Epigenetic Programming of Porcine Endometrial Function and the Lactocrine Hypothesis     

FF Bartol  AA Wiley  CA Bagnell 《Reproduction in domestic animals》2008,43(S2):273-279

Epigenetic programs controlling development of the female reproductive tract (FRT) are influenced by the effects of naturally occurring bioactive agents on patterns of gene expression in FRT tissues during organizationally critical periods of foetal and perinatal life. Aberrations in such important cellular and molecular events, as may occur with exposure to natural or manmade steroid or peptide receptor-modulating agents, disrupt the developmental program and can change the developmental trajectory of FRT tissues, including the endometrium, with lasting consequences. In the pig, as in other mammals, maternal programming of FRT development begins pre-natally and is completed post-natally, when maternal effects on development can be communicated via signals transmitted in milk. Studies involving relaxin (RLX), a prototypic milk-borne morphoregulatory factor (MbF), serve as the basis for ongoing efforts to identify maternal programming events that affect uterine and cervical tissues in the neonatal pig. Data support the lactocrine hypothesis for delivery of MbFs to neonates as a specific consequence of nursing. Components of a maternally driven lactocrine mechanism for RLX-mediated signalling in neonatal FRT tissues, including evidence that milk-borne RLX is delivered into the neonatal circulation where it can act on RLX receptor (RXFP1) -positive neonatal tissues to affect their development, are in place in the pig. The fact that all newborn mammals drink milk extends the timeframe of maternal influence on neonatal development across many species. Thus, lactocrine transmission of milk-borne developmental signals is an element of the maternal epigenetic programming equation that deserves further study.  相似文献   

A novel severity scoring system for dogs with heatstroke          下载免费PDF全文

Gilad Segev DVM  DECVIM‐CA  Itamar Aroch DVM  DECVIM‐CA  Michal Savoray DVM  Philip H. Kass DVM  MPVM  MS  PhD  Yaron Bruchim DVM  DACVECC 《Journal of Veterinary Emergency and Critical Care》2015,25(2):240-247

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不同日龄混合柄瘤蚜茧蜂对寄主虫龄的选择及子代蜂发育表现     

曹林  李保平  孟玲 《南京农业大学学报》2011,34(4)

对同一头混合柄瘤蚜茧蜂雌蜂连续观察5 d,比较其对蚕豆蚜若蚜和成蚜的选择,并观察了子代蜂的发育特性。结果表明:5日龄蜂对不同虫龄蚜虫的寄生率无显著差异,子代蜂羽化率和雌性比亦无显著差异,但寄生2、3龄若蚜的子代雌蜂体型显著大于寄生其他蚜虫的子代雌蜂,寄生3龄若蚜的子代雄蜂显著大于寄生成蚜的子代雄蜂。在其他日龄(1～4)蜂中,1、4日龄蜂对不同龄若蚜的寄生率无显著差异,但均高于对成蚜的寄生,2、3日龄蜂对2龄若蚜的寄生偏好显著高于对更高虫龄的寄生;3日龄蜂的子代蜂羽化率在各虫龄蚜虫之间无显著差异,其他日龄蜂寄生低龄若蚜的子代羽化率高于寄生较高虫龄蚜虫;寄生中间龄期若蚜(3、4龄)的子代蜂雌性比显著高于寄生1龄或成蚜的子代蜂;1日龄蜂子代雌蜂体型在不同虫龄蚜虫间无显著差异,但2～4日龄蜂寄生2、3龄若蚜的子代雌性体型大于寄生1龄、4龄或成蚜的子代雌蜂;1、2日龄蜂的子代雄蜂体型在各虫龄蚜虫间无显著差异,3、4日龄蜂寄生中间龄期若蚜的子代雄性体型大于寄生1龄若蚜或成蚜。根据本研究结果推测,与低龄蜂相比高龄蜂对寄主品质要求更高,其幼虫对寄主的调节能力更强。  相似文献   

Development of Y‐chromosome‐Specific SCAR Markers Conserved in Taurine,Zebu and Bubaline Cattle     

BCA Alves  VFM Hossepian de Lima  CA Moreira‐Filho 《Reproduction in domestic animals》2010,45(6):1047-1051

