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41.
The dragon lizard <Emphasis Type="Italic">Pogona vitticeps</Emphasis> has ZZ/ZW micro-sex chromosomes 总被引:1,自引:0,他引:1
Tariq?EzazEmail author Alexander?E.?Quinn Ikuo?Miura Stephen?D.?Sarre Arthur?Georges Jennifer?A.?Marshall Graves 《Chromosome research》2005,13(8):763-776
The bearded dragon, Pogona vitticeps (Agamidae: Reptilia) is an agamid lizard endemic to Australia. Like crocodilians and many turtles, temperature-dependent
sex determination (TSD) is common in agamid lizards, although many species have genotypic sex determination (GSD). P. vitticeps is reported to have GSD, but no detectable sex chromosomes. Here we used molecular cytogenetic and differential banding techniques
to reveal sex chromosomes in this species. Comparative genomic hybridization (CGH), GTG- and C-banding identified a highly
heterochromatic microchromosome specific to females, demonstrating female heterogamety (ZZ/ZW) in this species. We isolated
the P. vitticeps W chromosome by microdissection, re-amplified the DNA and used it to paint the W. No unpaired bivalents were detected in
male synaptonemal complexes at meiotic pachytene, confirming male homogamety. We conclude that P. vitticeps has differentiated previously unidentifable W and Z micro-sex chromosomes, the first to be demonstrated in an agamid lizard.
Our finding implies that heterochromatinization of the heterogametic chromosome occurred during sex chromosome differentiation
in this species, as is the case in some lizards and many snakes, as well as in birds and mammals. Many GSD reptiles with cryptic
sex chromosomes may also prove to have micro-sex chromosomes. Reptile microchromosomes, long dismissed as non-functional minutiae
and often omitted from karyotypes, therefore deserve closer scrutiny with new and more sensitive techniques. 相似文献
42.
43.
Akiko Arata H. Onimaru Ikuo Homma 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1998,119(4):399-408
We analysed the modulation of respiratory neurons by adrenaline or noradrenaline (NA) in a newborn rat brainstem-spinal cord
preparation. Adrenaline or NA caused a dose-dependent depression of the respiratory rhythm and induced C4 spinal tonic discharges.
The inhibitory effect of adrenaline (ED50=0.5 μM) on the respiratory rhythm was stronger than NA (ED50=5 μM). The adrenaline respiratory rhythm depression was partially blocked by the α1-antagonist prazosin or by the α2-antagonist yohimbine. The C4 tonic discharge elicited by adrenaline was blocked by the α1-antagonist prazosin. The direct effects of adrenaline on pre-inspiratory (Pre-I) neurons were examined in a synaptic blockade
solution (low Ca), and fifty-six percent of Pre-I neurons were found to continue firing. In low-Ca solution, Pre-I neurons
were excited (n=29 of 39) or depressed (n=5 of 39) by adrenaline, and excited by α1-agonist phenylephrine or depressed by α2-agonist clonidine. These results suggest that the respiratory rhythm depression under intact network conditions is mediated
by some other inhibitory system. The inhibitory effect of adrenaline on the respiratory rhythm was partially blocked by the
GABAA-antagonists bicuculline or picrotoxin, but not by the GABAB-antagonist phaclofen. The present results suggest that: (1) respiratory rhythm generation is more sensitive to adrenaline
than NA through α-adrenergic action of adrenaline; (2) the activity of Pre-I neurons could be directly regulated by excitation
via α1-receptors and inhibition via α2-receptors; and (3) the depression of the respiratory rhythm by adrenaline is partly mediated by GABAAergic neurons.
Received: 8 April 1997 / Accepted: 6 October 1997 相似文献
44.
Quercetin inhibits the invasion and mobility of murine melanoma B16-BL6 cells through inducing apoptosis via decreasing Bcl-2 expression 总被引:5,自引:0,他引:5
Quercetin has been known to have anti-tumor and anti-oxidation activities. In the present study, we have investigated its
in vitro anti-metastatic activity. Quercetin inhibited the invasion and mobility of murine melanoma B16-BL6 cells in a dose-dependent
manner but did not affect their adhesion to either laminin, fibronectin, or type VI collagen. Moreover, quercetin significantly
inhibited the proliferation of B16-BL6 cells only in the case of time incubation longer than 48 h. Quercetin dose-dependently
decreased the cell rates in S and G2–M phases of cell cycle. The effect of quercetin to cause a remarkable apoptosis of B16-BL6
cells was also demonstrated by flow cytometric assay as well as DNA fragmentation with a typical 180-bp ladder band in agarose
electrophoresis and a quantitative analysis. Furthermore, quercetin markedly inhibited the expression of anti-apoptotic protein
Bcl-2 but hardly influenced Bcl-XL. These results suggest that the inhibition of quercetin on invasiveness and migration of B16-BL6 cells are closely associated
with the arrest of cell cycle as well as the induction of apoptosis by decreasing the Bcl-2 expression.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
45.
