scholarly journals 31EFFECTS OF CYCLOHEXIMIDE ON CAPRINE SOMATIC CELL NUCLEAR TRANSFER EMBRYO AND FETAL DEVELOPMENT

2004 ◽  
Vol 16 (2) ◽  
pp. 138
Author(s):  
R.E Butler ◽  
D. Melican ◽  
N. Hawkins ◽  
T. Jellerette ◽  
S. Nims ◽  
...  

The use of protein synthesis inhibitors to down regulate the levels of Maturation Promoting Factor (MPF) following fusion and activation are widely used in the field of Nuclear Transfer (NT). Cycloheximide is a protein synthesis inhibitor that blocks the levels of cyclin B, a component of MPF which is required to maintain MII stage arrest in oocytes. However, it is unclear what, if any, effects these broadbased inhibitors may have on nonspecific protein expression in the oocytes or karyoplasts. The purpose of this study was to examine the effects of treatment with and without cycloheximide on embryo and fetal development to term. Ovulated in vivo MII oocytes from superovulated does during the traditional breeding season were surgically collected and then enucleated and reconstructed with either transfected fetal or adult skin cell karyoplasts or transgenic primary somatic skin cells. Couplets were simultaneously fused and activated with a single electrical pulse between 2.6 and 3.0kVcm−1 for 20μs. An additional electrical pulse was given to fused couplets and non-fused couplets were re-fused. Reconstructed embryos were either treated with 5μgmL−1 cyclohexamide (Sigma, St. Louis, MO, USA) for a minimum of 3h or cultured directly post-fusion and activation. The embryos were cultured in SOF +BSA at 38°C in a humidified modular incubation chamber (Billrups-Rothenberg, USA) containing 6% O2, 5% CO2, and 89% N2 for 24–48h. Cleavage was assessed, and nuclear transfer embryos, with age appropriate development (up to 2 cells at 24h or 2 to 8 cells by 48h), were surgically transferred to the oviduct of surrogate recipient does. There were 18 and 11 confirmed pregnancies by Day 50 post-fusion and activation from the cycloheximide and non cycloheximide groups, respectively. A total of 12 recipients that received cycloheximide treated embryos produced term pregnancies and yielded 15 offspring. Alternatively, 9 recipients that received untreated embryos produced term pregnancies which yielded 12 offspring. A total of 27 NT offspring were produced and one offspring from a set of quadruplets died several days post-natally. While significantly more cycloheximide treated NT embryos cleaved, there was no significant difference in pregnancy rate or offspring born between treatment groups. These results suggest that the use of cycloheximide for embryo development in somatic cell nuclear transfer may not be necessary for establishing and maintaining caprine NT pregnancies. Table 1

1974 ◽  
Vol 62 (3) ◽  
pp. 707-716 ◽  
Author(s):  
Charles T. Roberts ◽  
Eduardo Orias

Tetrahymena is able to adapt to the presence of sublethal concentrations of many drugs which inhibit a wide variety of cellular functions. In spite of the generality of this phenomenon in Tetrahymena, the mechanism of adaptation at the cellular and molecular levels is unknown. This study deals mainly with adaptation to the protein synthesis inhibitors, cycloheximide and emetine. The physiological response of Tetrahymena to sublethal concentrations of these drugs is an immediate cessation of cell division for a period of time dependent on the drug concentration, followed by an abrupt resumption of exponential growth at a constant rate. By measuring the length of the growth lags under a variety of experimental conditions, we have confirmed several observations made by Frankel and coworkers, and provide evidence for two new phenomena associated with adaptation to cycloheximide: (a) adaptation to cycloheximide also results in adaptation of cells to emetine, another protein synthesis inhibitor not closely related structurally to cycloheximide. We have termed this phenomenon cross adaptation, (b) exposure to concentrations of cycloheximide too low to cause any growth lags or inhibition of protein synthesis significantly shortens the time required by cells to adapt to higher concentrations of cycloheximide. We have termed this phenomenon facilitation. Facilitation shows some degree of specificity in that facilitation with cycloheximide has no effect on adaptation to emetine. From this, we infer the existence of two distinct systems involved in adaptation to cycloheximide, one of which shows a higher degree of specificity towards cycloheximide than the other. We also show that transfer of adapted or facilitated cells to drug-free medium results in a gradual but complete resensitization. The kinetics of resensitization suggest that the cellular machinery responsible for adaptation and facilitation does not leave the cell, but is simply diluted out during cell division.


