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11.
Successful breeding of the giant panda (Ailuropoda melanoleuca) following artificial insemination was achieved at the Ueno Zoo in 2 consecutive years (1985 and 1986). The first cub, born in June 1985, unfortunately died 43 hours after birth from being crushed by the mother panda; the second cub, born in June 1986, has been growing in good health. Electroejaculation and artificial insemination procedures were performed after immobilization with diazepam (0.1 mg/kg) and ketamine HCL (4.0–5.0 mg/kg). Semen of the male panda was collected by electroejaculation using a rectal probe with a diameter of 2.0 cm and with eight rings as electrodes. Stimulation of the male was given with 3 V (30–40 mA) over a 5-sec period with 5-sec intervals. The female panda exhibited estrus between late February and early March in 1985 and also between mid-january and early February 1986. Increased excretion of urinary total estrogen showed coincidentally at maximum behavioral estrus, and a gradual rise of pregnanediol level was followed by artificial insemination. The gestational length for the first pregnancy was 110 days and that of the second 121 days. 相似文献
12.
Anti-epidermal growth factor receptor antibodies inhibit the autocrine-stimulated growth of MDA-468 human breast cancer cells 总被引:5,自引:0,他引:5
B W Ennis E M Valverius S E Bates M E Lippman F Bellot R Kris J Schlessinger H Masui A Goldenberg J Mendelsohn 《Molecular endocrinology (Baltimore, Md.)》1989,3(11):1830-1838
The response of malignant and nonmalignant human breast cell lines to the growth inhibitory effects of monoclonal antibodies against the epidermal growth factor (EGF) receptor was studied. A series of human breast cell lines, which express EGF receptor, were used: MDA-468, MDA-231, and Hs578T human breast cancer cells and the transformed human mammary epithelial cell lines 184A1N4 and 184A1N4-T that have been benzo[a]pyrene immortalized and further transformed with SV40T, respectively. Four antibodies of two different classes were tested: 225 immunoglobulin G (IgG), 108.4 IgG, 96 immunoglobulin M (IgM), and 42 IgM. All four antibodies inhibited the anchorage-dependent and -independent, EGF-stimulated growth of 184A1N4 and 184A1N4-T cells, respectively, and this growth inhibition could be reversed by the addition of increasing concentrations of EGF. In contrast, the antibodies inhibited the anchorage-dependent and -independent growth of MDA-468 cells in the absence of exogenous EGF suggesting that the antibodies were acting to block access of an endogenously produced ligand to the EGF receptor. In the presence of antibody and increasing concentrations of EGF, MDA-468 cell growth was first stimulated then inhibited as the EGF concentration increased, thus, uncovering the growth stimulatory potential of low concentrations of EGF in these cells. Data is presented that indicates MDA-468 cells secrete a transforming growth factor with autocrine growth stimulatory capabilities. The growth of MDA-231 and Hs578T cells, which contain activated ras oncogenes, was not inhibited by the antibodies and the growth of these cell lines was not stimulated by EGF. Of the cell lines studied only MDA-468 cells appear to possess an autocrine growth stimulatory capacity. 相似文献
13.
Kato Ryoichi; Takatsuna Sachiko; Wada Tsuyoshi; Narihara Yumi; Suzuki Takashi 《Plant & cell physiology》1996,37(5):667-672
Five-mm sections of elongation zones of Zea mesocotyls wereincubated for designated periods with various concentrationsof IAA. In vitro protein phosphorylation in the soluble fraction(85,000 x g supernatant) prepared from the sections was analyzedby sodium dodecyl sulfate-polyacrylamide gel electrophoresis.The phosphorylation of proteins in the soluble fraction thathad been prepared from sections incubated for 20 min in thepresence of 10{small tilde}s M IAA was greater than that inthe sections incubated for 20 min without IAA. The amount ofphosphorylation of proteins per protein became higher when higherconcentrations increased (10{small tilde}810{small tilde}5M).The growth of sections incubated in the presence of 10{smalltilde}8 M IAA or higher concentrations was greater than thatof sections incubated in the absence of IAA. The promotion ofgrowth by IAA was greater at higher concentrations of IAA. Proteinsin the soluble fraction, prepared from sections incubated for20 min in the presence of 10{small tilde}5 M IAA, were phosphorylatedin the presence of either 10 fM cAMP, 10 µM cGMP, 100µM W-7, 100 µM W-5, 20 µM H-7 or 20 µMHA1004. The calmodulin antagonist, W-7, and the inhibitor ofprotein kinase C, H-7, inhibited the phosphorylation of proteinsstimulated by incubation with IAA. These results suggest thatIAA promotes cell elongation via protein phosphorylation thatdepends on calmodulin-dependent protein kinase and protein kinaseC. (Received November 29, 1995; Accepted May 20, 1996) 相似文献
14.
Thomas Pazdernik Robert Cross Stanley Nelson Yumi Kamijo Fred Samson 《Neurochemical research》1994,19(11):1393-1400
A poorly understood marked decrease (circa 50% of control) in local cerebral glucose utilization is caused by sublethal doses of NaCN. The decrease is global, occurring in essentially all brain regions and is entirely reversible within hours, leaving no obvious pathology. This event is not unique to NaCN in so far as a strikingly similar pattern of decreased glucose utilization occus with some other toxins. Nor can it be attributed to a direct action of NaCN since local application by microdialysis to the striatum produces a global depression. These results imply that some widely distributed system or substance is involved. We speculate the existence of a system possibly related to the reticular activating system that senses a fall in energy production and acts globally to make cells quiescent and thus would give some protection from excitotoxic driven damage.Special issue dedicated to Dr. Sidney Ochs. 相似文献
15.
