fractured tibiae were excised, fixed with 4% paraformaldehyde, decalcified with 20% EDTA, and embedded in paraffin to prepare 7-μm sections. Immunohistochemistry using polyclonal antibodies against human PDGF-A and -B chains was carried out by the avidin-biotin-peroxidase method. For in situ hybridization, we used digoxigenin-labeled single-stranded DNA probes specific for mouse PDGF receptors α and β generated by unidirectional polymerase chain reaction. In the inflammatory phase on days 2–4 after the fracture, mesenchymal cells gathering at the fracture site expressed the PDGF-B chain and β receptor mRNA. At the stage of cartilaginous callus formation on day 7, the immunoreactivity for PDGF-A and -B chains on proliferating and hypertrophic chondrocytes and the signals of α and β receptor mRNAs on proliferating chondrocytes became manifest. At the stage of bony callus and bone remodeling on days 14–21, the predominant expression of the PDGF-B chain and β receptor was observed on both osteoclasts and osteoblasts. On day 28, signals for PDGF ligand proteins and receptor mRNAs diminished. The coincidental localization of PDGF ligands and their receptors implies a paracrine and autocrine mechanism. Our data suggested that PDGF contributed in part to the promotion of the chondrogenic and osteogenic changes of mesenchymal cells from the early to the midphase of fracture healing; the functions mediated by the β receptor, including cell migration, might be prerequisites to the recruitment of mesenchymal cells in the initial step and to the interaction between osteoclasts and osteoblasts in the bone remodeling phase. Accepted: 2 June 1999  相似文献   

11.
Crystals of pokeweed antiviral protein (PAP) from seeds of Phytolacca americana with high diffraction ability were grown from high protein concentration (100 mg/mL) solution at high temperature (33℃). The crystal structure was solved by use of molecular replacement method and refined by use of molecular dynamic method at 0 25 nm to an R factor of 18.15% with standard deviations from standard geometry of 0.001 6 nm and 2.04° for bond lengths and bond angles, respectively. Comparison with two other PAPs revealed, near the active center, a sequence and structure variable region, consisting of the loop connecting the fifth β strand with the second α helix and including a proposed active residue, suggesting this loop probably to be related to difference in activity.$$$$  相似文献   

12.
Establishing non-human primate models of human diseases is an efficient way to narrow the large gap between basic studies and translational medicine. Multifold advantages such as simplicity of breeding, low cost of feeding and facility of operating make the tree shrew an ideal non-human primate model proxy. Additional features like vulnerability to stress and spontaneous diabetic characteristics also indicate that the tree shrew could be a potential new animal model of human diseases. However, basal physiological indexes of tree shrew, especially those related to human disease, have not been systematically reported. Accordingly, we established important basal physiological indexes of domesticated tree shrews including several factors: (1) body weight, (2) core body temperature and rhythm, (3) diet metabolism, (4) locomotor rhythm, (5) electroencephalogram, (6) glycometabolism and (7) serum and urinary hormone level and urinary cortisol rhythm. We compared the physiological parameters of domesticated tree shrew with that of rats and macaques. Results showed that (a) the core body temperature of the tree shrew was 39.59±0.05 °C, which was higher than that of rats and macaques; (b) Compared with wild tree shrews, with two activity peaks, domesticated tree shrews had only one activity peak from 17:30 to 19:30; (c) Compared with rats, tree shrews had poor carbohydrate metabolism ability; and (d) Urinary cortisol rhythm indicated there were two peaks at 8:00 and 17:00 in domesticated tree shrews, which matched activity peaks in wild tree shrews. These results provided basal physiological indexes for domesticated tree shrews and laid an important foundation for diabetes and stress-related disease models established on tree shrews.  相似文献   

13.
Nembrini  G.  Capobianco  J. A.  Garcia  J.  Jacquet  J. -M. 《Hydrobiologia》1982,91(1):363-375
The pore fluids of the sediments collected at the deepest point of Lac Léman (Switzerland) are supersaturated with respect to vivianite and siderite. In the presence of sulphide, the iron solubility is controlled entirely by the amorphous iron sulphides. As the iron (II) becomes dominant, the formation of siderite occurs and evidence of this, in the solid phase, can be obtained by the use of M?ssbauer spectroscopy and some sequential chemical extractions. The amount of ‘siderite iron’ decreases from about 10% near the sediment surface to a few percent in the lower levels of the sediment (<10 cm). Evidence for vivianite formation could not be obtained even in the lower layers, despite the precautions taken to avoid oxidation. Although the trace metal behaviour in the solid phase is well correlated with the iron and manganese, availability in the pore fluid is dependent on the adsorption on, or co-precipitation with, finely dispersed colloids, which pass through a 0.45 μg filter. Trace metal concentrations in pore fluid were not directly related to total elemental concentrations in the solid phase, and did not reflect cumulative trends associated with anthropogenic enrichment.  相似文献   

