Genomic Imprinting in Canis familiaris     

CM Nolan  FM O'Sullivan  DC Brabazon  JJ Callanan 《Reproduction in domestic animals》2009,44(S2):16-21

For the vast majority of mammalian genes, maternally- and paternally-derived alleles behave identically and are either expressed or repressed, regardless of whether they were inherited from egg or sperm. For imprinted genes, however, this is not the case. The alleles of imprinted genes are epigenetically modified in a parent-of-origin-specific manner and, as a consequence, maternally- and paternally-derived alleles behave differently. Typically one allele is expressed while the other is silent. Although relatively few in number, imprinted genes are the focus of intensive study, as they have important roles in embryonic development. Abnormal expression of imprinted genes results in growth disorders and is implicated in several clinical conditions. Most studies of imprinted genes have been performed in rodents or primates, with limited studies in other mammals such as bovine and opossum. We have recently demonstrated the existence of imprinted genes in the canine, by showing that the canine insulin-like growth factor 2 receptor gene ( IGF2R ) is monoallelically expressed, with predominant expression of the maternally-derived allele and repression of the paternally-inherited allele. Our ultimate goal is to characterize all imprinted genes in the canine, and to understand how they contribute to canine reproduction, development and disease. Such knowledge will be vital for optimizing the success of most reproductive strategies in the canine.  相似文献   

p53 dynamics control cell fate     

Purvis JE  Karhohs KW  Mock C  Batchelor E  Loewer A  Lahav G 《Science (New York, N.Y.)》2012,336(6087):1440-1444

Cells transmit information through molecular signals that often show complex dynamical patterns. The dynamic behavior of the tumor suppressor p53 varies depending on the stimulus; in response to double-strand DNA breaks, it shows a series of repeated pulses. Using a computational model, we identified a sequence of precisely timed drug additions that alter p53 pulses to instead produce a sustained p53 response. This leads to the expression of a different set of downstream genes and also alters cell fate: Cells that experience p53 pulses recover from DNA damage, whereas cells exposed to sustained p53 signaling frequently undergo senescence. Our results show that protein dynamics can be an important part of a signal, directly influencing cellular fate decisions.  相似文献   

Inheritance of photosynthesis in a diallel among eight maize inbred lines from Iowa Stiff Stalk Synthetic     

T. M. Crosbie  J. J. Mock  R. B. Pearce 《Euphytica》1978,27(3):657-664

Summary Photosynthesis is a trait that should be improved in a selection program for yield potential of maize (Zea mays L.). We measured leaf CO₂-exchange rate (CER), an estimate of photosynthetic efficiency, of a complete diallel (parents, F₁ crosses, and their reciprocals) among eight inbred lines (4 with low and 4 with high CER) from the Iowa Stiff Stalk Synthetic maize population. Measurements were made during vegetative (CER 1) and grain filling (CER 2) stages of growth, and the experiment was conducted two years at one location. We measured large differences among crosses and significant heterosis for high CER at CER 1 (0.0 to 25.1%) and CER 2 (0.0 to 53.8%). Several crosses exhibited overdominant phenotypes for high CER at both growth stages, and one cross showed significant overdominance for low CER at CER 1. General combining ability effects (gca) were the largest components of among-cross variation at both CER 1 and CER 2. Specific combining ability (sca) also was significant at both growth stages, but gca effects were 9.4 and 4.8 times larger than sca effects at CER 1 and CER 2, respectively. Furthermore, high CER lines showed positive gca effects, and low CER lines showed negative gca effects at each stage. Maternal and reciprocal effects were not significant; thus, CER in these crosses was controlled largely by additive effects of nuclear genes. A high positive genotypic correlation (r=0.74) between CER 1 and CER 2 suggested that selection at either growth stage would improve CER throughout the growing season.Journal Paper No. J-9023 of the Iowa Agriculture and Home Economics Exp. Stn., Ames, Iowa. Project No. 1990.  相似文献   

