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1.
Dopamine and adrenaline injected into mice produce dose-related mydriasis. The effects of both dopamine and adrenaline are antagonized similarly by the alpha-adrenergic blocking agents, phentolamine and thymoxamine, as well as by haloperidol, but are not prevented by pretreatment with reserpine. These results suggest that in mice dopamine produces mydriasis by direct stimulation of alpha-adrenergic receptors in the dilator iridis. 相似文献
2.
The exquisite immunological specificity of cytotoxic T lymphocytes-target cell (CTL-TC) conjugation and lysis is overridden in the presence of certain plant lectins. The role of concanavalin A (Con A) in lectin-dependent, CTL-mediated cytolysis (LDCC) has been investigated. Papain-treated TC are refractory to LDCC, but regain susceptibility following a 3-hr incubation without the enzyme. Papain-treated TC allowed to recover in the presence of tunicamycin (TM; an inhibitor of N-linked glycosylation), are totally refractory to LDCC. Refractoriness of TM-treated TC to LDCC is not due to an overall resistance to lysis or to lack of Con A binding, as these cells can be lysed by specifically sensitized CTL or by H-2 antibody and complement and display a sufficiently high Con A-binding capacity, indistinguishable from intact TC, probably through O-linked, cell-surface glycosyl residues. The finding that TC (TM-treated) capable of binding normal Con A quantities cannot, however, engage in lectin-dependent CTL-TC conjugation and lysis indicates that Con A must react selectively with a specific TC-surface component(s), thereby rendering the TC recognizable by effector CTL, rather than by simply bridging ("glueing") CTL and TC. Affinity absorption and elution from Sepharose-Con A beads as well as specific immunoprecipitations by antibodies against cell surface determinants, have shown effective Con A binding to TC surface components of molecular weights corresponding to 45-kDa product of the H-2K and D MHC genes and, possibly, to a 30-kDa component. Antibodies against MHC proteins but not against non-MHC surface proteins of the TC have produced effective inhibition of LDCC. This and previous investigations show that in nonspecific LDCC as in specific CTL-mediated lysis, TC-MHC determinants are involved in signaling TC recognition and lysis. 相似文献
3.
大鼠食管胸段和腹段壁内乙酰胆碱酯酶(AChE)阳性神经存在于神经束和分支的粗细神经纤维内,也见于外膜丛,肌间丛,粘膜下丛和粘膜肌内。食管肌层内AChE阳性神经纤维多而密集,而食管腹段肌内尤为丰富,肌间神经纤维末梢分布于肌束表面,可能与控制肌纤维活动有关;分布于肌内,粘膜下层和上皮基部的AChE阳性神经中,尚含有内脏感觉神经纤维。食管壁的肌间丛和粘膜下丛内散在有多极形和卵园形的AChE阳性神经元,在食管腹段内数多,而以中小型神经元为主。 相似文献
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Galina Feinberg-Gorenshtein Avital Guedj Keren Shichrur Marta Jeison Drorit Luria Yona Kodman Shifra Ash Meora Feinmesser Liat Edry Noam Shomron Abraham Weizman Isaac Yaniv Smadar Avigad 《PloS one》2013,8(11)
Neuroblastoma (NB) arises from the embryonic neural crest and is the most common extracranial solid tumor in children under 5 years of age. Reduced expression of Dicer1 has recently been shown to be in correlation with poor prognosis in NB patients. This study aimed to investigate the mechanisms that could lead to the down-regulation of Dicer1 in neuroblastoma. We used computational prediction to identify potential miRs down-regulating Dicer1 in neuroblastoma. One of the miRs that were predicted to target Dicer1 was miR-192. We measured the levels of miR-192 in 43 primary tumors using real time PCR. Following the silencing of miR-192, the levels of dicer1 cell viability, cell proliferation and migration capability were analyzed. Multivariate analysis identified miR-192 as an independent prognostic marker for relapse in neuroblastoma patients (p=0.04). We were able to show through a dual luciferase assay and side-directed mutational analysis that miR-192 directly binds the 3'' UTR of Dicer1 on positions 1232-1238 and 2282-2288. An increase in cell viability, proliferation and migration rates were evident in NB cells transfected with miR-192-mimic. Yet, there was a significant decrease in proliferation when NB cells were transfected with an miR-192-inhibitor We suggest that miR-192 might be a key player in NB by regulating Dicer1 expression. 相似文献
6.