2015 ◽  
Vol 27 (1) ◽  
pp. 104
Author(s):  
N. L. Selokar ◽  
M. Saini ◽  
H. Agrawal ◽  
P. Palta ◽  
M. S. Chauhan ◽  
...  

Cryopreservation of semen allows preservation of somatic cells, which can be used for the production of progeny through somatic cell nuclear transfer (SCNT). This approach could enable restoration of valuable high-genetic-merit progeny-tested bulls, which may be dead but the cryopreserved semen is available. We have successfully produced a live buffalo calf by SCNT using somatic cells isolated from >10 year old frozen semen (Selokar et al. 2014 PLoS One 9, e90755). However, the calf survived only for 12 h, which indicates faulty reprogramming of these cells. The present study was, therefore, carried out to study the effect of treatment with trichostatin A (TSA), an epigenetic modifier, on reprogramming of these cells. Production of cloned embryos and determination of quality and level of epigenetic markers in blastocysts were performed according to the methods described previously (Selokar et al. 2014 PLoS One 9, e90755). To examine the effects of TSA (0, 50, and 75 nM), 10 separate experiments were performed on 125, 175, and 207 reconstructed embryos, respectively. The percentage data were analysed using SYSTAT 12.0 (SPSS Inc., Chicago, IL, USA) after arcsine transformation. Differences between means were analysed by one-way ANOVA followed by Fisher's least significant difference test for significance at P < 0.05. When the reconstructed buffalo embryos produced by hand-made clones were treated with 0, 50, or 75 nM TSA post-electrofusion for 10 h, the cleavage percentage (100.0 ± 0, 94.5 ± 2.3, and 96.1 ± 1.2, respectively) and blastocyst percentage (50.6 ± 2.3, 48.4 ± 2.7, and 48.1 ± 2.6, respectively), total cell number (274.9 ± 17.4, 289.1 ± 30.1, and 317.0 ± 24.2, respectively), and apoptotic index (3.4 ± 0.9, 4.5 ± 1.4, and 5.6 ± 0.7, respectively) in Day 8 blastocysts were not significantly different among different groups. The TSA treatment increased (P < 0.05) the global level of H4K5ac but not that of H3K18a in embryos treated with 50 or 75 nM TSA compared with that in controls. In contrast, the level of H3K27me3 was significantly lower (P < 0.05) in cloned embryos treated with 75 nM TSA than in embryos treated with 50 nM TSA or controls. The ultimate test of the reprogramming potential of any donor cell type is its ability to produce live offspring. To examine the in vivo developmental potential of the 0, 50, or 75 nM TSA treated embryos, we transferred Day 8 blastocysts, 2 each to 5, 6, and 5 recipients, respectively, which resulted in 2 pregnancies from 75 nM TSA treated embryos. However, one pregnancy was aborted in the first trimester and the other in the third trimester. In conclusion, TSA treatment of reconstructed embryos produced from semen-derived somatic cells alters their epigenetic status but does not improve the live birth rate. We are currently optimizing an effective strategy to improve the cloning efficiency of semen-derived somatic cells.


1971 ◽  
Vol 178 (1053) ◽  
pp. 455-464 ◽  

1. Memory in day-old-chickens during the first few hours after learning can be made to decline by the prior intracranial injection of two classes of drugs. 2. Sodium pump inhibitors in increasing doses cause increasingly rapid loss of memory. 3. Protein synthesis inhibitors in increasing doses attain a maximum potency in causing memory decline and the rate may not be further accelerated by higher doses. 4. Adding a sodium pump inhibitor to the inhibition of protein synthesis increases memory loss. 5. Adding a protein synthesis inhibitor to a sodium pump inhibitor causes no further loss. 6. Therefore within a few minutes of learning a short-term memory of limited time span but independent of protein synthesis becomes supplemented and eventually replaced by a long-term storage requiring protein synthesis. The amount of long-term store is set by the amount of short-term memory. 7. The short-term store could be directly dependent on post-activation enhancement of Na + extrusion from neurons. Some physiological mechanisms by which this could be achieved and how this might activate protein synthesis are discussed.


