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1.
This study was conducted to compare in vitro development of bovine morulae in Ham's F-10 and Dulbecco's phosphate buffered saline (D-PBS) media supplemented with 10% (v/v) normal steer serum. Fifty-three excellent and good embryos were obtained by superovulating 15 non-lactating Holstein cows. Embryos were placed randomly in culture with Ham's F-10 or D-PBS media and development was recorded at 12-h intervals for the duration of culture. All embryos reached early blastocyst, blastocyst and expanded blastocyst stage. Nineteen of 27 embryos (70.1%) cultured in Ham's F-10 developed to hatched blastocyst stage in contrast to three out of 26 in D-PBS (11.5%). The mean developmental scores at 24, 48, 72, 96 and 120 h of culture were significantly (P<0.001) higher for embryos cultured in Ham's F-10. Also, the mean times to reach early blastocyst (25.84 +/- 6.65 vs 46.67 +/- 9.99 h), blastocyst (44.57 +/- 11.45 vs 61.89 +/- 16.62 h) and expanded blastocyst stage (65.00 +/- 13.20 vs 73.41 +/- 15.80 h) were significantly (P<0.001) shorter for embryos cultured in Ham's F-10. No difference was observed in the mean time to reach hatching (90.00 +/- 10.85 vs 84.00 +/- 16.97 h) and hatched blastocyst stage (97.26 +/- 18.71 vs 96.00 +/- 0.00 h). The results obtained support the concept that Ham's F-10 and normal steer serum provide for optimal bovine embryo development and suggest that 10% normal steer serum could be used as a protein supplement with D-PBS for short term storage and culture of bovine embryos.  相似文献   

2.
Interpreting diel hysteresis between soil respiration and temperature   总被引:1,自引:0,他引:1  
Increasing use of automated soil respiration chambers in recent years has demonstrated complex diel relationships between soil respiration and temperature that are not apparent from less frequent measurements. Soil surface flux is often lagged from soil temperature by several hours, which results in semielliptical hysteresis loops when surface flux is plotted as a function of soil temperature. Both biological and physical explanations have been suggested for hysteresis patterns, and there is currently no consensus on their causes or how such data should be analyzed to interpret the sensitivity of respiration to temperature. We used a one‐dimensional soil CO2 and heat transport model based on physical first principles to demonstrate a theoretical basis for lags between surface flux and soil temperatures. Using numerical simulations, we demonstrated that diel phase lags between surface flux and soil temperature can result from heat and CO2 transport processes alone. While factors other than temperature that vary on a diel basis, such as carbon substrate supply and atmospheric CO2 concentration, can additionally alter lag times and hysteresis patterns to varying degrees, physical transport processes alone are sufficient to create hysteresis. Therefore, the existence of hysteresis does not necessarily indicate soil respiration is influenced by photosynthetic carbon supply. We also demonstrated how lags can cause errors in Q10 values calculated from regressions of surface flux and soil temperature measured at a single depth. Furthermore, synchronizing surface flux and soil temperature to account for transport‐related lags generally does not improve Q10 estimation. In order to calculate the sensitivity of soil respiration to temperature, we suggest using approaches that account for the gradients in temperature and production existing within the soil. We conclude that consideration of heat and CO2 transport processes is a requirement to correctly interpret diel soil respiration patterns.  相似文献   