Changes in morphological and physiological traits associated with recurrent selection for grain yield in maize     

M. A. B. Fakorede  J. J. Mock 《Euphytica》1978,27(2):397-409

Summary Experiments were conducted during the growing seasons of 1975 and 1976 to determine changes in morphological and physiological traits associated with recurrent selection for grain yield in maize (Zea mays L.). Four variety hybrids, BSSS(R)CO x BSCB1(R)CO, BSSS(R)C7 x BSCB1(R)C7 [from a reciprocal recurrent selection program involving Iowa Stiff Stalk Synthetic (BSSS) and Iowa Corn Borer Synthetic #1 (BSCB1)], BS12CO x B14A, and BS12C6 x B14A [from a half-sib selection program involving the open-pollinated variety Alph (BS12) and the inbred tester B14A] were grown at 59 300 and 98 800 plants/ha near Ames, Iowa We obtained data on CO₂-exchange rate (an estimate of photosynthetic rate), grain yield, grain-yield components, flowering dates, maturity traits, light interception and use, shelling percentage, harvest index, and various other plant traits.CO₂-exchange rate did not change appreciably with recurrent selection for yield. Grain yield per hectare and per plant were larger for the improved than unimproved hybrids. Grain-yield components did not change significantly with recurrent selection. Kernel weight of BSSS(R)C7 x BSCB1 (R)C7, however, was larger than that of BSSS(R)C0 x BSCB1(R)C0. Pollen-shed-to-silking interval was shorter for the improved than the unimproved hybrids, and grain-filling duration was longer in C7 x C7 than in C₀ x C₀ of the reciprocal recurrent selection program. Furthermore, improved hybrids were characterized by smaller tassels and more upright canopies. Usually, plant traits and leaf-area-related traits were similar for all hybiids.Although dry-matter productivity was similar for all hybrids, those that were improved by recurrent selection produced more grain per unit leaf area and per unit light interception. Also, BS12C6 x B14A was characterized by a higher harvest index than BS12CO x B14A.We concluded that the source (i.e., photosynthetic capacity) was not limiting grain yield in BSSS(R) x BSCB1(R) and BS12. Increased grain yields that resulted from recurrent selection were consequences of longer grain-filling duration for BSSS(R) x BSCB1(R) and increased translocation of photosynthate from source to sink for both BSSS(R) x BSCB1(R) and BS12.Journal Paper J-8953 of the Iowa Agriculture and Home Economics Exp. Stn., Ames, Iowa. Project No. 2152.  相似文献   

Siblicidal aggression and resource monopolization in birds     

Mock DW 《Science (New York, N.Y.)》1984,225(4663):731-733

In Texas, great egret Casmerodius albus chicks attack younger nestmates, often fatally (siblicide). By contrast, the young of neighboring great blue herons Ardea herodias seldom strike or kill siblings. These interspecific differences seem related to prey size: only fish provided by egret parents are small enough for chicks to monopolize (a process facilitated by aggression). Experimentally cross-fostered heron chicks raised on small prey by egret parents became siblicidal, but the reverse procedure of cross-fostering egret chicks did not reduce aggression or siblicide.  相似文献   

High Embryonic Recovery Rates with In vivo and Ex vivo Techniques in the Bitch     

MR Luz  CC de Holanda  JJ Pereira  PMC Freitas  AEP Salgado  J Di Giorgio Giannotti  SB de Oliveira  NS Teixeira  CR de Freitas Guaitolini 《Reproduction in domestic animals》2011,46(4):724-727