2009 ◽  
Vol 21 (1) ◽  
pp. 109 ◽  
Author(s):  
G. S. Ajithkumar ◽  
B. Krishnamohan ◽  
B. C. Sarkhel

For cloning by somatic cell nuclear transfer (SCNT) in goat, there are conflicting reports about the proper time of enucleation after IVM of oocytes, which varied from 20 to 27 h (Das SK et al. 2003 Small Rumin. Res. 48, 217–225; Keefer CL et al. 2002 Biol. Reprod. 66, 199–203; Daniel SM et al. 2007 Small Rumin. Res. 77, 45–50). The present investigation has been undertaken to standardize the optimum time of enucleation after IVM of oocytes. The hypothesis behind the study was that enucleation performed during early stages of maturation maintains the MII plate and polar body (PB) in a closer position and therefore makes it easy to enucleate. To test this hypothesis, caprine COCs were aspirated from slaughterhouse ovaries of goats and good quality oocytes were matured in TCM 199 containing 7.5% FBS supplemented with FSH, LH, and estradiol. Enucleation was performed in four different interval groups after IVM (20–23 h, 23–26 h, 26–29 h and 29–32 h). The enucleation of oocytes was conducted as per method described by (Du F et al. 2006 Theriogenology 65, 642–665). Briefly, IVM oocytes were enucleated by squashing and compressing out the first PB along with 10 to 15% of its surrounding cytoplasm with an enucleation needle through a slit made on the zona pellucida. Successful enucleation was confirmed by fluorescent microscopy of removed ooplasm after staining with Hoechst 33342. The enucleation percentage values after arcsine transformation was analyzed by completely randomized design ANOVA. The result of enucleation at different intervals has been summarized in Table 1. There was no significant difference (P > 0.05) in number of PB observed among the four enucleation groups, however the enucleation percentage decreased significantly (P < 0.05) with increase in enucleation time (70.29% and 70.51% in G1 and G2 v. 59.52% and 55.61% in G3 and G4 respectively). With increase in time of enucleation after maturation the size of perivitelline space increases, causing deviation of PB from spindle, thus the success rate of enucleation is reduced (Song K et al. 2007 Repro. Fertil. Dev. 19, 293–294). In G1 and G2 groups the PB and MII chromosomes are located close together with stronger spindle force that requires minimum ooplasm to be removed with higher percentage of successful enucleation. Hence, it was concluded that G1 and G2 groups may be considered as most efficient for enucleation but the developmental potential of reconstructed oocytes after nuclear transfer in each group needs to be tested (study under progress). Table 1.Enucleation results at different intervals


2020 ◽  
Vol 32 (2) ◽  
pp. 135
Author(s):  
M. Yauri Felipe ◽  
M. Duque Rodríguez ◽  
A. De Stéfano ◽  
D. Salamone

