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21.
At 40 day intervals, groups of 87 to 142 commercial ewes of mixed breeding were subjected to a 5 day breeding period, following one of three estrus inducing or synchronizing treatments (intravaginal sponges containing 60 mg of medroxyprogesterone acetate) for 12 days with (progestin P.M.S.G. group) or without pregnant mares serum gonadotropin (P.M.S.G.) (Progestin group) at sponge removal, or a single injection of prostaglandin F(2alpha) (breeding season and early anestrus only) (PGF(2alpha) group)). Mean pregnancy rates (ewes lambing of those treated) and lambing percentages (lambs born per 100 ewes lambing) were 31 +/- 4%, 169 +/- 6%, 20 +/- 5%, 105 +/- 2% and 18 +/- 8%, 118 +/- 3%, respectively, for the three treatment groups above. Pregnancy rates for the progestin, P.M.S.G. group were 52% in late July, prior to the breeding season, 52% in September and declined to 14% in March (early anestrus). The time from the first of two daily injections of estradiol benzoate to lambing was 34.5 +/- 4.4 hours in ewes 142 to 146 days pregnant. 相似文献
22.
Jugular plasma progesterone concentrations were used to accurately predict open ewes (96 +/- 3%) in early pregnancy, but they less accurately predicted subsequent lambing especially during the late breeding season and most of the seasonal anestrus. Progesterone values clearly indicated that 500 I.U. of P.M.S.G. elevated ovulation rate in synchronized ewes, but did not clearly indicate fetal numbers. During late pregnancy (88-108 days), abdominal palpation, doplar ultrasound and serum progesterone analysis were equally efficacious in predicting lambing (86 +/- 9.8%, 90 +/- 9.0% and 87 +/- 4.1%, respectively), but a high percentage of ewes lambed that were diagnosed as nonpregnant (30 +/- 15.0%, 48 +/- 17.3% and 25 +/- 8.4%, respectively). Accuracy of the serum progesterone test improved the later the test was performed, although considerable individual overlap existed. Progesterone values for ewes bearing 1, 2, or greater than 2 fetuses at 94 to 95 days of gestation differed (5.5 +/- 0.3, 8.0 +/- 0.4 and 12.4 +/- 2.1, respectively (P < 0.05), whereas at 103 to 108 days values for ewes carrying two or more fetuses did not differ. 相似文献
23.
24.
K H Mayo M Nunez C Burke C Starbuck D Lauffenburger C R Savage 《The Journal of biological chemistry》1989,264(30):17838-17844
The binding kinetics of 125I-labeled mouse epidermal growth factor (EGF) to receptors on human fibroblast cells in monolayer culture were measured at 4 degrees C. Initial binding rates as a function of hormone concentration allowed estimation of simple two-state on-off rate constants of 1.2 x 10(6) M-1 s-1 and 4.9 x 10(-3) s-1, respectively. These two-state parameters gave inadequate computer fits to long term kinetic and equilibrium-binding data, suggesting that an additional process(es) was occurring. Nonlinear equilibrium Scatchard plots and transient "pseudo-Scatchard" plots taken at pre-equilibrium times support the idea that at least one other process is occurring during receptor binding. 125I-EGF-receptor dissociation kinetic plots were biphasic, yielding rate constants of 1.5 x 10(-2) s-1 and 5.6 x 10(-5) s-1 with the ratio of the two components changing with the time of initial incubation with 125I-EGF. Application of a ternary complex model which assumed complexation of the bound receptor with a cell surface interaction molecule gave satisfactory fits to all data. 相似文献
25.
The influence of the long-acting somatostatin analogue, SMS 201-995, on FMLP-induced neutrophil elastase release in vitro has been investigated. Doses from 150 ng/ml upwards inhibited elastase release, with 100% inhibition by 2500 ng/ml. Inhibition was demonstrated both by an assay measuring elastase immunometrically and by an assay based on its enzyme activity. The demonstration that SMS 201-995 inhibits protease release from polymorphonuclear leukocytes may have implications for the long-term clinical use of this somatostatin analogue. 相似文献
26.
