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61.
New findings reveal that, in Caenorhabditis elegans embryos, the centrosome provides signals that induce cell polarization, independently of its function as the microtubule-organizing center. 相似文献
62.
A statistical approach was used to characterize the heterogeneous structures of bacterial cellulose samples pretreated with four kinds of ionic liquids (ILs). The structural heterogeneity of these samples was measured by Fourier transform infrared spectroscopy as well as solid-state NMR methods such as cross-polarization magic-angle spinning and dipolar-assisted rotational resonance. The obtained data matrices were then evaluated by principal components analysis. The measured 1-D data clearly revealed the modification of crystalline cellulose; in addition, the statistical approach revealed subtle structural changes that occurred upon pretreatment with different kinds of ILs. To investigate whether such regenerated structural changes occurred because of solubilization, we examined the intermolecular nuclear Overhauser effect between cellulose and an IL. Our results clarify how the nucleophilic imidazole is attacked and suggest that the cation of the IL is associated with the collapse of hydrogen bonds in cellulose. 相似文献
63.
Tanigawa M Miyamoto K Kobayashi S Sato M Akutsu H Okabe M Mekada E Sakakibara K Miyado M Umezawa A Miyado K 《Molecular reproduction and development》2008,75(1):150-155
Tetraspanin CD81 is closely homologous in amino acid sequence with CD9. CD9 is well known to be involved in sperm-egg fusion, and CD81 has also been reported to be involved in membrane fusion events. However, the function of CD81 as well as that of CD9 in membrane fusion remains unclear. Here, we report that disruption of the mouse CD81 gene led to a reduction in the fecundity of female mice, and CD81-/- eggs had impaired ability to fuse with sperm. Furthermore, we demonstrated that when CD81-/- eggs were incubated with sperm, some of the sperm that penetrated into the perivitelline space of CD81-/- eggs had not yet undergone the acrosome reaction, indicating that the impaired fusibility of CD81-/- eggs may be in part caused by failure of the acrosome reaction of sperm. In addition, we showed that CD81 was highly expressed in granulosa cells, somatic cells that surround oocytes. Our observations suggest that there is an interaction between sperm and CD81 on somatic cells surrounding eggs before the direct interaction of sperm and eggs. Our results may provide new clues for clarifying the cellular mechanism of the acrosome reaction, which is required for sperm-egg fusion. 相似文献
64.
Eisuke Kato Michitsugu Yama Ryo Nakagomi Toshiro Shibata Keizo Hosokawa Jun Kawabata 《Bioorganic & medicinal chemistry letters》2012,22(20):6410-6412
Filipendula kamtschatica is a plant utilized as a traditional medicine by Ainu people in Japan, but its chemical constituents are not much studied. Pancreatic lipase inhibitors are a promising tool for the treatment of obesity. We searched for natural lipase inhibitors from F. kamtschatica and two new compounds were isolated along with the known flavonoid glycoside. The structure elucidation of new compounds revealed these two to be 2-O-caffeoyl-4-O-galloyl-l-threonic acid and 3-O-caffeoyl-4-O-galloyl-l-threonic acid, which can be recognized as a pancreatic lipase’s substrate-like structure. The isolated compounds all showed an inhibitory activity against porcine pancreatic lipase and one of the isomer, 3-O-caffeoyl-4-O-galloyl-l-threonic acid, possessed the most potent activity with IC50 value showing an order lower value compared to others. The substrate-like structure of the new compounds seemed to be important for their activity. 相似文献
65.
We isolated five polymorphic microsatellite loci from the drepanosiphid aphid Tuberculatus quercicola (Matsumura) that is associated with the Daimyo oak, Quercus dentata Thunberg, using the magnetic particles method. The isolated loci were polymorphic, with four to 16 alleles in 40 aphids. Expected heterozygosities ranged from 0.4 to 0.82. These loci can be used to quantify seasonal changes in clonal diversity in the metapopulation and the extent of clonal mixing in the colonies. 相似文献
66.