Cloning endangered species has the limitation that generally the number of available oocytes is limited. Reprogramming the nuclei heterospecifically using an enucleated oocyte from a different species is an alternative. Aggregation of SCNT (somatic cell nuclear transfer) embryos from the same specie results in improved embryo development. However, after aggregation of heterospecific SCNT embryos from different genera, no effects were observed (Moro et al. 2015 Reproduction 50, 1-10). The objective of this study was to evaluate the influence of aggregation of yak (Bos grunniens) embryos produced by heterospecific SCNT using enucleated oocytes from an animal from the same genus Bos taurus. As control homospecific SCNT of Bos taurus, parthenogenic zone-free embryos and IVF embryos were used. Cumulus-oocyte complexes were recovered from bovine slaughterhouse ovaries by follicular aspiration. The cumulus-oocyte complexes were matured in tissue culture medium 199 containing 10% fetal bovine serum, 10μgmL−1 FSH, 0.3mM sodium pyruvate, 100mM cysteamine, and 2% antibiotic-antimycotic for 22h, at 6.5% CO2 in humidified air and 38.5°C. After denudation, mature oocytes were stripped of the zona pellucida using a protease and then enucleated by micromanipulation. Staining was performed with Hoechst 33342 to observe MII. Enucleated oocytes were placed in phytohemagglutinin to induce adherence with the donor cell followed by electrofusion. All reconstituted embryos were activated using ionomcine. This was followed by a treatment with 6-dimethylaminopurine for 3h. Zona-free reconstituted cloned embryos were cultured in the wells of the well system, placing one (1×) or two (2×) per microwell, in synthetic oviductal fluid medium. The experimental groups were parthenogenic zone free; IVF; reconstituted embryos bull fibroblast-enucleated oocyte from cow (BC1×); reconstituted embryos yak fibroblast-enucleated oocyte from cow (YC1×); and reconstituted embryos aggregated yak fibroblast-enucleated oocyte from cow (YC2×). In all experimental groups, cleavage of at least one embryo in the wells and blastocyst formation at Day 7 were assessed. The effect of cloned embryo aggregation on blastocyst rates was analysed using Fisher exact tests (GraphPad Prisma 8), and results are shown on Table 1. Results demonstrated that aggregation of two SCNT heterospecific embryos increased the blastocyst formation rate of yak (P&lt;0.05). In conclusion aggregation in yak heterospecific SCNT embryos from species of the same genus (Bos) can improve development to blastocyst. Table 1.Aggregation of yak heterospecific somatic cell nuclear transfer embryos Experimental group1 No. of embryos No. of embryos-wells2 Cleavage (%) Blastocyst (%) PZF 68 68 66 (97.06%)a 17 (25.00%)acd IVF 89 - 81 (91.01%)ab 39 (43.82%)b BC1× 45 45 41 (91.11%)b 6 (13.33%)cd YC1× 101 101 77 (76.24%)c 14 (13.86%)c YC2× 134 67 61 (91.04%)ab 21 (31.34%)ab a-dDifferent superscripts in the same column indicate significant difference (Fisher's exact test, P&lt;0.05). 1PZF, parthenogenetic zone free; IFV, IVF fecundation; BC1×, clone of bovine; YC1×, clone of yak-bovine; YC2×, clone of yak-bovine added. 2Wells used with embryos.


2010 ◽  
Vol 76 (23) ◽  
pp. 7691-7698 ◽  
Author(s):  
Anne E. Taylor ◽  
Lydia H. Zeglin ◽  
Sandra Dooley ◽  
David D. Myrold ◽  
Peter J. Bottomley

ABSTRACT A method was developed to determine the contributions of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) to the nitrification potentials (NPs) of soils taken from forest, pasture, cropped, and fallowed (19 years) lands. Soil slurries were exposed to acetylene to irreversibly inactivate ammonia monooxygenase, and upon the removal of acetylene, the recovery of nitrification potential (RNP) was monitored in the presence and absence of bacterial or eukaryotic protein synthesis inhibitors. For unknown reasons, and despite measureable NPs, RNP did not occur consistently in forest soil samples; however, pasture, cropped, and fallowed soil RNPs commenced after lags that ranged from 12 to 30 h after acetylene removal. Cropped soil RNP was completely prevented by the bacterial protein synthesis inhibitor kanamycin (800 μg/ml), whereas a combination of kanamycin plus gentamicin (800 μg/ml each) only partially prevented the RNP (60%) of fallowed soils. Pasture soil RNP was completely insensitive to either kanamycin, gentamicin, or a combination of the two. Unlike cropped soil, pasture and fallowed soil RNPs occurred at both 30�C and 40�C and without supplemental NH4 + (≤10 μM NH4 + in solution), and pasture soil RNP demonstrated ∼50% insensitivity to 100 μM allyl thiourea (ATU). In addition, fallowed and pasture soil RNPs were insensitive to the fungal inhibitors nystatin and azoxystrobin. This combination of properties suggests that neither fungi nor AOB contributed to pasture soil RNP and that AOA were responsible for the RNP of the pasture soils. Both AOA and AOB may contribute to RNP in fallowed soil, while RNP in cropped soils was dominated by AOB.