Evidence for an Elongation/Reduction/C1-Elimination Pathway in the Biosynthesis of n-Heptane in Xylem of Jeffrey Pine 总被引:1,自引:0,他引:1
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The biosynthetic pathway to n-heptane was investigated by examining the effect of the [beta]-keto acyl-acyl carrier protein synthase inhibitor (2R,3S)-2,3-epoxy-4-oxo-7E,10E-dodecadienamide (cerulenin), a thiol reagent ([beta]-mercaptoethanol), and an aldehydetrapping reagent (hydroxylamine) on the biosynthesis of n-[14C]heptane and putative intermediates in xylem sections of Jeffrey pine (Pinus jeffreyi Grev.& Balf.) incubated with [14C]acetate. Cerulenin inhibited C18 fatty acid biosynthesis but had relatively little effect on radiolabel incorporation into C8 fatty acyl groups and n-heptane. [beta]-Mercaptoethanol inhibited n-heptane biosynthesis, with a corresponding accumulation of radiolabel into both octanal and 1-octanol, whereas hydroxylamine inhibited both n-heptane and 1-octanol biosynthesis, with radiolabel accumulation in octyl oximes. [14C]Octanal was converted to both n-heptane and 1-octanol when incubated with xylem sections, whereas [14C]1-octanol was converted to octanal and n-heptane in a hydroxylamine-sensitive reaction. These results suggest a pathway for the biosynthesis of n-heptane whereby acetate is polymerized via a typical fatty acid synthase reaction sequence to yield a C8 thioester, which subsequently undergoes a two-electron reduction to generate a free thiol and octanal, the latter of which alternately undergoes an additional, reversible reduction to form 1-octanol or loss of C1 to generate n-heptane. 相似文献
27.
Keith R. Roesler Linda J. Savage David K. Shintani Basil S. Shorrosh John B. Ohlrogge 《Planta》1996,198(4):517-525
Acetyl-CoA carboxylase (ACCase; EC 6.4.1.2) is a regulatory enzyme of fatty acid synthesis, and in some higher-plant plastids is a multi-subunit complex consisting of biotin carboxylase (BC), biotin-carboxyl carrier protein (BCCP), and carboxyl transferase (CT). We recently described a Nicotiana tabacum L. (tobacco) cDNA with a deduced amino acid sequence similar to that of prokaryotic BC. We here provide further biochemical and immunological evidence that this higher-plant polypeptide is an authentic BC component of ACCase. The BC protein co-purified with ACCase activity and with BCCP during gel permeation chromatography of Pisum sativum L. (pea) chloroplast proteins. Antibodies to the Ricinus communis L. (castor) BC co-precipitated ACCase activity and BCCP. During castor seed development, ACCase activity and the levels of BC and BCCP increased and subsequently decreased in parallel, indicating their coordinate regulation. The BC protein comprised about 0.8% of the soluble protein in developing castor seed, and less than 0.05% of the protein in young leaf or root. Polypeptides cross-reacting with antibodies to castor BC were detected in several dicotyledons and in the monocotyledons Hemerocallis fulva L. (day lily), Iris L., and Allium cepa L. (onion), but not in the Gramineae species Hordeum vulgare L. (barley) and Panicum virgatum L. (switchgrass). The castor endosperm and pea chloroplast ACCases were not significantly inhibited by long-chain acyl-acyl carrier protein, free fatty acids or acyl carrier protein. The BC polypeptide was detected throughout Brassica napus L. (rapeseed) embryo development, in contrast to the multi-functional ACCase isoenzyme which was only detected early in development. These results firmly establish the identity of the BC polypeptide in plants and provide insight into the structure, regulation and roles of higherplant ACCases.Abbreviations ACCase
acetyl-CoA carboxylase
- ACP
acyl carrier protein
- BC
biotin carboxylase
- BCCP
biotin carboxyl carrier protein
- CT
carboxyl transferase
- MF
multi-functional
- MS
multi-subunit
We thank our colleagues Nicki Engeseth and Vicki Eccleston for advice on fatty acid analysis and Sarah Hunter for providing the developing Iris seed. This work was supported in part by grant MCB 9406466 from NSF. Acknowledgement is also made to the Michigan Agriculture Experiment Station for its support of this research. 相似文献
28.