Sex pre‐selection of bovine offsprings has commercial relevance for cattle breeders and several methods have been used for embryo sex determination. Polymerase chain reaction (PCR) has proven to be a reliable procedure for accomplishing embryo sexing. To date, most of the PCR‐specific primers are derived from the few single‐copy Y‐chromosome‐specific gene sequences already identified in bovines. Their detection demands higher amounts of embryonic genomic material or a nested amplification reaction. In order to circumvent this, limitation we searched for new male‐specific sequences potentially useful in embryo sexing using random amplified polymorphic DNA (RAPD) analysis. Random amplified polymorphic DNA (RAPD) assay reproducibility problems can be overcome by its conversion into Sequence Characterized Amplified Region (SCAR) markers. In this work, we describe the identification of two bovine male‐specific markers (OPC16₃₂₃ and OPF10₁₁₆₈) by means of RAPD. These markers were successfully converted into SCARs (OPC16₇₂₆ and OPF10₉₈₄) using two pairs of specific primers.Furthermore, inverse PCR (iPCR) methodology was successfully applied to elongate OPC16₃₂₃ marker in 159% (from 323 to 837 bp). Both markers are shown to be highly conserved (similarity ≥95%) among bovine zebu and taurine cattle; OPC16₃₂₃ is also highly similar to a bubaline Y‐chromosome‐specific sequence. The primers derived from the two Y‐chromosome‐specific conserved sequences described in this article showed 100% accuracy when used for identifying male and female bovine genomic DNA, thereby proving their potential usefulness for bovine embryo sexing.  相似文献   

Effect of Recombinant Bovine Somatotropin on Plasma Concentrations of Insulin‐like Growth Factor I,Insulin and Membrane Integrity of Bull Spermatozoa     

MB Vieira  I Bianchi  EM Madeira  VFB Roll  CA Oliveira  P Viau  I Pivato  NC Severo  FAB Del Pino  A Schneider  MN Corrêa 《Reproduction in domestic animals》2010,45(6):1110-1113

This study aimed to evaluate the effect of the exogenous recombinant bovine somatotropin (rbST) on plasma concentrations of insulin‐like growth factor I (IGF‐I), insulin and semen quality of bulls. Twenty bulls (Aberdeen Angus and Brangus) were divided by breed into two groups. Placebo group was injected with NaCl 0.9% (s.c.) and treatment group with rbST (s.c., 500 mg) at days 0 and 14 of the experiment. Immediately after semen collection, blood samples were taken on days 0, 14, 28, 42 and 56 of the experiment. Semen was also collected on day 70 of the experiment. Evaluation of sperm motility was performed at pre‐freezing and post‐thawing stage, whereas assessment of sperm membrane integrity was performed after freezing and thawing. Analysis of data revealed that the effect of treatment and treatment‐by‐collection day on plasma concentrations of IGF‐I and insulin was not significant. However, mean plasma concentrations of IGF‐I and insulin were affected (p < 0.0001) by days of blood sampling. Effect of treatment and treatment‐by‐collection day on motility of spermatozoa was similar (p > 0.05) at pre‐freezing and post‐thawing stage. Intactness of plasmalemma and tail membrane of spermatozoa at post‐thawing stage was higher (p < 0.05) in rbST‐treated group than in control. In conclusion, rbST did not affect plasma concentrations of IGF‐I and insulin, however, it did improve post‐thaw sperm membrane integrity.  相似文献   

Dry matter,nitrogen and phosphorus accumulation,partitioning and remobilization as affected by N and P fertilization and source–sink relations     

Christos Dordas 《European Journal of Agronomy》2009,30(2):129-139

Durum wheat (Triticum turgidum subsp. durum L.) is being increasingly grown in many areas of the world, but there is a lack of information about the physiological processes limiting grain yield. In this study, different rates of N and P fertilization were applied and the source:sink ratio was manipulated to examine the factor(s) limiting grain filling under rainfed conditions. Plants exposed to four fertilization treatments (control, 80 kg N ha^?1 (N), 50 kg P ha^?1 (P) and 80 kg N ha^?1 and 50 kg P ha^?1 (N–P)) and were artificially modified to obtain a range of different source:sink ratios. The treatments were (I) control; (II) half of the spike was removed; (III) all the spike was removed. The cultivar Cosmodur was used, which is widely grown in Greece and other Mediterranean countries and is quite productive especially under rainfed conditions. The distribution of dry matter, N and P among grains, stems and leaves was analyzed at anthesis and harvesting. Dry matter accumulation and partitioning into different plant parts was different between the fertilization treatments and the control. At anthesis, leaf + culm dry matter was higher than the chaff dry matter. Total aboveground biomass increased after anthesis in both years and at all fertilization treatments. N fertilization affected N concentration at the whole plant level at anthesis and at maturity. There was an average increase of 20% in N concentration with N application at anthesis in both years relative to the control. N content was affected by the fertilization treatments and it was increased by 33% over the 2 years of the study compared with the control. In addition, P fertilization affected P concentration both at anthesis and maturity in every plant organ, and there was also a significant effect of the change of P concentration at the two different growth stages. P accumulation was also affected by the fertilization regime and by the spike halving treatment. Dry matter translocation was an average of 22% higher at the fertilized treatments compared with the control, which indicates that fertilization led plants to translocate higher amount of dry matter. N and P translocation were affected by the fertilization treatment and in some treatments by the sink reduction. The spike reduction treatment increased the pre-anthesis contribution to seed indicating that the N and P remobilization from vegetative tissues were very important for grain development. The present study indicates that N and P fertilization and sink size can affect dry matter, N, and P accumulation, partitioning, and retranslocation of durum wheat which can affect seed yield.  相似文献   

