Membrane channel connexin (Cx) forms gap junctions that are implicated in the homeostatic regulation of multicellular systems;
thus, hematopoietic cells were assumed not to express Cxs. However, hematopoietic progenitors organize a multicellular system
during the primitive stage; thus, the aim of the present study was to determine whether Cx32, a member of the Cx family, may
function during the primitive steady-state hematopoiesis in the bone marrow (BM). First, the numbers of mononuclear cells
in the peripheral blood and various hematopoietic progenitor compartments in the BM decreased in Cx32-knockout (KO) mice.
Second, on the contrary, the number of primitive hematopoietic progenitor cells, specifically the Lin−/c-kit+/Scal+ fraction, the KSL progenitor cell compartment, also increased in Cx32-KO mice. Third, expression of Cx32 was detected in Lin−/c-kit+ hematopoietic progenitor cells of wild-type mice (0.27% in the BM), whereas it was not detected in unfractionated wild-type
BM cells. Furthermore, cell-cycle analysis of the fractionated KSL compartment from Cx32-KO BM showed a higher ratio in the
G2/M fraction. Taken together, all these results imply that Cx32 is expressed solely in the primitive stem cell compartment,
which maintains the stemness of the cells, i.e., being quiescent and noncycling; and once Cx32 is knocked out, these progenitor
cells are expected to enter the cell cycle, followed by proliferation and differentiation for maintaining the number of peripheral
blood cells. 相似文献
Harnessing the regenerative potential of the central nervous system to repopulate depleted cellular populations from endogenous stem cells would be a novel approach for the treatment of neurological diseases resulting from cell death. Consequently, understanding if and how the central nervous system is capable of such regeneration would determine if such an approach is feasible. In this report, we provide evidence of widespread regenerative response in the spinal cord of amyotrophic lateral sclerosis transgenic mice. However, this regenerative response appears to be largely unproductive. We demonstrate that there is significantly increased gliogenesis, but an absence of convincing neurogenesis. The fact that the neurodegenerative process stimulates a regenerative response suggests that the adult spinal cord has at least limited ability for regeneration. Further studies will determine if this endogenous regenerative process can be enhanced and directed so as to slow or even reverse the natural progression of this devastating disease. 相似文献
The chemical constituents of Symplocos genus were reviewed with 90 structures and 28 references cited. These constituents include triterpenoids, flavonoids, lignans, phenols, steroids, alkaloids, and iridoids. Triterpenoids are the dominant constituents within the genus Symplocos, some of them exhibited antiproliferative effects. Some phenolic glycoside derivatives showed inhibitory activity against snake-venom phosphodiesterase I and human nucleotide pyrophosphatase phosphodiesterase. 相似文献
The mitochondrial respiratory complex II, or succinate:ubiquinone oxidoreductase, is an integral membrane protein complex in both the tricarboxylic acid cycle (Krebs cycle) and aerobic respiration. The gene sequences of each complex II subunit were measured by RT-PCR. N-terminal sequencing work was performed to identify the mitochondrial targeting signal peptide of each subunit. Complex II was extracted from porcine heart and purified by the ammonium sulfate precipitation method. The sample was solubilized by 0.5% (w/v) sugar detergent n-decyl-beta-D-maltoside, stabilized by 200 mM sucrose, and crystallized with 5% (w/v) poly(ethylene glycol) 4000. Important factors for the extraction, purification and crystallization of mitochondrial respiratory complex II are discussed. 相似文献
The binding of exogenous DNA to sperm is a key process for sperm-mediated gene transfer; however, the underlying molecular mechanisms have yet to be elucidated. In the present study, we aimed to identify the DNA binding proteins (DBPs) in rabbit sperm and to gain further understanding of the molecular mechanism of sperm and exogenous DNA interaction. Native polyacrylamide gel electrophoresis was used for separating free sperm proteins and complexes of DNA fragment/sperm proteins. A distinct band was found after Coomassie blue staining, and seven potential proteins were identified by mass spectrometry analysis. An analysis of the physical/chemical properties of the seven proteins revealed that the sperm inner acrosomal membrane protein IAM38 (IAM38) matched the features of the DBPs. Western blotting analysis showed that the IAM38 and CD4 were present in the sperm but not in the seminal plasma. Blocking of the IAM38 impaired the DNA-binding capacity of the sperm. Blocking the CD4 decreased the DNA-uptake capacity of the sperm but did not influence the DNA-binding capacity of the sperm. Moreover, the EGFP-positive embryos and EGFP-positive blastocysts were also decreased after IAM38 blocking or CD4 blocking in comparison with the control group. In conclusion, our results imply that foreign DNA first binds to the transmembrane IAM38 of the sperm plasma membrane and then forms the complex of DNA/IAM38/CD4 with CD4 to complete the transportation of exogenous DNA into the nucleus of sperm.
Biochemical Genetics - The Cashmere goat (Capra hircus) is renowned for its high-quality fiber production trait. The hair cycle in Cashmere goat has an annual rhythm. To deepen the understanding of... 相似文献
Chiral resolution of binaphthylamine is often a toilful conundrum in the field of analytical chemistry and biomedicine. The work puts forward a selective, sensitive, and miniaturized analytical method based on molecularly imprinted polymers (MIPs) as adsorbent for miniaturized tip solid-phase extraction (MTSPE) in the separation of binaphthylamine enantiomer. This method combines the advantages of MIPs (high selectivity), MTSPE (low consumption), and high-performance liquid chromatography (HPLC, high sensitivity). A simple synthesis methodology of MIP (P2) was conducted through bulk polymerization with (S)-(?)-1,1′-binaphthyl-2,2′-diamine (S-DABN) as template together with methacrylic acid monomer, and ethylene glycol dimethacrylate as cross-linker in proper porogen, realizing a selective recognition and efficient enrichment for S-DABN. The method exhibited appreciable linearity (0.06–1.00 mg ml?1), low quantification limit (0.056 mg ml?1), good absolute recoveries (45.70%–69.29%), and high precision (relative standard deviations ≤ 3.54%), along with low consumption (0.50 ml sample solution and 25.0 mg adsorbent). Based on the density functional theory, computational simulation was used to make a preliminary prediction for rational design of MIPs and gave a reasonable elaboration involving the potential mechanism of templates interacting with functional monomers. The adsorption kinetics and thermodynamics were investigated to evaluate the recombination process of substrates. In addition, the selectivity of MIPs for S-DABN was obtained by MIP-MTSPE coupled with HPLC, which supports the feasibility of this convenient design process. The proposed method was employed for selective extraction of S-DABN and exhibited promising potential in the application of chiral analysis. 相似文献
In Vitro Cellular & Developmental Biology - Plant - Blueberry (Vaccinium corymbosum L.) is an important horticultural crop with many nutraceutical values. With increasing market demand,... 相似文献