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51.
Undernutrition before and after calving has a detrimental effect on the fertility of dairy cows. The effect of nutritional stress was previously reported to influence gene expression in key tissues for metabolic health and reproduction such as the liver and the genital tract early after calving, but not at breeding, that is, between 70 and 90 days post‐partum. This study investigated the effects of pre‐ and post‐partum mild underfeeding on global gene expression in the oviduct, endometrium and corpus luteum of eight multiparous Holstein cows during the early and middle phases of an induced cycle 80 days post‐partum. Four control cows received 100% of energy and protein requirements during the dry period and after calving, while four underfed received 80% of control diet. Oestrous synchronization treatment was used to induce ovulation on D80 post‐partum. Oviducts, ovaries and the anterior part of each uterine horn were recovered surgically 4, 8, 12 and 15 days after ovulation. Corpora lutea were dissected from the ovaries, and the endometrium was separated from the stroma and myometrium in each uterine horn. The oviduct segments were comprised of ampulla and isthmus. RNAs from ipsi‐ and contralateral samples were pooled on an equal weight basis. In each tissue, gene expression was assessed on a custom bovine 10K array. No differentially expressed gene (DEG) in the corpus luteum was identified between underfed and control, conversely to 293 DEGs in the oviduct vs 1 in the endometrium under a false discovery rate (FDR) < 0.10 and 1370 DEGs vs 3, respectively, under FDR < 0.15. Additionally, we used dedicated statistics (regularized canonical correlation analysis) to correlate the post‐partum patterns of six plasma metabolites and hormones related to energy metabolism measured weekly between calving and D80 with gene expression. High correlations were observed between post‐partum patterns of IGF‐1, insulin, β‐hydroxybutyrate and the expression in the oviduct of genes related to reproductive system disease, connective tissue disorders and metabolic disease. Moreover, we found special interest in the literature to retinoic acid‐related genes (e.g. FABP5/CRABP2) that might indicate abnormalities in post‐partum tissue repair mechanisms. In conclusion, this experiment highlights relationships between underfeeding and gene expression in the oviduct and endometrium after ovulation in cyclic Holstein cows. This might help to explain the effect of mild undernutrition on fertilization failure and early embryonic mortality in post‐partum dairy cows.  相似文献   
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To improve the Boer goat semen quality during cryopreservation process, three experiments were carried out to investigate the effect of (i) different concentration of ascorbic acid supplementation (ii) rate of cooling with chilled semen characteristics and (iii) method of freezing on post‐thaw Boer goat sperm using Tris‐based extender. Ascorbic acid at 8.5 mg/ml improved the sperm parameters (motility, integrity of membrane and acrosome, morphology and viability), compared to control in cooled samples (p < 0.05). With regard to other concentrations and post‐thawed parameters, ascorbic acid at 2.5–8.5 mg/ml led to higher percentages of sperm motility and integrities of membrane and acrosome when compared to control (p < 0.05). Slow cooling rises to higher percentages of sperm motility, acrosome integrity and viability, in comparison with fast cooling, in terms of cooled and frozen samples (p < 0.05). Programmable freezing method produced the higher percentages of sperm motility, integrities of membrane and acrosome and viability when compared to the freezing method of polystyrene box during goat sperm freezing (p < 0.05). In conclusion, chilled and post‐thawed sperm quality of Boer goat was improved when a Tris‐based extender supplemented with ascorbic acid was used at stages of different cooling rates and freezing methods.  相似文献   
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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   
55.
Evaporative cooling during late gestation period improves post‐partum reproductive performance in Murrah buffaloes. To prove this hypothesis, sixteen pregnant dry Murrah buffaloes at sixty days pre‐partum were selected and divided into two groups of eight animals each. Group 1 of buffaloes (Cooled/CL) was managed under fan and mist cooling during dry period, whereas second group of buffaloes (non‐cooled/NCL) remained without the provision of cooling. After parturition, all the animals were managed under evaporative cooling till the end of experimental period. