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1.
We released seeds of two sympatric tree species, Corylus mandshurica (seed with thinner seed hull, higher nutrition) and C. heterophylla (seeds with thicker seed hull, lower nutrition) in the masting year of C. mandshurica in 2008, and C. heterophylla in 2009, respectively, to investigate how seed masting of the two sympatric Corylus species affects seed removal and dispersal fitness of the two species differently at both intra- and inter-specific levels.
At intra-specific level, the authors found mast seeding of both C. mandshurica and C. heterophylla significantly reduced seed removal, seed consumption, but increased seed dispersal distance and seed dispersal fitness of
the released seeds. Mast seeding of C. mandshurica increased seed caching of C. mandshurica. At inter-specific level, the authors found mast seeding of C. mandshurica reduced seed removal of C. heterophylla, but mast seeding of C. heterophylla did not significantly reduce seed removal of C. mandshurica. Mast seeding of C. mandshurica reduced seed consumption of C. heterophylla, while mast seeding of C. heterophylla reduced seed consumption of C. mandshurica. We found mast seeding of C. mandshurica significantly reduced seed dispersal distance of C. heterophylla, while mast seeding of C. heterophylla significantly increased seed dispersal distance of C. mandshurica. We found that mast seeding of C. mandshurica significantly increased seed dispersal fitness of C. heterophylla, while mast seeding of C. heterophylla did not significantly increase seed dispersal fitness of C. mandshurica. More studies are needed to reveal the ecological consequences of mast seeding at inter-specific or community-level. Seed
traits may attribute the differences of mast seeding at inter-specific level. Because seeds with thinner seed hull and higher
nutrition were more harvested and eaten by rodents, mast seeding of C. mandshurica might have reduced seed removal and seed consumption, but increased dispersal fitness of C. heterophylla (seeds with thicker seed hull, lower nutrition). Therefore, synchrony among species is, or is not, selectively beneficial
to the focus species depends on seed traits which determine gains from mast seeding at inter-specific level. 相似文献
2.
Yi Ting Zhou Li Li Chew Sheng-cai Lin Boon Chuan Low 《Molecular biology of the cell》2010,21(18):3232-3246
The BNIP-2 and Cdc42GAP homology (BCH) domain is a novel regulator for Rho GTPases, but its impact on p50-Rho GTPase-activating protein (p50RhoGAP or Cdc42GAP) in cells remains elusive. Here we show that deletion of the BCH domain from p50RhoGAP enhanced its GAP activity and caused drastic cell rounding. Introducing constitutively active RhoA or inactivating GAP domain blocked such effect, whereas replacing the BCH domain with endosome-targeting SNX3 excluded requirement of endosomal localization in regulating the GAP activity. Substitution with homologous BCH domain from Schizosaccharomyces pombe, which does not bind mammalian RhoA, also led to complete loss of suppression. Interestingly, the p50RhoGAP BCH domain only targeted RhoA, but not Cdc42 or Rac1, and it was unable to distinguish between GDP and the GTP-bound form of RhoA. Further mutagenesis revealed a RhoA-binding motif (residues 85-120), which when deleted, significantly reduced BCH inhibition on GAP-mediated cell rounding, whereas its full suppression also required an intramolecular interaction motif (residues 169-197). Therefore, BCH domain serves as a local modulator in cis to sequester RhoA from inactivation by the adjacent GAP domain, adding to a new paradigm for regulating p50RhoGAP signaling. 相似文献
3.
Tissue plasminogen activator (tPA) has been implicated in neurite outgrowth and neurological recovery post stroke. tPA converts the zymogen plasminogen (Plg) into plasmin. In this study, using plasminogen knockout (Plg-/-) mice and their Plg-native littermates (Plg+/+), we investigated the role of Plg in axonal remodeling and neurological recovery after stroke. Plg+/+ and Plg-/- mice (n = 10/group) were subjected to permanent intraluminal monofilament middle cerebral artery occlusion (MCAo). A foot-fault test and a single pellet reaching test were performed prior to and on day 3 after stroke, and weekly thereafter to monitor functional deficit and recovery. Biotinylated dextran amine (BDA) was injected into the left motor cortex to anterogradely label the corticospinal tract (CST). Animals were euthanized 4 weeks after stroke. Neurite outgrowth was also measured in primary cultured cortical neurons harvested from Plg+/+ and Plg-/- embryos. In Plg+/+ mice, the motor functional deficiency after stroke progressively recovered with time. In contrast, recovery in Plg-/- mice was significantly impaired compared to Plg+/+ mice (p<0.01). BDA-positive axonal density of the CST originating from the contralesional cortex in the denervated side of the cervical gray matter was significantly reduced in Plg-/- mice compared with Plg+/+ mice (p<0.05). The behavioral outcome was highly correlated with the midline-crossing CST axonal density (R2>0.82, p<0.01). Plg-/- neurons exhibited significantly reduced neurite outgrowth. Our data suggest that plasminogen-dependent proteolysis has a beneficial effect during neurological recovery after stroke, at least in part, by promoting axonal remodeling in the denervated spinal cord. 相似文献
4.
Hematopoietic cell phosphatase (Hcph) was identified by amplification of conserved protein tyrosine phosphatase sequences from a myeloid cell line and is predominantly expressed in hematopoietic cells. Hcph is unique in containing two, tandemly repeated, src-homology 2 domains in the amino terminal region of the phosphatase. Using a genomic probe in interspecific backcross analysis, the murine Hcph gene maps to mouse Chromosome 6 and is tightly linked to the Tnfr-2 and Ly-4 genes. 相似文献
5.
6.
M R Yi M H Shin M H Leem J S Ryu M H Ahn D Y Min 《The Korean journal of parasitology》1990,28(1):25-30
The direct wet mount examination of vaginal secretion, widely applied for the diagnosis of Trichomonas vaginalis infection in woman patients, is rapid and economical, however, the sensitivity of this technique is not so high. In this study enzyme-linked immunosorbent assay (ELISA) was employed for the detection of serum anti-T. vaginalis IgG and IgM antibodies from 30 vaginal trichomoniasis patients and 30 non-infected healthy persons. The results were as follows: 1. Serum ELISA-IgG value was 0.37 +/- 0.134 (Mean +/- S.D.) in vaginal trichomoniasis patients and 0.21 +/- 0.054 in healthy controls (p less than 0.005), and the sensitivity and specificity of ELISA for serum IgG antibody were 70.0% and 96.7%, respectively. 2. Serum ELISA-IgM value was 0.33 +/- 0.177 (Mean +/- S.D.) in vaginal trichomoniasis patients and 0.11 +/- 0.051 in healthy controls (p less than 0.005), and the sensitivity and specificity of ELISA for serum IgM antibody were 70.0% and 96.7%, respectively. 3. The ELISA-IgG values showed a significant correlation with ELISA-IgM values (r = 0.77, p less than 0.005). With above results, it is assumed that ELISA is a reliable method for the diagnosis of T. vaginalis infection and simultaneous measurement of serum IgG and IgM with this technique is recommended. 相似文献
7.
A simple and effective procedure for the construction of linear restriction fragment maps was developed. Using a two-enzyme digestion, two-dimensional (2-D) electrophoresis procedure, all the restriction fragments in a 50- to 100-kb DNA can be individually resolved and displayed on a 2-D plane. This 2-D gel pattern, with appropriate markers, provides a fixed set of x, y coordinates for each fragment obtained from the single and double digestion as well as the relationship between the two steps. A matrix is constructed from the 2-D pattern. The vertical column shows all the singly digested individual fragments and their sizes obtained from each restriction enzyme treatment, and the dividing horizontal row shows all the doubly digested DNA fragments and their sizes after treatment with two enzymes. The order of arrangement is always from the smallest to the largest fragments. Using this matrix, two linear DNA restriction maps for these two enzymes can be simultaneously constructed in a self-reconfirming manner. As examples for this procedure, we describe the construction of two linear restriction fragment maps, a combination of EcoRI and BamHI digestion as well as a combination of EcoRI and HindIII digestion of lambda-phage DNA. 相似文献
8.
本文论证了菲波纳斯(Fibonacci)级数与菊花花冠结构的关系,发现了花冠的通用数学模式:花冠(数目)=(5×倍数)十F_n(F_(n-1)+F_(n-2)) 相似文献
9.
武陵山地区鱼类寄生杆咽属线虫两新种 总被引:1,自引:0,他引:1
本文报道在武陵山地区的白甲鱼[(Varicorkinus(Onychostoma)simus(SauvageetDabry)]和沪溪直口峻(RectorisluxiensisWuetYao)中发现的两种杆咽属(Rhabdochona)线虫新种,定名为白甲鱼杆咽线虫,新种(RhabdOchonaonyrkostomisp.nov.)和短咽杆咽线虫,新种(RhabdOchonabrevichonasp.nov.),并对两新种进行了测量和详细的描述。 相似文献
10.
Shukuro Araki Shigehiro Yi Tatsufumi Murakami Susumu Watanabe Shinichi Ikegawa Kiyoshi Takahashi Ken-ichi Yamarnura 《Molecular neurobiology》1994,8(1):15-23
To analyze the pathologic processes of amyloid deposition in type I familial amyloidotic polyneuropathy (FAP), mice were made
transgenic by introducing the human mutant transthyretin (TTR) gene(MT-hMet 30). An inbred strain of mouse, C57 BL/6, was
chosen. Transgenic mice were killed using ether anesthesia at 3-mo intervals up to 24 mo after birth. In these transgenic
mice, amyloid deposition started in the gastrointestinal tract, cardiovascular system, and kidneys and extended to various
other organs and tissues with advancing age. The pattern of amyloid deposition was similar to that observed in human autopsy
cases of FAP, except for its absence in the choroid plexus and in the peripheral and autonomic nervous systems.
We extracted the amyloid fibrils from kidneys of these mice with a human mutant TTR gene and analyzed them immunochemically
and electronmicroscopically. Deposited amyloid was shown to be composed of human mutant TTR and mouse serum amyloid P component.
Amyloid fibril from transgenic mice was morphologically and immunohistochemically similar to that of human FAP.
The most striking pathologic feature of the transgenic mice was the absence of amyloid deposition in the peripheral and autonomic
nervous tissues. Thus, other intrinsic factors may be involved in amyloid deposition in the nervous tissues of human FAP. 相似文献