46.
Cloning of a truncated Babesia equi gene encoding an 82-kilodalton protein and its potential use in an enzyme-linked immunosorbent assay
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Hirata H Ikadai H Yokoyama N Xuan X Fujisaki K Suzuki N Mikami T Igarashi I 《Journal of clinical microbiology》2002,40(4):1470-1474
To isolate Babesia equi genes encoding immunodominant proteins, a cDNA expression library prepared from B. equi mRNA was immunoscreened with B. equi-infected horse serum. Eighteen positive cDNA clones were obtained, and the clone that showed the strongest immunoreactivity, designated Be82, was further characterized. The Be82 gene consisted of 1,953 bp and contained a partial open reading frame lacking the 5'-terminal sequence. As shown by Western blot analyses, immune sera from mice intraperitoneally injected with the Be82 gene product recognized the 82- and 52-kDa proteins of B. equi but not those of Babesia caballi. The glutathione S-transferase fusion protein expressed in Escherichia coli that was purified and used as the antigen in the enzyme-linked immunosorbent assay reacted specifically with B. equi-infected horse sera. These results suggest that the Be82 gene product is a potential diagnostic antigen candidate in the detection of B. equi infection in horses that will be useful both in the performance of epidemiological studies and in the granting of quarantine passes. 相似文献
47.
A new pseudo-peptide of Arg-Gly-Asp (RGD) with inhibitory effect on tumor metastasis and enzymatic degradation of extracellular matrix 总被引:2,自引:0,他引:2
Hideki Fujii Naoyuki Nishikawa Hiroyuki Komazawa Makoto Suzuki Masayoshi Kojima Isamu Itoh Aya Obata Koichi Ayukawa Ichiro Azuma Ikuo Saiki 《Clinical & experimental metastasis》1998,16(1):94-104
A series of pseudo-peptide analogs of the Arg-Gly-Asp (RGD) sequence of fibronectin have been synthe-sized, and their anti-metastatic effects in mice and inhibitory effects on tumor cell invasion in vitro have been examined. The partially modified retro pseudo-peptide of RGD, Rrev-COCH2CO-D (FC-63), was more effective in inhibiting tumor metastasis than the original RGDS peptide. Replacement of the malonyl moiety of FC-63 with a carboxyethylene linkage (Rrev-COCH2CH2-D, FC-303 ) achieved more potent inhibition of lung metastasis of melanoma cells than FC-63. Among the analogs, FC-336, a p-xylylendiamine derivative having two FC-303 moieties, showed the most potent inhibitory effect on experimental lung metastasis produced by i.v. co-injection with B16-BL6 melanoma or colon 26 M3.1 cells in a dose-dependent manner. Multiple administrations of FC-336 after tumor inoculation also showed efficient therapeutic potency against spontaneous lung metastasis of B16-BL6 melanoma in mice. Furthermore, FC-336 effectively inhibited the invasion, migration and adhesion of tumor cells in vitro, but its inhibitory effects were not more than those of RGDS peptide. Zymography analysis revealed that FC-336 inhibited the degradation of gelatin substrate by matrix metalloproteinases (MMPs) produced by tumor cells, while the RGDS peptide did not affect the enzymatic degradation. These findings indicate that the pseudo-peptides of the RGD sequence, possessing the inhibitory property of the degradation by MMPs differently from original RGD-containing peptides, may be advantageous and useful in preventing tumor metastasis. © Rapid Science 1998 相似文献
48.
Kiyoji Kimura Ryuzo Ohno Ichita Amaki Kenichi Hattori Yutaka Hirota Akira Hoshino Michito Ichimaru Munemoto Ito Ikuo Kimura Tadashi Maekawa Toru Masaoka Toru Nakamura Makoto Ogawa Masao Oguro Kazuo Ohta Shigeyuki Osamura Masanori Shimoyama Fumimaro Takaku Yoshiro Uzuka Kazumasa Yamada 《Medical oncology (Northwood, London, England)》1986,3(1):15-24
A phase I study ofN 4-behenoyl-1-β-d-arabinofuranosylcytosine (BHAC) was conducted in 66 patients, 41 with solid tumors and 25 with hematological malignancies. The patients received either a 2-h single intravenous (i.v.) drip infusion (Schedule 1) or consecutive daily 2-h i.v. infusions (Schedule 2). In Schedule 1 the daily dose was initiated with 1.5 mg kg?1 which was escalated up to 7 mg kg?1. Side-effects were mild, and included nausea, vomiting, epilation, and hot flushes. Because of the presence of the solvent vehicle, HCO-60 and in consideration of the mechanism of action of BHAC, the dose escalation was stopped at 7 mg kg?1. In Schedule 2, the daily dose was started with 1.5 mg kg?1 which was escalated up to 8 mg kg?1 and given for 2–16 days. Myelosuppression was found to be dose-limiting toxicity. The maximum tolerated dose (MTD) in patients with non-hematological solid tumors was assumed to be 5 mg kg?1 daily × 5 days. The plasma disappearance curve of BHAC looked biphasic, and when 4 mg kg?1 of BHAC were administered the half-lives of the initial phase (t 1/2α) and the second phase (t 1/2β) were calculated as 0.798 and 5.76 h respectively. In Schedule 2 complete remission was observed in 5 out of 21 patients with acute leukemia, one partial remission in Hodgkin’s disease, and one 1-B response (Karnofsky) in thyroid papillary adenocarcinoma. 相似文献
49.
Yutaka Inoue Yukari Kitani Satoshi Osakabe Yukitoshi Yamamoto Isamu Murata Ikuo Kanamoto 《Nutrients》2021,13(6)
The purpose of this study was to examine how gold kiwifruit pericarp (pericarp is defined as the skin of the fruit) consumption and the timing thereof affect the postprandial blood glucose profile. The study was conducted on twelve healthy volunteers (six men and six women). According to our results, the simultaneous intake of gold kiwifruit with bread and the prior intake of gold kiwifruit evidently suppressed the postprandial blood glucose elevation compared with exclusive bread intake. There was no significant difference in postprandial blood glucose changes between the ingestion of gold kiwifruit pericarp and pulp and that of gold kiwifruit pulp only. The highest postprandial blood glucose elevation was suppressed by 27.6% and the area under the blood glucose elevation curve by 29.3%, even with the exclusive ingestion of gold kiwifruit pulp. We predicted that the ingestion of both the pericarp and pulp of gold kiwifruit would reduce the postprandial blood glucose elevation to a greater extent than that of gold kiwifruit pulp only; however, there was no significant difference between the two. These results indicate that gold kiwifruit consumption significantly suppresses the postprandial blood glucose elevation regardless of pericarp presence or absence and the timing of ingestion. 相似文献
50.
Hiroshi Onimaru Akiko Arata Ikuo Homma 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1995,106(1):57-68
In brainstem-spinal cord preparations isolated from newborn rats, intrinsic burst-generating properties of preinspiratory (Pre-I) neurons in the rostral ventrolateral medulla, which have been suggested to be primary respiratory rhythm-generating neurons, were studied by perforated whole-cell recordings using the antibiotic nystatin. Nystatin causes small pores to be formed in the cells, through which pass small monovalent ions. For blockade of chemical synaptic transmission, perfusate Ca2+ concentration was lowered to 0.2 mM and the Mg2+ concentration was increased to 5 mM. In Iow-Ca2+, high-Mg2+ solution (referred to here as low Ca), 10 of 55 Pre-I neurons generated rhythmic bursts (burst type), 14 fired tonically (tonic type), and 31 were silent (silent type). Burst-type neurons showed periodic depolarization of 5–12 mV in low Ca, at a rate of 12±6.5/min. Hyperpolarization of the membrane caused decrease in or disappearance of the periodic depolarization and prolongation of the cycle period. Thus, the burst generations were voltage dependent. The firing frequency of tonictype neurons was 2.3±1.6 Hz and was decreased by hyperpolarization. In 6 of these neurons, the firing patterns changed to burst patterns during continuous hyperpolarization. Membrane depolarization by continuous outward current injection into some silent-type neurons (3 of 11 tested) induced bursting activity. Activity of C4 and Pre-I neurons was completely silent with 0.1–1 M tetrodotoxin (TTX) added to the standard perfusate. In low Ca, burst-type neurons (n=3) were also silent with 1 M TTX perfusion. Inspiratory neurons either became silent (n=4) or fired tonically (n=1) in low Ca. The present study by perforated whole-cell recordings confirmed that some Pre-I neurons possess intrinsic burst-generating properties, which were not attributable to phasic synaptic inputs. 相似文献