The embryonic collection techniques in dogs present a vast methodological variation and low recovery rates. The objectives were to compare and describe two techniques as to the recovery of canine embryos, on the 12th day after the first mating or artificial insemination. Embryos were recovered through uterine horn flushing in vivo, before performing the ovariohysterectomy (OHE) (Group 1; n = 9) or ex vivo, immediately after the OHE (Group 2; n = 9). In total, 43 and 47 embryonic structures were recovered in Groups 1 and 2, respectively. There was no significant difference (p > 0.05) between groups on recovery rates (72.8% and 81.0%, respectively). We inferred that both in vivo and ex vivo techniques allow a high rate of embryonic recovery; in the collection technique prior to the OHE, it is essential to carefully handle the reproductive system during the trans‐surgical period and that the 12th day (D12) after the first mating/artificial insemination is an efficient option for the high recovery rate of morulae and blastocysts.  相似文献   

Effect of Estradiol and Progesterone on Metabolic Biomarkers in Healthy Bitches     

A Tvarijonaviciute  JD Carrillo‐Sanchez  JJ Ceron 《Reproduction in domestic animals》2013,48(3):520-524

The aim of this study was to evaluate the possible association between hormonal changes that occur during oestrus and biomarkers related with glucose metabolism (glucose and insulin), lipid metabolism (lipidic profile and BChE) and adipokines (adiponectin and ghrelin) in healthy bitches. For this purpose, we measured these analytes in serum of bitches, at two times: before (T1) and after (T2) the LH peak that were established according to progesterone concentrations. Increased levels of total cholesterol (p < 0.01), high density lipoprotein cholesterol (HDL‐C) (p < 0.01), low density lipoprotein cholesterol (LDL‐C) (p < 0.01), adiponectin (p < 0.01) and ghrelin (p < 0.05) were observed at T2 in comparison with T1. No statistically significant changes were observed in serum glucose, insulin, homoeostasis model assessment for insulin sensitivity (HOMA), triglycerides and BChE. When all data of T1 and T2 were pooled, serum adiponectin showed positive correlation with progesterone (r = 0.353; p = 0.022) and HDL‐C (r = 0.307; p = 0.048), and negative with insulin (r = ?0.429; p = 0.005), HOMA (r = ?0.446; p = 0.003) and BChE (r = ?0.522; p < 0.001). Ghrelin showed negative correlation with estradiol (r = ?0.701; p = 0.004). BChE was negatively correlated with estradiol (r = ?0.441; p = 0.018) and glucose (r = ?0.343; p = 0.028), and positively with insulin (r = 0.460; p = 0.003) and HOMA (r = 0.505; p < 0.001). In conclusion, changes in metabolic biomarkers occur in bitches after LH peak, characterized by increased lipids (total cholesterol, HDL cholesterol and LDL cholesterol) without changes in BChE activity, and increased adiponectin and ghrelin concentrations, without significant changes in glucose and insulin.  相似文献   

Oestrous Synchronization,Ovarian Superovulation and Intraspecific Transfers From a Closed Breeding Colony of Inbred SLA Miniature Pigs     

JJ Arlaud  L Baker  RL Williams  AJ French 《Reproduction in domestic animals》2010,45(6):951-958

The inbred SLA miniature pig is a unique animal model developed for organ transplantation studies and pre‐clinical experimental purposes. Reported oestrous synchronization and superovulation treatments were examined in two SLA haplotypes (AA and DD) to allow collection of embryos for both practical embryo transfer and experimental technologies from a closed breeding colony. Pre‐puberal miniature pigs were poor responders to oestrous synchronization treatments, while post‐puberal sows were equivalent to commercial sows. Following superovulation, the ovulation number (corpora .hemorrhagica) was higher (p < 0.05) in the cycling sows when compared with non‐cycling sows. Ovulations were equivalent to commercial pre‐puberal gilts and non‐cycling sows (p > 0.05). No difference in ovulation number between haplotypes was observed, which differs from the previous report (DD>AA). Collection of zygotes for pronuclear injection was the highest in the non‐cycling post‐puberal miniature pig group (p < 0.05), although significantly lower when compared with the commercial pig treatment groups (p < 0.05). The incidence of cystic endometrial hyperplasia in our colony was equivalent to rates observed in commercial pigs. Pronuclear visualization following centrifugation was the highest in the non‐cycling miniature sow group and approximates to about 25% of ovulations and about half the rate observed in the commercial pigs (50%). Miniature pig embryos transferred between SLA haplotypes and transfer of DD embryos to commercial pigs resulted in live births at a higher efficiency than previously reported. This study demonstrates the feasibility of undertaking assisted reproductive technologies in a closed breeding colony of inbred SLA miniature pigs without compromise to the breeding programmes.  相似文献   