绥化市北林区农机化发展经验探讨     

刘丽华  CA Shuquan 《农业科技与装备》2008,(4):106-107

绥化市北林区农机事业在黑龙江省起步比较早,与全省其他市县一道,通过近两代农机人的共同努力,积累了丰富的工作经验。为此,对改革开放以来北林区农机工作进行较系统的总结,旨在为今后优化农机化发展决策提供参考.  相似文献   

长沙市1997～2010年土地利用总体规划实施可持续利用评价   总被引：1，自引：0，他引：1  

尹丽  孙浩  曹政辉 《贵州农业科学》2007,35(3):61-64

以长沙市为例,运用生态足迹的方法对长沙市上轮土地利用总体规划的可持续利用情况进行了全面评价,为更好地修编新一轮土地利用总体规划提供依据,同时提出保持土地可持续利用应采取的措施。  相似文献   

Nitrogen nutrition index and its relationship to N use efficiency in linseed     

Christos A. Dordas 《European Journal of Agronomy》2011,34(2):124-132

Plant-based diagnostic techniques such as the nitrogen nutrition index (NNI) are used to determine the level of crop N nutrition, but research, especially on linseed, is limited. The objectives of this study were to determine whether there is a relationship between the NNI of linseed and N use efficiency (NUE) and to use NNI as a diagnostic tool for predicting seed yield response to N fertilization. The relationship between NNI and NUE was investigated in a two year field study of three linseed cultivars (Livia, Lirina, Creola) under different N fertilization conditions (0, 40, and 80 kg ha^?1). N fertilization affected N concentration in different plant parts. The NNI varied from 0.65 to 1.16 across years, growth stage, and cultivar and was affected by the fertilization level. Linseed NUE and its components (N uptake efficiency and N utilization efficiency) were also affected by the cultivar, N fertilization, growing season, and interactions among these variables. N utilization efficiency accounted for more of the variation of NUE than did N uptake efficiency in most cases, and a negative correlation was found between NUE and N utilization efficiency and also between seed yield and NNI. This study provides new information about the effect of N application on NNI and NUE in linseed. High yields of linseed are dependent on an adequate supply of N, which can be diagnosed using NNI.  相似文献   

Dry matter yield,nitrogen content,and competition in pea–cereal intercropping systems     

A.S. Lithourgidis  D.N. Vlachostergios  C.A. Dordas  C.A. Damalas 《European Journal of Agronomy》2011,34(4):287-294

Intercrops of pea (Pisum arvense L.), a popular legume used in intercropping systems with winter cereals for forage and silage production, with wheat (Triticum aestivum L.), rye (Secale cereale L.), and triticale (× Triticosecale Wittmack) in two seeding ratios (60:40 and 80:20) were compared with monocrops of pea and cereals for two growing seasons. Growth rate, dry matter yield, and N uptake were determined in each intercropping system. Furthermore, several indices were used to evaluate the intercropping systems and analyze the competition and the interrelationships between mixture components. Growth rate of cereals was lower in the mixtures than in the monocrops. Dry matter yield was higher in triticale monocrop, followed by its two intercrops, and the pea–wheat 80:20 intercrop. Moreover, triticale monocrop, pea–triticale intercrops, and pea–wheat 80:20 intercrop showed the highest crude protein yield and N uptake. The land equivalent ratio (LER), relative crowding coefficient (K), actual yield loss (AYL), and system productivity index (SPI) values were greater for the pea–triticale mixtures and the pea–wheat and pea–rye mixtures (80:20), indicating an advantage of intercropping. In most intercrops, the values of partial K, AYL, aggressivity, and competitive ratio (CR) indicated that the cereal was more competitive than pea. The highest values of monetary advantage index (MAI) and intercropping advantage (IA) were recorded for the pea–triticale and the pea–wheat mixtures (80:20). Overall, pea–triticale and pea–wheat mixtures (80:20) were more productive and produced better forage quality than the other mixtures and thus could be adopted by the farmers as alternative options for forage production.  相似文献