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In malignant B lymphoma cells interleukin-10 (IL-10) expression is frequently upregulated. This effect is thought to support to the malignant transformation of these cells and to be a potential target for pharmacotherapy. To define better the mechanism for upregulation of the IL-10 gene, we tested the association between IL-10 and p38 mitogen-activated protein kinase (MAPK) in several Epstein-Barr virus (EBV) infected and non-infected Burkitt's lymphoma (BL) cell lines. The all BL cell lines expressed IL-10 and IL-10 receptor mRNAs, and produced IL-10. p38 MAPK was constitutively phosphorylated in the cytoplasm of the BL cell lines. We further analyzed molecular effects of p38 MAPK on IL-10 expression in Akata cells. Exogenous IL-10 lead rapidly to phosphorylation of Jak1 and Tyk2 as transducers of signals of IL-10, and promoted growth of Akata cells in a dose-dependent manner. The phosphorylation of cytoplasmic p38 MAPK in Akata cells was reduced by the serine/threonine kinase inhibitor, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H7). A specific inhibitor of p38 MAPK, SB203580, blocked simultaneously STAT3 DNA-binding activity, and IL-10 mRNA expression, IL-10 production, and then the cell growth was inhibited. These results indicate that the p38 MAPK pathway is functionally linked to IL-10 gene expression and supports the view that the constitutive activation of cytoplasmic p38 MAPK in BL cells is a step in the upregulation of IL-10 gene expression and lymphomagenesis.  相似文献   

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影响籼粳稻DNA限制性片段长度多态性检测的因素分析   总被引:1,自引:0,他引:1  
对窄叶青(籼稻)和京系17(梗稻)的RFLP进行了系统分析。结果表明,某种酶多态性检测能力与同时检测到此多态性的其余酶的数目之间存在极显著的正相关(r=0.962**)。由此推论,籼粳稻大部分RFLP可能来自大范围DNA的结构变化而不是碱基取代。cDNA克隆虽然具有高度的保守性,但却具有比基因组克隆更高的多态性检测能力。在实验使用的探针范围内,探针长度和检测到的多态性无相关性。由探针检测到的多态性位点均匀地散布在水稻的12对染色体上,这可能是这两个品种所属的亚种之间的遗传距离较大的原因。  相似文献   

8.
The main objective of this research was to assess genotype?×?environment interactions and the stability status of 24 Hevea clones along with 2 checks in terms of latex yield and girth growth under two different environmental conditions representing for traditional and non-traditional rubber growing regions of Vietnam. Genotype?×?environment interactions were found to be highly significant for both latex yield and girth at opening, indicating that the latex yield and girth growth of the studied rubber clones were significantly affected by the environmental conditions of the location. Stability analyses indicated that LH 94/359, LH 91/579 and LH 94/481 were the best clones for highest latex yield and adaptability to traditional, non-traditional and both rubber growing regions of Vietnam, respectively. In terms of girth at opening, the stability analyses revealed that these clones were also accepted as the average girth growth and adaptability to both rubber growing regions of Vietnam.  相似文献   

9.
In cultures of hamster fibroblasts (BHK cell line) treated with potassium dichromate (K2Cr2O7) nucleic acid and protein syntheses are differentially inhibited, and nucleoside uptake into the intracellular pool is characterized by a stimulation phase followed by an inhibition phase. Different patterns are observed for the uptake of each ribo- and deoxyribonucleoside, pyrimidine nucleoside (particularly deoxycytidine) uptake reaching the highest stimulation level. Kinetics of thymidine and deoxycytidine initial uptake at different exogenous nucleoside concentrations show that K2Cr2O7 affects both simple and facilitated diffusion of nucleosides. The time course of thymidine and deoxycytidine pool saturation suggests however that the effects of K2Cr2O7 on plasma membrane permeability are partially counterbalanced by modifications of pool size deriving from the concomitant alteration of steps of nucleoside metabolism separate from nucleoside uptake.  相似文献   

10.
Sequence heterogeneity at the ends of mature microRNAs (miRNAs) is well documented, but its effects on miRNA function are largely unexplored. Here we studied the impact of miRNA 5′-heterogeneity, which affects the seed region critical for target recognition. Using the example of miR-142-3p, an emerging regulator of the hematopoietic lineage in vertebrates, we show that naturally coexpressed 5′-variants (5′-isomiRs) can recognize largely distinct sets of binding sites. Despite this, both miR-142-3p isomiRs regulate exclusive and shared targets involved in actin dynamics. Thus, 5′-heterogeneity can substantially broaden and enhance regulation of one pathway. Other 5′-isomiRs, in contrast, recognize largely overlapping sets of binding sites. This is exemplified by two herpesviral 5′-isomiRs that selectively mimic one of the miR-142-3p 5′-isomiRs. We hypothesize that other cellular and viral 5′-isomiRs can similarly be grouped into those with divergent or convergent target repertoires, based on 5′-sequence features. Taken together, our results provide a detailed characterization of target recognition by miR-142-3p and its 5′-isomiR-specific viral mimic. We furthermore demonstrate that miRNA 5′-end variation leads to differential targeting and can thus broaden the target range of miRNAs.  相似文献   