2018 ◽  
Author(s):  
A. A. Tiunova ◽  
D. V. Bezryadnov ◽  
D.R. Gaeva ◽  
V.S. Solodovnikov ◽  
K.V. Anokhin

AbstractA common assumption from experiments that interfere with memory consolidation is that the resultant amnesia returns the brain of an animal to a tabula rasa state with respect to disturbed experience. However, recent studies in terrestrial snail classical conditioning revealed an odd phenomenon: animals were unable to relearn conditioned avoidance of specific food after this memory had been impaired by protein-synthesis inhibitors or N-methyl-D-aspartate (NMDA) receptor antagonists. Here we examined whether such specific memory reacquisition deficit can also be observed in vertebrate learning. We trained day-old chicks in a one-trial passive avoidance task by presenting them a bead of a specific color covered with a repellent substance, methyl anthranilate. Training was preceded by administration of the protein synthesis inhibitor anisomycin or the NMDA receptor antagonist MK-801. Both drugs produced permanent amnesia, and no spontaneous recovery of memory was observed. A second training was given to the amnestic animals either using a bead of the same color (retraining) or a new color (novel training). The interval between the first and second training was 2 or 24 h, and the retention test was given from 30 min to 48 h after the second training. Retraining of the amnestic chicks with the bead that was presented during the initial training failed to produce new avoidance memory for this stimulus at all the between-training and training-to-test intervals. This memory reacquisition deficit was specific and was not transferred to a new conditioned stimulus, which was readily learned. We suggest that such pharmacologically induced experience-specific anterograde amnesia might reflect general properties of normal memory allocation, and we discuss its possible neural bases.


1980 ◽  
Vol 84 (1) ◽  
pp. 1-15
Author(s):  
J. W. Jacklet

1. The circadian rhythm of compound action potentials (CAP) frequency recorded from the isolated eye of Aplysia in culture medium and darkness was subjected to step and pulse treatments with anisomycin, a protein synthesis inhibitor. 2. The step application of anisomycin and its continued presence in the culture medium lengthened the period of the rhythm in a dose-dependent manner. At 10(−8) M the period was increased from the normal 26.5 h to about 28 h and at 10(−7) M the period was lengthened to 31 h or longer. At 10(−6) M the rhythm was suppressed but the CAP activity continued without the cyclic variations in CAP frequency. 3. Six-hour pulses of anisomycin at 10(−6) M caused phase-dependent phase-shifts of the rhythm. Maximum phase delays of 15 h were obtained at CT (circadian time) 2 and maximum phase advances of 4 h were obtained at CT 6. The phase response curves at 12, 15 and 17 degrees C were essentially identical. 4. Anisomycin appears to act rather selectively on the circadian clock mechanism. It does not alter the CAP amplitude and duration and it does not alter the bursting pacemaker mechanism of the optic nerve CAP or central neurones. 5. The results support the hypothesis that the synthesis of a protein or polypeptide on eucaryotic ribosomes is an essential part of the circadian clock timing mechanism. The sensitivity of the clock to anisomycin is the same at three different temperatures (12, 15 and 17 degrees C) within the physiological range of temperatures for Aplysia, as expected for a clock whose period length is temperature compensated (Q10 1.02) over that same range. 6. At the critical phases of CT 1-4, anisomycin pulses often caused unusual perturbations of the rhythm. These effects are consistent with the hypothesis that the circadian rhythm is a multioscillator system.


2007 ◽  
Vol 19 (1) ◽  
pp. 163
Author(s):  
Y. Tao ◽  
W. Han ◽  
M. Zhang ◽  
J. Ding ◽  
X. Zhang

We reported the birth of a goat clone produced by somatic cell nuclear transfer. The fusion and activation protocols of reconstructed oocytes and embryo transfer procedure were optimized. The donors of somatic cells were fibroblasts derived from ear skin of a Boer goat while the recipient ooplasm was in vitro-matured oocytes of Huanghuai white goat, an Anhui native goat species. The reconstructed embryos were activated by ionomycin, 6-dimethylaminopurine (6-DMAP), and cytochalasin B (CB) singly or simultaneously (termed as Ionomycin, Ionomycin+6-DMAP, and Ionomycin+6-DMAP+CB). The result showed that the cleavage rate in single ionomycin was significantly lower than that in Ionomycin+6-DMAP and 6-DMAP+CB (34.38% vs. 69.85% and 72.02%; P &lt; 0.05). However, the cleavage rates and blastocyst rates had no significant difference after in vitro culture (P &gt; 0.05). When the cloned embryos were co-cultured with fetal mouse fibroblast monolayer, the blastocyst development rate increased. The reconstructed embryos were equilibrated 1–3 h, 3–6 h, and 6–9 h after fusion, and then activation was undertaken by ionomycin+6-DMAP. We found that the cleavage rates had no significant difference during 1–3 h and 3–6 h (72.58% vs. 72.97%; P &gt; 0.05), but both were significantly higher than during 6–9 h (64.40%) (P &lt; 0.05). A total of 491 reconstructed embryos were surgically transferred into 37 recipient surrogates, Huanghuai white goats with natural estrus. One of those who were treated with hCG after transfer was pregnant and gave birth to a live kid on 153 days. The lamb died accidentally 8 h after birth. The cloned offspring was then dissected and proved well in all organs. Staining of paraffin tissue slices of the viscera suggested that the organs developed well. Microsatellite analysis indicated that the lamb was derived from the somatic cell donor doe genetically.


