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排序方式: 共有42条查询结果,搜索用时 312 毫秒
11.
FTV Pereira FC Braga KC Burioli JR Kfoury Jr LJ Oliveira PC Papa AF Carvalho CE Ambrósio FW Bazer MA Miglino 《Reproduction in domestic animals》2010,45(5):907-914
The objectives of this investigation were to understand transplacental transport of iron by secreted uteroferrin (UF) and haemophagous areas of water buffalo placenta and clarify the role(s) of blood extravasation at the placental‐maternal interface. Placentomes and interplacentomal region of 51 placentae at various stages of gestation were fixed, processed for light and transmission electron microscopy, histochemistry and immunohistochemistry. Haemophagous areas were present in placentomes collected between 4 and 10 months of pregnancy. Perl’s reaction for ferric iron was negative in placentomes, but positive in endometrial glands. Positive staining for UF indicated areas in which it was being taken up by phagocytosis and/or fluid phase pinocytosis in areolae of the interplacentomal mesenchyme, with little staining in endometrial stroma. Imunohistochemistry detected UF in trophectoderm of haemophagous regions of placentomes and in other parts of the foetal villous tree, but the strongest immunostaining was in the epithelial cells and lumen of uterine glands. Ultrastructural analyses indicated that erythrophagocytosis was occurring and that erythrocytes were present inside cells of the chorion that also contained endocytic vesicles and caveolae. Results of this study indicate that both the haemophagous areas of placentomes and the areolae at the interface between chorion and endometrial glands are important sites for iron transfer from mother to foetal‐placental tissues in buffalo throughout pregnancy. 相似文献
12.
Willows (Salix spp.) are beneficial as a potential source of renewable energy, riparian barriers and riverbank control, yet are considered
invasive weeds when they clog watercourses and lead to erosion and flooding. Interactions between willow rustMelampsora epitea (Thüm.) (Uredinales: Melampsoraceae) and leaf beetlePhratora spp. (Coleoptera: Chrysomelidae) feeding damage have an impact on effective pest management and biological control. The present
study investigated the effects of(a) prior mechanical leaf damage on rust development, and(b) rust infection on beetle feeding under laboratory conditions for different time intervals and levels of damage. Willow rust
infection significantly reduced the amount of leaf area consumed by beetles. The result was similar when a compatible or an
incompatible rust pathotype was sprayed ontoSalix viminalis (L.) ‘Mullatin’ plants. There were no overall significant effects of mechanical damage on rust development, although the
lowest level of rust infection was found with the incremental damage treatment. There were, however, differences of significance
for leaf position and damage status, with damaged leaves at all positions having fewer pustules and a smaller pustule area
than the corresponding undamaged leaves. There was no detectable effect of possible volatile emissions from crushed willow
leaves on rust infection and development, although the volatile compoundcis-3-hexenyl acetate significantly reduced pustule diameter and overall pustule area. The results are discussed in terms of
the implications for pest management and biological control.
Corresponding author
http://www.phytoparasitica.org posting April 6, 2003. 相似文献
13.
Cudworth DP Hegde VB Yap MC Guenthenspberger KA Hamilton CT Pechacek JT Johnson PL Bis SJ Tisdell FE Dripps JE Bruce TJ Dintenfass LP Gifford JM Karr LL Kempe MK McCormick DC Schoonover JR 《Journal of agricultural and food chemistry》2007,55(18):7517-7526
An extended lipophilic system that incorporated some key elements of first-generation 2,6-dihaloaryl actives, such as 1, demonstrated desirable efficacy against chewing insects as well as sap-feeding insects. These four-ring systems, based on 2, were accessed primarily via Suzuki couplings of halothiophene derivatives with appropriately substituted boronic acids. In particular, phenylthiophene systems that incorporated haloxyether groups, such as those in 3, 4, and 5, had the broadest spectrum of activity across chewing and sap-feeding insect pests. Expansion of this structure-activity relationship to include compounds with differing substitution patterns on the thiophene-C-ring and aryl-D-rings was undertaken. The synthesis and insecticidal activity of 3-aryl-5-(thiophen-2-yl)-1-methyl-1H-[1,2,4]triazoles will be described. 相似文献
14.
Meteorological analyses of precipitation and air quality data for the period 1976 to 1983 have been undertaken to infer potential source regions of acidity in Ontario. Techniques such as air parcel trajectory modelling and synoptic weather classification have been utilized. A meteorological data acquisition system has been implemented to provide historical and real-time trajectory statistics. This paper provides an overview of these studies. For areas of South and Central Ontario, precipitation events most commonly occur with pre-warm front and cyclonic situations, and trajectories from the south and southwest octants. Furthermore, most of the reported wet deposition of S and N is associated with trajectories from these octants, the direction of the Ohio Valley industrial source region and industrialized SW Ontario. High air concentrations of S and N are also associated with trajectories from these octants. 相似文献
15.
Dryobalanops aromatica Gaertn. f. is a major tropical canopy species in lowland tropical rain forests in Peninsular Malaysia. Diurnal changes in net photosynthetic rate (A) and stomatal conductance to water vapor (g(s)) were measured in fully expanded young and old leaves in the uppermost canopy (35 m above ground). Maximum A was 12 and 10 micro mol m(-2) s(-1) in young and old leaves, respectively; however, because of large variation in A among leaves, mean maximum A in young and old leaves was only 6.6 and 5.5 micro mol m(-2) s(-1), respectively. Both g(s) and A declined in young leaves when T(leaf) exceeded 34 degrees C and leaf-to-air vapor pressure deficit (DeltaW) exceeded 0.025, whereas in old leaves, g(s) and A did not start to decline until T(leaf) and DeltaW exceeded 36 degrees C and 0.035, respectively. Under saturating light conditions, A was linearly related to g(s). The coefficient of variation (CV) for the difference between the CO(2) concentrations of ambient air and the leaf intercellular air space (C(a) - C(i)) was smaller than the CV for A or g(s), suggesting that maximum g(s) was mainly controlled by mesophyll assimilation (A/C(i)). Minimum C(i)/C(a) ratios were relatively high (0.72-0.73), indicating a small drought-induced stomatal limitation to A and non-conservative water use in the uppermost canopy leaves. 相似文献
16.
A new method for assessing coastal environments using the reproduction potential of corals has been developed and examined
in situ. Six assessment racks were deployed before the full moon of May 2006 at three sites located around a river outlet
in Nagura Bay, Ishigaki Is. and at one control location in Sekisei Lagoon. Each rack was equipped with two marine blocks (MB)
containing 378 holes, two cases of coral settlement devices (CSDs), each containing 120 CSDs, and a water temperature logger.
Assessment was based on recruitment of Acropora due to mass spawning. After 4 months of deployment, the surface of assessment racks showed apparent biofouling depending
on sites mainly by algal settlement on the surfaces. Almost all the holes of the MBs were partly occupied, mainly by turf
algae. Nagura Bay was thought likely to be an “unhealthy” coral reef due to runoff from land. However, our assessment showed
that there were 0.85 corals per CSD in the Bay, compared with 0.51 in Sekisei Lagoon, indicating that coral larvae supply
is not the cause of the unhealthy condition of corals in the Nagura Bay. 相似文献
17.
DE Boerner RD Kurtz JA Craven GM Ross FW Jones WJ Davis 《Science (New York, N.Y.)》1999,283(5402):668-670
The subcrustal lithosphere underlying the southern Archean Churchill Province (ACP) in western Canada is at least one order of magnitude more electrically conductive than the lithosphere beneath adjacent Paleoproterozoic crust. The measured electrical properties of the lithosphere underlying most of the Paleoproterozoic crust can be explained by the conductivity of olivine. Mantle xenolith and geological mapping evidence indicate that the lithosphere beneath the southern ACP was substantially modified as a result of being trapped between two nearly synchronous Paleoproterozoic subduction zones. Tectonically induced metasomatism thus may have enhanced the subcrustal lithosphere conductivity of the southern ACP. 相似文献
18.
Antisense transcription in the mammalian transcriptome 总被引:2,自引:0,他引:2
Katayama S Tomaru Y Kasukawa T Waki K Nakanishi M Nakamura M Nishida H Yap CC Suzuki M Kawai J Suzuki H Carninci P Hayashizaki Y Wells C Frith M Ravasi T Pang KC Hallinan J Mattick J Hume DA Lipovich L Batalov S Engström PG Mizuno Y Faghihi MA Sandelin A Chalk AM Mottagui-Tabar S Liang Z Lenhard B Wahlestedt C;RIKEN Genome Exploration Research Group;Genome Science Group 《Science (New York, N.Y.)》2005,309(5740):1564-1566
19.
Schaeffer EM Debnath J Yap G McVicar D Liao XC Littman DR Sher A Varmus HE Lenardo MJ Schwartzberg PL 《Science (New York, N.Y.)》1999,284(5414):638-641
T cell receptor (TCR) signaling requires activation of Zap-70 and Src family tyrosine kinases, but requirements for other tyrosine kinases are less clear. Combined deletion in mice of two Tec kinases, Rlk and Itk, caused marked defects in TCR responses including proliferation, cytokine production, and apoptosis in vitro and adaptive immune responses to Toxoplasma gondii in vivo. Molecular events immediately downstream from the TCR were intact in rlk-/-itk-/- cells, but intermediate events including inositol trisphosphate production, calcium mobilization, and mitogen-activated protein kinase activation were impaired, establishing Tec kinases as critical regulators of TCR signaling required for phospholipase C-gamma activation. 相似文献
20.
An assessment of the different soft tissues (STs) of Pernaviridis as biomonitoring agents of Pb has not been specifically reported in the literature. Based on the results of our laboratory studies,different rates of accumulation and depuration of Pb in the different STs werefound and this might be due to different mechanisms of metal binding andregulation. At the end of depuration, Pb levels in the different STs of P. viridis were 3–100 times higher than those before Pb exposure. The high ratio of maximum to minimum Pb levels (160) and the similar patterns (althoughdifferent rates) of accumulation and depuration in the different STs forPb indicated that P. viridis is a good biomonitoring organism for Pband our conclusion is also supported by analysis of field samples collected fromcontaminated and uncontaminated sites. The distribution of Pb in the STssuggests that gills and byssus are better for the biomonitoring of Pb than the total ST. 相似文献