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For over 100 years, Morgan's Canon has served as the criterion for distinguishing what appears to be complex cognitive processes shown by animals from simpler associative learning processes (Pavlovian and instrumental conditioning). Morgan's ( 1894 ) canon states “In no case is an animal activity to be interpreted in terms of higher psychological processes if it can be fairly interpreted in terms of processes which stand lower in the scale of psychological evolution and development.” In the present article, several examples are provided in which complex human‐like processes are proposed to have been demonstrated but the judicious use of Morgan's Canon suggests that simpler mechanisms may be sufficient to account for the behavior. The use of Morgan's Canon is not meant to reduce behavior to its lowest common denominator but rather to challenge investigators to develop procedures that can distinguish between simple behavioral principles and the more complex processes that cannot be explained in terms of genetics or simple conditioning. Whatever the results of these experiments, they should help identify the underlying processes and mechanisms involved.  相似文献   

12.
Ecogeographic rules that describe quantitative relationships between morphologies and climate might help us predict how morphometrics of animals was shaped by local temperature or humidity. Although the ecogeographic rules had been widely tested in animals of Europe and North America, they had not been fully validated for species in regions that are less studied. Here, we investigate the morphometric variation of a widely distributed East Asian passerine, the vinous‐throated parrotbill (Sinosuthora webbiana), to test whether its morphological variation conforms to the prediction of Bergmann''s rule, Allen''s rules, and Gloger''s rule. We at first described the climatic niche of S. webbiana from occurrence records (n = 7838) and specimen records (n = 290). The results of analysis of covariance (ANCOVA) suggested that the plumage coloration of these parrotbills was darker in wetter/warmer environments following Gloger''s rule. However, their appendage size (culmen length, beak volume, tarsi length) was larger in colder environments, the opposite of the predictions of Allen''s rule. Similarly, their body size (wing length) was larger in warmer environments, the opposite of the predictions of Bergmann''s rule. Such disconformity to both Bergmann''s rule and Allen''s rule suggests that the evolution of morphological variations is likely governed by multiple selection forces rather than dominated by thermoregulation. Our results suggest that these ecogeographic rules should be validated prior to forecasting biological responses to climate change especially for species in less‐studied regions.  相似文献   

13.
The induction of an in vitro T cell response against tumour-associated antigens with subsequent expansion of the individual cytotoxic T lymphocyte (CTL) clones still is not routine and the only tumour-associated antigen that has been found to easily induce the establishment of CTL clones is the MART-1/Melan-A antigen. In this paper, we describe a new approach for in vitro immunization based on the use of preselected melanoma cell clones. The human melanoma cell subline FM3.P was cloned and the immunological properties of individual clones were compared. Melanoma cell clone FM3.29, having a high level of expression of melanoma differentiation antigens, as well as high levels of the HLA class I and class II antigens and adhesion molecules, was used for the establishment of a CTL line that was subsequently cloned. For optimization of the conditions of growth of established CTL clones, a particular melanoma subline FM3.D/40 was selected for supporting the proliferation of CTL clones. The majority of the established CTL clones recognized the melanoma-associated differentiation antigens gp100 and MART-1/Melan-A. Epitope analysis indicated that two different epitopes derived from gp100 (154-162 and 280-288) and a single epitope from MART-1/Melan-A (27 35) were recognized by these CTL clones. The gp100-specific CTL clones were found to be significantly more sensitive to the culture conditions than the MART-1/Melan-A-specific CTL clones. In addition, the presence of excess peptide in the culture medium induced autokilling of the gp100-specific, but not the MART-1/Melan-A-specific CTL clones. Taken together, these results demonstrate that, by careful preselection of melanoma cell lines and clones both for the induction of CTL line from patients' peripheral blood lymphocytes and subsequent cloning, it is possible to obtain a large number of stable CTL clones even against such an inherently "difficult" differentiation antigen as gp100.  相似文献   