Anne M. Donigan R. Christopher Cavalli Angel A. Pena C. Richard Savage Dianne Robert Soprano Kenneth J. Soprano 《Journal of cellular physiology》1993,155(1):164-170
WI-38 cells, density arrested for short periods of time, can be stimulated to re-enter the cell cycle by epidermal growth factor (EGF) alone. However, cells density arrested for longer periods have a prolonged prereplicative phase when serum stimulated and cannot be stimulated by EGF alone. Radio-ligand binding studies performed on WI-38 cells showed that actively growing cells bind [125I]EGF at relatively low levels that increase to a maximum as the cells become contact inhibited. As the cells enter a state of deeper quiescence, EGF binding falls to one-third to one-fifth the short-term growth arrested levels, remaining constant thereafter. The EGF-receptor complexes internalize more slowly in long-term growth arrested cells, and the rate of ligand association to the receptor is lower than short-term growth arrested cells. The amount of EGF receptor protein in lysates of equal numbers of both short- and long-term quiescent cells remains the same. These results suggest that the failure of long-term growth arrested cells to respond to EGF is not due to dramatic changes in the amount of receptor protein during prolonged quiescence but more likely to an alteration in the ability of these receptors to bind ligand and/or activate the EGF signal transduction pathway. © 1993 Wiley-Liss, Inc. 相似文献
29.
G. Mattson E. Conklin S. Desai G. Nielander M. D. Savage S. Morgensen 《Molecular biology reports》1993,17(3):167-183
The various aspects of chemical crosslinking are addressed. Crosslinker reactivity, specificity, spacer arm length and solubility characteristics are detailed. Considerations for choosing one of these crosslinkers for a particular application are given as well as reaction conditions and practical tips for use of each category of crosslinkers.Abbreviations ABH
azidobenzoyl hydrazide
- ANB- NOS
N-5-azido-2-nitrobenzoyloxysuccinimide
- ASIB
1-(p-azidosalicylamido)-4-(iodoacetamido)butane
- ASBA
4-(p-azidosalicylamido)butylamine
- APDP
N-[4-(p-azidosalicylamido) butyl]-3(2-pyridyldithio)propionamide
- APG
p-azidophenyl glyoxal monohydrate
- BASED
bis-[-(4-azidosalicylamido)ethyl] disulfide
- BMH
bismaleimidohexane
- BS3
bis(sulfosuccinimidyl) suberate
- BSOCOES
bis[2-(succinimidooxycarbonyloxy)ethyl]sulfone
- DCC
N,N-dicyclohexylcarbodiimide
- DFDNB
1,5-difluoro-2,4-dinitrobenzene
- DMA
dimethyl adipimidate·2HCl
- DMP
dimethyl pimelimidate·2HCl
- DMS
dimethyl suberimidate·2HCl
- DPDPB
1,4-di-(3,2-pyridyldithio)propionamido butane
- DMF
dimethylformamide
- DMSO
dimethylsulfoxide
- DSG
disuccinimidyl glutarate
- DSP
dithiobis(succinimidylpropionate)
- DSS
disuccinimidyl suberate
- DST
disuccinimidyl tartarate
- DTSSP
3,3-dithiobis (sulfosuccinimidylpropionate)
- DTBP
dimethyl 3,3-dithiobispropionimidate·2HCl
- EDC or EDAC
1-ethyl-3-(3-dimethylaminopropyl)carbodimide hydrochloride
- EDTA
ethylenediaminetetraacetic acid disodium salt, dihydrate
- EGS
ethylene glycolbis(succinimidylsuccinate)
- GMBS
N--maleimidobutyryloxysuccinimide ester
- HSAB
N-hydroxysuccinimidyl-4-azidobenzoate
- HEPES
4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid
- MBS
m-maleimidobenzoyl-N-hydroxysuccinimide ester
- MES
4-morpholineethanesulfonic acid
- NHS
N-hydroxysuccinimide
- NHS-ASA
N-hydroxysuccinimidyl-4-azidosalicylic acid
- PMFS
phenylmethylsulfonyl fluoride
- PNP-DTP
p-nitrophenyl-2-diazo-3,3,3-trifluoropropionate
- SAED
sulfosuccinimidyl 2-(7-azido-4-methylcoumarin-3-acetamide) ethyl-1,3-dithiopropionate
- SADP
N-succinimdyl (4-azidophenyl)1,3-dithiopropionate
- SAND