Correlation of Rutin Accumulation with 3-O-Glucosyl Transferase and Phenylalanine Ammonia-lyase Activities During the Ripening of Tomato Fruit   总被引：1，自引：1，他引：0  

Esra Capanoglu  Jules Beekwilder  Andrea Matros  Dilek Boyacioglu  Robert D. Hall  Hans Peter Mock 《Plant foods for human nutrition (Dordrecht, Netherlands)》2012,67(4):371-376

In tomato, the predominant flavonoid is quercetin-3-rutinoside (rutin). In this study, we aim to investigate the phenylalanine ammonia-lyase (PAL) and the quercetin-3-O-glucosyl transferase (3-GT) reactions in the formation of rutin during tomato fruit ripening. Tomatoes of the Moneymaker variety at different development stages (green, breaker, turning, pink, red, and deep red) were divided into flesh and peel fractions. In each sample, both the content of rutin and the enzymatic activities for PAL and 3-GT were recorded. The highest activities of PAL were recorded in the peel of turning fruit (3,000 μkat/mg fresh weight). In fruit flesh, maximal activity was observed in red fruit (917.3 μkat/mg). For both tissues, PAL activity strongly decreased at the final (deep red) fruit stage. The activity of 3-GT in peel peaked in the turning fruit stage (50.7 pkat/mg), while in flesh maximal activity (33.4 pkat/mg) was observed in green fruit, which rapidly declined at the turning stage. Higher levels of rutin were detected in the tomato peel compared to the flesh part with the highest level being found at the green stage. The relation of PAL and 3-GT activities to rutin content is also evaluated.  相似文献   

Serum copper, zinc, calcium and phosphorus concentrations of calves stressed by bovine respiratory disease and infectious bovine rhinotracheitis   总被引：1，自引：0，他引：1  

C L Orr  D P Hutcheson  R B Grainger  J M Cummins  R E Mock 《Journal of animal science》1990,68(9):2893-2900

The relationship between serum minerals and stress and(or) disease has not been fully evaluated in beef cattle. Two trials were conducted to determine the changes in serum Cu and Zn during market-transit stress and(or) disease. Two additional trials were conducted to determine the changes in serum Cu and Zn after inoculation with infectious bovine rhinotracheitis virus (IBRV), with one of the trials determining the changes in serum Ca and P. Trials 1 (n = 80) and 2 (n = 100) utilized calves that were handled through a normal market-transit system and transported 1,967 km to the feedlot. Trials 3 (n = 37) and 4 (n = 8) used calves that were sero-negative to IBRV and then challenged with 2.7 x 10(5) plaque-forming units of the virus. Serum samples were collected at specified intervals and serum minerals were measured for each trial. Serum Zn for morbid or IBRV-challenged calves was decreased by 34, 57, 29 and 15% (P less than .05) for the four trials, respectively, at peak morbidity. Serum Cu of morbid or IBRV-challenged calves increased 5, 15, 40 and 33% for the four trials, respectively, at peak morbidity. Feed intakes were lower during morbidity for market-transit trials and after IBRV inoculation. Lower feed intake could partially explain the decrease in serum Zn; however, when feed intake was held constant, serum Zn concentration still decreased. Serum Zn decreased and serum Cu increased during market-transit morbidity or after IBRV.  相似文献