Laboratory experiments were conducted to test the hypothesis that widelyforaging generalist lizard,Eumeces okadae, visually discriminates palatable queen ants from unpalatable worker ants. The workers ofCamponotus japonicus andLasius niger were rejected on sight, while the queens of both species were eaten with little prior chemical examination by tongue flicks
or licks. Comparison of the lizards' responses towards the workers and wingless queens of similar size indicated that neither
body size nor presence or absence of wings accounted for difference in responses toward the 2 ant castes. The lizards probably
discriminated different ant castes by body proportions. 相似文献
16.
17.
The role of the molybdenum cofactor (Mo cofactor) in the translocationof dimethyl sulfoxide (DMSO) reductase to the periplasmic spacewas studied in vivo by isolating chlorate-resistant mutantsof Rhodobacter sphaeroides f. sp. denitrificans. More than 50%of the chlorate-resistant mutants isolated were defective inthe biosynthesis of the Mo cofactor and all of these mutantsaccumulated the precursor form of the enzyme. About 45% of themutants contained the same level of Mo cofactor as the parentstrain and exhibited normal levels of DMSO reductase and nitratereductase activities when chlorate was absent from the medium,but the activities of these enzymes were depressed when chloratewas present. Much of the accumulated precursor form of the enzymein a Mo cofactor-deficient mutant was bound to the cytoplasmicmembrane and was sensitive to treatment with proteinase K fromthe periplasmic side of the membrane, an indication that theprecursor was exposed on the periplasmic surface of the membrane.The precursor accumulated on the membrane of the parent strainwhen molybdate was removed from the medium or upon additionof tungstate and this precursor was also sensitive to the treatmentwith proteinase K from the periplasmic side. These results suggestthat the Mo cofactor is necessary for proteolytic processingof the precursor to the mature enzyme on the periplasmic sideof the membrane, whereas binding of the precursor to the membraneand translocation across it can occur in the absence of thecofactor. Almost all of the Mo cofactor available for directreconstitution in vitro of nitrate reductase activity from thenit-l mutant of Neurospora crassa was present in the cytoplasmicfractions. (Received December 11, 1991; Accepted March 25, 1992) 相似文献
18.
Haruo Katakura Miyuki Shioi Yumi Kira 《Evolution; international journal of organic evolution》1989,43(5):1045-1053
Crossing experiments and food-choice tests show that two sympatric species of phytophagous ladybird beetles, Epilachna niponica and E. yasutomii, are reproductively isolated by host-plant specificity. Adult beetles selected their natural hosts when given choices, though some accepted the host of the other species when no choice was offered. In each species, survival of larvae to the second instar was significantly higher on their own host plant. No evidence for sexual isolation, gametic isolation, hybrid inviability, or reduced hybrid fertility was detected. Reproductive isolation by host specificity is an important prerequisite for certain models of sympatric speciation. Although the present example supports the plausibility of such models, an allopatric origin of host-plant specificity cannot be discounted. 相似文献
19.
By monitoring 45Ca2+ influx and efflux from oocytes a transient increase followed by a transient decrease in the Ca2+-content of progesterone-treated oocytes was observed. Chelation of intracellular Ca2+ with EGTA or BAPTA-type buffers inhibited progesterone-induced GVBD. Buffers with a mid-range Kd (∼1.5 μm) were most effective in inhibiting GVBD whereas buffers with a Kd above or below this value were less effective. These observations indicate that intracellular Ca2+, probably in the form of a localized release, is required for progesterone-induced oocyte maturation. However, Ca2+ alone was insufficient to induce GVBD. When the effects of nocodazole and taxol upon this Ca2+-requirement were tested, we observed that taxol-induced microtubule polymerization not only delayed progesterone-induced
GVBD but also completely inhibited it in combination with BAPTA-AM. Conversely, nocodazole-induced microtubule depolymerization
in combination with ionophore A23187 not only accelerated progesterone-induced GVBD, but also induced GVBD in the absence
of progesterone. The combined treatment of oocytes with nocodazole and InsP3, or with cold treatment and ionophore A23187 also induced GVBD in the absence of progesterone. Thus, Ca2+ and microtubule depolymerization synergistically promote GVBD. In both nocodazole- and cold-treated oocytes, the GV was displaced
to the periphery of the oocyte and underwent GVBD when treated with A23187. However, when the GV was displaced to the cortex
by a centrifugal force under conditions that would not cause microtubule depolymerization and the oocyte was treated with
A23187, oocytes did not undergo GVBD.
Received: 19 January 1996 / Accepted: 21 May 1996 相似文献
20.
Potential Distribution and Ionic Concentration at the Bean Root Surface of the Growing Tip and Lateral Root Emerging Points 总被引:1,自引:0,他引:1
Watanabe Yumi; Takeuchi Satoshi; Ashisada Mitsuo; Ikezawa Yasunari; Takamura Tsutomu 《Plant & cell physiology》1995,36(4):691-698
The electrical potential distribution has been measured preciselyaround the root surface of the bean sprout Vigna mungo (L) Hepper.A large negative potential well was found at the growth portionof the root tip. Also, in the matured region of the root, wefound a negative potential well at an unspecified position inspite of the fact that nothing was detected on the smooth surface.A lateral root emerge was found to have initiated after 1520hours just at the position corresponding to the potential well.With the expectation that these potentials can be elucidatedbased on the transport of ions which are released or absorbedby the root as a result of cell activity, we precisely measuredthe concentrations of major ion species (K+, H+, and Cl)around the root. The theoretical potential distribution curvesobtained by putting all the concentration data into the Henderson'sEquation for a liquid junction (diffusion) potential coincidedwell with the experimental curves. (Received October 24, 1994; Accepted March 24, 1995) 相似文献