sulfosuccinimidyl 2-(m-azido-o-nitrobenzamido)-ethyl-1,3-dithiopropionate
- SANPAH
N-succinimidyl-6(4-azido-2-nitrophenyl-amino)hexanoate
- SASD
sulfosuccinimidyl 2-(p-azidosalicylamido)ethyl-1,3-dithiopropionate
- SATA
N-succinimidyl-S-acetylthioacetate
- SDBP
N-hydroxysuccinimidyl-2,3-dibromopropionate
- SIAB
N-succinimidyl(4-iodoacetyl)aminobenzoate
- SMCC
succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate
- SMPB
succinimidyl 4-(p-maleimidophenyl) butyrate
- SMPT
4-succinimidyloxycarbonyl--methyl--(2-pyridyldithio)-toluene
- sulfo-BSOCOES
bis[2-sulfosuccinimidooxycarbonyloxy) ethyl]sulfone
- sulfo-DST
disulfosuccinimidyl tartarate
- sulfo-EGS
ethylene glycolbis(sulfosuccinimidylsuccinate)
- sulfo-GMBS
N--maleimidobutyryloxysulfosuccinimide ester
- sulfo-MBS
m-maleimidobenzoyl-N-hydroxysulfosuccinimide ester
- sulfo-SADP
sulfosuccinimidyl(4-azidophenyldithio)propionate
- sulfo-SAMCA
sulfosuccinimidyl 7-azido-4-methylcoumarin-3-acetate
- sulfo-SANPAH
sulfosuccinimidyl 6-(4-azido-2-nitrophenylamino)hexanoate
- sulfo-SIAB
sulfosuccinimidyl(4-iodoacetyl)aminobenzoate
- sulfo-SMPB
sulfo-succinimidyl 4-(p-maleimidophenyl)butyrate
- sulfo-SMCC
sulfosuccinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate
- SPDP
N-succinimidyl 3-(2-pyridyldithio)propionate 相似文献
30.
Jennifer D. Watts Mary Farina John S. Kimball Luke D. Schiferl Zhihua Liu Kyle A. Arndt Donatella Zona Ashley Ballantyne Eugénie S. Euskirchen Frans-Jan W. Parmentier Manuel Helbig Oliver Sonnentag Torbern Tagesson Janne Rinne Hiroki Ikawa Masahito Ueyama Hideki Kobayashi Torsten Sachs Daniel F. Nadeau John Kochendorfer Marcin Jackowicz-Korczynski Anna Virkkala Mika Aurela Roisin Commane Brendan Byrne Leah Birch Matthew S. Johnson Nima Madani Brendan Rogers Jinyang Du Arthur Endsley Kathleen Savage Ben Poulter Zhen Zhang Lori M. Bruhwiler Charles E. Miller Scott Goetz Walter C. Oechel 《Global Change Biology》2023,29(7):1870-1889
Arctic-boreal landscapes are experiencing profound warming, along with changes in ecosystem moisture status and disturbance from fire. This region is of global importance in terms of carbon feedbacks to climate, yet the sign (sink or source) and magnitude of the Arctic-boreal carbon budget within recent years remains highly uncertain. Here, we provide new estimates of recent (2003–2015) vegetation gross primary productivity (GPP), ecosystem respiration (Reco), net ecosystem CO2 exchange (NEE; Reco − GPP), and terrestrial methane (CH4) emissions for the Arctic-boreal zone using a satellite data-driven process-model for northern ecosystems (TCFM-Arctic), calibrated and evaluated using measurements from >60 tower eddy covariance (EC) sites. We used TCFM-Arctic to obtain daily 1-km2 flux estimates and annual carbon budgets for the pan-Arctic-boreal region. Across the domain, the model indicated an overall average NEE sink of −850 Tg CO2-C year−1. Eurasian boreal zones, especially those in Siberia, contributed to a majority of the net sink. In contrast, the tundra biome was relatively carbon neutral (ranging from small sink to source). Regional CH4 emissions from tundra and boreal wetlands (not accounting for aquatic CH4) were estimated at 35 Tg CH4-C year−1. Accounting for additional emissions from open water aquatic bodies and from fire, using available estimates from the literature, reduced the total regional NEE sink by 21% and shifted many far northern tundra landscapes, and some boreal forests, to a net carbon source. This assessment, based on in situ observations and models, improves our understanding of the high-latitude carbon status and also indicates a continued need for integrated site-to-regional assessments to monitor the vulnerability of these ecosystems to climate change. 相似文献