14.
Aims: Variations and potential trade-offs of leaf hydraulic and photosynthetic traits are essential for assessing and predicting the effect of climate change on tree survival, growth and distribution. Our aims were to examine variations and interrelationships of leaf hydraulic and photosynthetic traits in response to changes in site conditions for Dahurian larch (Larix gmelinii)-a dominant tree species in Chinese boreal forests. Methods: This study was conducted at the Maoershan Forest Ecosystem Research Station. A transect of 27 year-old Dahurian larch plantation was established that consisted of five plots extending from the valley to the ridge of a slope. The predawn leaf water potential (ψpre), area- and mass-based leaf hydraulic conductance (Karea and Kmass, respectively), resistance to embolism capacity (P50), leaf mass per area (LMA), net photosynthetic rate (A), and leaf nitrogen content (N) were measured in August 2016. Important findings: The ψpre, Karea, Kmass, P50, A, LMA, and N all varied significantly among the plots (p < 0.05), indicating significant intra-specific variations in these traits in response to the changes in site conditions. The P50 was significantly (p < 0.05) correlated with ψpre, Karea or Kmass, suggesting that a trade-off between hydraulic efficiency and safety exist within the species to some degree. There were significant (p < 0.05) pairwise correlations between A, LMA, and N. Nevertheless, there was no significant (p < 0.05) correlation between the measured photosynthetic traits and hydraulic traits. We concluded that the intra-specific variations and multiple interrelationships of the leaf hydraulic and photosynthetic traits for the larch reflect the plasticity of its leaf traits and strategies of its survival and growth as a result of its acclimation to diverse site conditions.  相似文献   

15.
The photochemical activity of native Central Siberian Scots pine trees (Pinus sylvestris L) was estimated from the middle of February to the middle of March 2001. We measured chlorophyll (Chl) fluorescence in attached intact needles from trees located approx. 30 km west of the Yenisey river (60°44′N, 89°09′E) near the village of Zotino. In this period, the air temperature varied between −39 °C and +7 °C. At temperatures below −10 °C, P. sylvestris needles did not exhibit any variable Chl fluorescence during the daylight period. During the night, however, the effective quantum yield of photosystem 2 (PS2) photochemistry, Φ22 = (Fm′ − Ft)/Fm′), increased from values near zero to values between 0.05 and 0.20 depending on the needle temperature and sample investigated. The increase started soon after dusk and lasted for 3–6 h depending on the temperature. A faster increase of Φ2 was found for temperatures around −16 °C, and lower rates occurred at lower temperatures. Irrespective of the temperature, Φ2 decreased rapidly to near zero values at dawn, when the photosynthetic photon flux density increased to about 1–5 μmol m−2 s−1, and remained near zero throughout the day. At temperatures higher than −10 °C, the diurnal decrease and the nocturnal increase of Φ2 were less distinct or disappeared completely. Hence the winter-adapted Scots pine maintains some photochemical activity of PS2 even at extremely cold temperatures. The capacity of photochemical reactions below −10 °C is, however, very limited and PS2 photochemistry is saturated by an extremely low irradiance (less than 5 μmol m−2 s−1).  相似文献   

16.
Yang L M  Han M  Zhou G S  Li J D 《农业工程》2007,27(1):16-23
Leymus chinensis is a keystone species in the temperate zone grassland of China. Along the NECT (Northeast China Transect) in 2001, water-use efficiency of L. chinensis was analyzed with δ13C, and changes in the stoma density of its leaves were observed and computed under a microscope. Results showed that the ecological plasticity modulation of the stoma density of L. chinensis and its water-use efficiency were two important mechanisms for its broad ecological adaptability. From east to west along the NECT, the δ13C of the species varied from -27.49‰ to -23.57‰, consisting with the reduction of annual precipitation, soil water and annual average temperature, but increased with the increase of the elevation of sampling sites. The stoma density increased from 96.9/mm2 to 169.5/mm2, indicating that the water-use efficiency for the species was improved along the gradient. The linear coefficient between the two parameters was significant (R2 = 0.7338). The results of a stepwise regression analysis showed that the soil water was the first marked factor for determining the stoma density, and the next was the annual precipitation, which suggested that the water factors were the primary ecological factors influencing the stoma density of L. chinensis. The findings in this study showed that the responses of the stoma density and the water-use efficiency for L. chinensis to environmental changes were very complicated. They may be the outcome operated synthetically by all environmental factors in the long-term adaptation to different ecological environments, including human activity, for L. chinensis.  相似文献   