Bovine ephemeral fever (BEF) is an economically important viral vector-borne cattle disease. Several live-attenuated, inactivated and recombinant vaccines have been tested, demonstrating varying efficacy. However, to the best of our knowledge, duration of immunity conferred by an inactivated vaccine has never been reported. In the last decade, Israel has faced an increasing number of BEF outbreaks. The need for an effective vaccine compatible with strains circulating in the Middle East region led to the development of a MONTANIDE™ ISA 206 VG (water-in-oil-in-water), inactivated vaccine based on a local strain. We tested the safety, immunogenicity and duration of immunity conferred by this vaccine. The induced neutralizing antibody (NA) response was followed for 493 days in 40 cows vaccinated by different protocols. The vaccine did not cause adverse reactions or a decrease in milk production. All cows [except 2 (6.7%) which did not respond to vaccination] showed a significant rise in NA titer of up to 1:256 following the second, third or fourth booster vaccination. Neutralizing antibody levels declined gradually to 1:16 up to 120 days post vaccination. This decline continued in cows vaccinated only twice, whereas cows vaccinated 3 or 4 times showed stable titers of approximately 1:16 for up to 267 days post vaccination. At least three vaccinations with the inactivated BEF vaccine were needed to confer long-lasting immunity. These results may have significant implications for the choice of vaccination protocol with inactivated BEF vaccines. Complementary challenge data should however be added to the above results in order to determine what is the minimal NA response conferring protection from clinical disease. 相似文献
7.
Leeat Keren Ora Zackay Maya Lotan‐Pompan Uri Barenholz Erez Dekel Vered Sasson Guy Aidelberg Anat Bren Danny Zeevi Adina Weinberger Uri Alon Ron Milo Eran Segal 《Molecular systems biology》2013,9(1)
Most genes change expression levels across conditions, but it is unclear which of these changes represents specific regulation and what determines their quantitative degree. Here, we accurately measured activities of ~900 S. cerevisiae and ~1800 E. coli promoters using fluorescent reporters. We show that in both organisms 60–90% of promoters change their expression between conditions by a constant global scaling factor that depends only on the conditions and not on the promoter's identity. Quantifying such global effects allows precise characterization of specific regulation—promoters deviating from the global scale line. These are organized into few functionally related groups that also adhere to scale lines and preserve their relative activities across conditions. Thus, only several scaling factors suffice to accurately describe genome‐wide expression profiles across conditions. We present a parameter‐free passive resource allocation model that quantitatively accounts for the global scaling factors. It suggests that many changes in expression across conditions result from global effects and not specific regulation, and provides means for quantitative interpretation of expression profiles. 相似文献
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9.
Photosynthesis Research - The acclimation of cyanobacterial photosynthetic apparatus to iron deficiency is crucial for their performance under limiting conditions. In many cyanobacterial species,... 相似文献
10.
Remodeling of the actin cytoskeleton during mammalian sperm capacitation and acrosome reaction 总被引:7,自引:0,他引:7
Brener E Rubinstein S Cohen G Shternall K Rivlin J Breitbart H 《Biology of reproduction》2003,68(3):837-845
The sperm acrosome reaction and penetration of the egg follow zona pellucida binding only if the sperm has previously undergone the poorly understood maturation process known as capacitation. We demonstrate here that in vitro capacitation of bull, ram, mouse, and human sperm was accompanied by a time-dependent increase in actin polymerization. Induction of the acrosome reaction in capacitated cells initiated fast F-actin breakdown. Incubation of sperm in media lacking BSA or methyl-beta-cyclodextrin, Ca(2+), or NaHCO(3), components that are all required for capacitation, prevented actin polymerization as well as capacitation, as assessed by the ability of the cells to undergo the acrosome reaction. Inhibition of F-actin formation by cytochalasin D blocked sperm capacitation and reduced the in vitro fertilization rate of metaphase II-arrested mouse eggs. It has been suggested that protein tyrosine phosphorylation may represent an important regulatory pathway that is associated with sperm capacitation. We show here that factors known to stimulate sperm protein tyrosine phosphorylation (i.e., NaHCO(3), cAMP, epidermal growth factor, H(2)O(2), and sodium vanadate) were able to enhance actin polymerization, whereas inhibition of tyrosine kinases prevented F-actin formation. These data suggest that actin polymerization may represent an important regulatory pathway in with sperm capacitation, whereas F-actin breakdown occurs before the acrosome reaction. 相似文献