Kei Yabuki Joji Haratake Yojiro Tsuda Eisuke Shiba Hiroshi Harada Kenji Yorita Kazuyoshi Uchihashi Atsuji Matsuyama Keiji Hirata Masanori Hisaoka 《Biological trace element research》2018,185(1):36-47
Lanthanum (La) carbonate (LC) is one of the most potent phosphate binders that prevents the elevation of serum phosphate levels in patients with end-stage renal diseases undergoing dialysis. LC binds strongly to dietary phosphate and forms insoluble complexes that pass through the gastrointestinal tract. La deposition in patients treated with LC is a recently documented finding particularly observed in gastric mucosa. We herein describe the detailed gastric mucosal lesions in 45 LC-treated patients and address the potential underlying pathologic mechanism using oral LC administration in rats. Microscopically, La deposition, as shown by subepithelial collections of plump eosinophilic histiocytes or small foreign body granulomas containing coarse granular or amorphous inclusion bodies, was found in the gastric mucosa of 44 (97.8%) of the 45 dialysis patients in the study cohort, which was most frequently associated with foveolar hyperplasia (37.8%). Using oral administration of rats with 1000 mg/day LC for 2 or more weeks, La deposition was consistently detectable in the gastric mucosa but not in other organs examined. In addition, various histologic alterations such as glandular atrophy, stromal fibrosis, proliferation of mucous neck cells, intestinal metaplasia, squamous cell papilloma, erosion, and ulcer were demonstrated in the rat model. Thus, orally administered LC can induce mucosal injury, designated here as La gastropathy, which may alter the local environment and result in La deposition in the gastric mucosa, thereby potentially inducing abnormal cell proliferation or neoplastic lesions. 相似文献
67.
Sunadome K Yamamoto T Ebisuya M Kondoh K Sehara-Fujisawa A Nishida E 《Developmental cell》2011,20(2):192-205
68.
Maruyama S Izumikawa K Miyashita M Kabeya H Mikami T Yamanouchi H Sasaki E Yoshida H Izumikawa K 《Microbiology and immunology》2004,48(2):103-109
We isolated Bartonella henselae from an inguinal lymph node of a 36-year-old male patient with cat-scratch disease. The patient had many areas of erythema on his body, swelling of the left inguinal lymph nodes with pain and slight fever. The diagnosis was made on the basis of polymerase chain reaction for B. henselae DNA from the lymph node biopsies and blood sample, and isolation of the organism, histology of the lymph node and serology with an indirect immunofluorescent antibody test. We also analyzed the genome profiles for five strains of 90 isolates from the lymph node by pulsed-field gel electrophoresis after Not I endonuclease digestion. We found two different genomic profiles. These results suggest that the patient had been either co-infected or re-infected with two genetically different strains of B. henselae. 相似文献
69.
Crombag HS Bossert JM Koya E Shaham Y 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2008,363(1507):3233-3243
In humans, exposure to environmental contexts previously associated with drug intake often provokes relapse to drug use, but the mechanisms mediating this relapse are unknown. Based on early studies by Bouton & Bolles on context-induced 'renewal' of learned behaviours, we developed a procedure to study context-induced relapse to drug seeking. In this procedure, rats are first trained to self-administer drug in one context. Next, drug-reinforced lever responding is extinguished in a different (non-drug) context. Subsequently, context-induced reinstatement of drug seeking is assessed by re-exposing rats to the drug-associated context. Using variations of this procedure, we and others reported reliable context-induced reinstatement in rats with a history of heroin, cocaine, heroin-cocaine combination, alcohol and nicotine self-administration. Here, we first discuss potential psychological mechanisms of context-induced reinstatement, including excitatory and inhibitory Pavlovian conditioning, and occasion setting. We then summarize results from pharmacological and neuroanatomical studies on the role of several neurotransmitter systems (dopamine, glutamate, serotonin and opioids) and brain areas (ventral tegmental area, accumbens shell, dorsal striatum, basolateral amygdala, prefrontal cortex, dorsal hippocampus and lateral hypothalamus) in context-induced reinstatement. We conclude by discussing the clinical implications of rat studies on context-induced reinstatement of drug seeking. 相似文献
70.
Toshio Takahashi Osamu Koizumi Eisuke Hayakawa Sumiko Minobe Rinako Suetsugu Yoshitaka Kobayakawa Thomas C. G. Bosch Charles N. David Toshitaka Fujisawa 《Development genes and evolution》2009,219(3):119-129
From an evolutionary point of view, Hydra has one of the most primitive nervous systems among metazoans. Two different groups of peptides that affect neuron differentiation
were identified in a systematic screening of peptide signaling molecules in Hydra. Within the first group of peptides, a neuropeptide, Hym-355, was previously shown to positively regulate neuron differentiation.
The second group of peptides encompasses the PW family of peptides that negatively regulate neuron differentiation. In this
study, we identified the gene encoding PW peptide preprohormone. Moreover, we made the antibody that specifically recognizes
LPW. In situ hybridization and immunohistochemical analyses showed that the PW peptides and the gene encoding them were expressed
in ectodermal epithelial cells throughout the body except for the basal disk. The PW peptides are produced by epithelial cells
and are therefore termed “epitheliopeptides.” Together with Hym-355, the PW family peptides mediate communication between
neurons and epithelial cells and thereby maintain a specific density of neurons in Hydra.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Toshio Takahashi, Osamu Koizumi equally contributed to this study. 相似文献