2012 ◽  
Vol 24 (1) ◽  
pp. 128
Author(s):  
G. Kim ◽  
H. J. Oh ◽  
J. E. Park ◽  
M. J. Kim ◽  
E. J. Park ◽  
...  

Histocompatible tissue has been generated by somatic cell nuclear transfer (SCNT) and the resultant tissues were not rejected by the immune system of the nucleus donors. In addition, many transgenic animals combined with SCNT have been produced. However, in vitro immunogenicity of transgenic cloned animals originated from the same donor cell with nontransgenic cloned animals has not been assessed until now. The objective of this study was to evaluate the in vitro immunogenicity of cloned dogs with each other, between cloned dogs and transgenic cloned dogs and between transgenic cloned dogs with each other by mixed lymphocyte reaction. In this study, we used cloned beagles (BG1, 2) derived from SCNT using fetal fibroblasts (BF3). Serially, 4 transgenic cloned beagles (Ruppy 1–3, 5) were also genetically engineered from the same donor cell, BF3, with red fluorescent protein (RFP) gene inserted into their genome. We used 2 age-matched healthy female beagle dogs as control dogs. They have different 3 DLA types with all cloned dogs. Peripheral blood mononuclear cells (PBMC) of 2 cloned beagles and 4 transgenic cloned beagles were isolated from whole bloods using Ficoll gradient solution. PBMC from each dog were mixed to auto PBMC, other transgenic cloned dogs and non-related control dogs under the experimental designs. All the mixtures were incubated at 37°C for 4 days, adding BrdU labeling reagent and re-incubated for 24 h. Results are expressed in absorbance mean value ± standard deviation of 450-nm wavelength read by microplate reader. Each cell combination was assayed in 8 replicates. In Experiment 1, PBMC of cloned beagles were combined with equal concentrations of another cloned beagle's PBMC. In Experiment 2, PBMC suspension of Ruppy 1–3, 5 were mixed with equal concentrations of another transgenic cloned beagle's PBMC suspension. In Experiment 3, PBMC suspensions of cloned beagles were mixed with PBMC suspensions of transgenic cloned beagles and reverse reaction was performed. Statistical analysis was performed by using Mann-Whitney U test. In Experiment 1, whereas the absorbance value of mixture of cloned dogs and control dogs shows apparent proliferation, auto mixture of each dog and allo-mixture of BG1 and BG2 show no proliferation (Table 1), indicating immunological factors exposed to PBMC in 2 cloned dogs were compatible. In Experiment 2 among transgenic cloned dogs, no evidence of proliferations in mixed allo-PBMC was shown (Table 1), suggesting in vitro immunogenicity between transgenic cloned dogs was also not shown. In Experiment 3 among cloned dogs and transgenic cloned dogs, no significant difference was found (Table 1). In conclusion, cloned dogs derived from SCNT shared immunological phenotype. Next, immunogenicity among transgenic cloned beagle dogs was not shown despite random insertion of a foreign gene. Lastly, cloned beagles and transgenic cloned beagles show lymphocyte antigen compatibility irrespective of having a foreign gene or not. Table 1.The absorbance values of mixed lymphocytes of 4 transgenic cloned dogs and 2 cloned dogs This study was supported by RNL BIO (#0468-20110001), IPET, MKE (#10033839-2011-13) and Natural Balance Korea.


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