17.
We acclimated adults of two viviparous(Phrynocephalus guinanensis and P.vlangalii) and one oviparous(P.versicolor) species of toad-headed lizards(Agamidae) to 28 °C,33 °C and 38 °C to examine whether thermal preference(preferred body temperature,Tp) and thermal tolerance(critical thermal minimum,CTMin;critical thermal maximum,CTMax) were affected by acclimation temperature,and correlate with body size and habitat use.Both Tp and CTMax were highest in P.versicolor and lowest in P.vlangalii,with P.guinanensis in between.The two viviparous species did not differ in CTMin and thermal tolerance range,and they both were more resistant to low temperatures and had a wider range of thermal tolerance than the oviparous species.Both CTMin and CTMax shifted upward as acclimation temperature increased in all the three species.Tp was higher in the lizards acclimated to 33 °C than in those to 28 °C or 38 °C.The range of thermal tolerance was wider in the lizards acclimated to 28 °C than in those to 33 °C or 38 °C.The data showed that:1) thermal preference and tolerance were affected by acclimation temperature,and differed among the three species of Phrynocephalus lizards with different body sizes and habitat uses;2) both Tp and CTMax were higher in the species exchanging heat more rapidly with the environment,and CTMin was higher in the species using warmer habitats during the active season;and 3) thermal preference and tolerance might correlat with body size and habitat use in Phrynocephalus lizards.  相似文献   

18.
The developed method for mercury speciation analysis has been validated and used for the biomonitoring study of mercury species in human hair. Statistical evaluation proved the reliability of simplified determination of inorganic mercury (difference between total mercury and methylmercury). The results of the validation showed that the method is very well suitable for the determination of both species of mercury in hair for biomonitoring purposes. Non-exposed schoolchildren from three areas in the western and central part of the Czech Republic were chosen as the target group. Tenth of a microgram per gram of the total mercury were generally found in the analyzed hair; values higher than 1 μg g−1 were detected only exceptionally. Comparable results were obtained for two western areas and differed significantly from those for the third area located in the central part of the Czech Republic. In the areas examined, the mean methylmercury contents amounted to 23–46% of the total mercury in the hair. The results confirm an assumption that exposure to mercury does not pose a significant risk to the population in the Czech Republic.  相似文献   

19.
The discovery that adipose tissue represents an interesting source of multipotent stem cells has led to many studies exploring the clinical potential of these cells in cell-based therapies. Recent advances in understanding the secretory capacity of adipose tissue and the role of adipokines in the development of obesity and associated disorders have added a new dimension to the study of adipose tissue biology in normal and diseased states. Subcutaneous adipose tissue forms the interface between the clinical application of regenerative medicine and the establishment of the pathological condition of obesity. These two facets of adipose tissue should be understood as potentially related phenomena. Because of the functional characteristics of adipose stem cells, these cells represent a fundamental tool for understanding how these two facets are interconnected and could be important for therapeutic applications. In fact, adipose tissue stem cells have multiple functions in obesity related to adipogenic, angiogenic and secretory capacities. In addition, we have also previously described a predominance of larger blood vessels and an adipogenic memory in the subcutaneous adipose tissue after massive weight loss subsequent to bariatric surgery(ex-obese patients). Understanding the reversibility of the behavior of adipose stem cells in obeses and in weight loss is relevant to both physiological studies and the potential use of these cells in regenerative medicine.  相似文献   

20.
Leymus chinensis is a keystone species in the temperate zone grassland of China. Along the NECT (Northeast China Transect) in 2001, water-use efficiency of L. chinensis was analyzed with δ13C, and changes in the stoma density of its leaves were observed and computed under a microscope. Results showed that the ecological plasticity modulation of the stoma density of L. chinensis and its water-use efficiency were two important mechanisms for its broad ecological adaptability. From east to west along the NECT, the δ13C of the species varied from -27.49‰ to -23.57‰, consisting with the reduction of annual precipitation, soil water and annual average temperature, but increased with the increase of the elevation of sampling sites. The stoma density increased from 96.9/mm2 to 169.5/mm2, indicating that the water-use efficiency for the species was improved along the gradient. The linear coefficient between the two parameters was significant (R2 = 0.7338). The results of a stepwise regression analysis showed that the soil water was the first marked factor for determining the stoma density, and the next was the annual precipitation, which suggested that the water factors were the primary ecological factors influencing the stoma density of L. chinensis. The findings in this study showed that the responses of the stoma density and the water-use efficiency for L. chinensis to environmental changes were very complicated. They may be the outcome operated synthetically by all environmental factors in the long-term adaptation to different ecological environments, including human activity, for L. chinensis.  相似文献   

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