14.
A new model for estimating human body surface area and body volume/mass from standard skeletal metrics is presented. This model is then tested against both 1) “independently estimated” body surface areas and “independently estimated” body volume/mass (both derived from anthropometric data) and 2) the cylindrical model of Ruff. The model is found to be more accurate in estimating both body surface area and body volume/mass than the cylindrical model, but it is more accurate in estimating body surface area than it is for estimating body volume/mass (as reflected by the standard error of the estimate when “independently estimated” surface area or volume/mass is regressed on estimates derived from the present model). Two practical applications of the model are tested. In the first test, the relative contribution of the limbs versus the trunk to the body's volume and surface area is compared between “heat-adapted” and “cold-adapted” populations. As expected, the “cold-adapted” group has significantly more of its body surface area and volume in its trunk than does the “heat-adapted” group. In the second test, we evaluate the effect of variation in bi-iliac breadth, elongated or foreshortened limbs, and differences in crural index on the body's surface area to volume ratio (SA:V). Results indicate that the effects of bi-iliac breadth on SA:V are substantial, while those of limb lengths and (especially) the crural index are minor, which suggests that factors other than surface area relative to volume are driving morphological variation and ecogeographical patterning in limb prorportions. Am J Phys Anthropol 156:614–624, 2015. © 2014 Wiley Periodicals, Inc.  相似文献   

15.
The green anole, Anolis carolinensis, has long been an important model organism for studies of physiology and behaviour, and recently became the first reptile to have its genome sequenced. With a large and environmentally heterogeneous distribution, especially in relation to well‐studied Antillean relatives, A. carolinensis is also emerging as an important organism for novel studies of geographical differentiation and adaptation. In the present study, we quantify the degree of morphological variation in this species and test for environmental correlates of this variation. We also examine adherence to Bergmann's and Allen's rule, two eco‐geographical principles that have been well studied over large species ranges. We sampled from 14 populations across the distribution of the species in North America and measured 28 distinct morphological traits. We also collected a suite of environmental variables for each site, including those related to temperature, precipitation, and vegetation. Ultimately, we found a large degree of geographical variation in morphology, with head traits contributing the most to differences among populations. Morphological variation was correlated with variation in temperature, precipitation, and latitude across sites. We found no support for reverse Bergmann's rule typical of squamates, although we did find a trend of reverse Allen's rule. Ultimately, the present study provides a novel look at A. carolinensis and establishes it as a strong candidate for further studies of variation and adaptation over a large range.  相似文献   

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Abstract

Posttranslational modifications (PTM) including glycosylation, phosphorylation, acetylation, methylation and ubiquitination dynamically alter the proteome. The evolutionarily conserved enzymes O-linked N-acetylglucosamine (O-GlcNAc) transferase (OGT) and O-GlcNAcase are responsible for the addition and removal, respectively, of the nutrient-sensitive PTM of protein serine and threonine residues with O-GlcNAc. Indeed, the O-GlcNAc modification acts at every step in the “central dogma” of molecular biology and alters signaling pathways leading to amplified or blunted biological responses. The cellular roles of OGT and the dynamic PTM O-GlcNAc have been clarified with recently developed chemical tools including high-throughput assays, structural and mechanistic studies and potent enzyme inhibitors. These evolving chemical tools complement genetic and biochemical approaches for exposing the underlying biological information conferred by O-GlcNAc cycling.  相似文献   

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In this paper, Shannon's measure of uncertainty is explored in the analysis of cancer data. The term ‘cancer diversity’ is defined and its potential application is illustrated.  相似文献   

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Baker's yeast immobilized on montmorillonite K10 and chrysotile reduced α-azidopropiophenone to the corresponding azidoalcohols syn and anti with good chemical yield and enantiomeric excess.  相似文献   

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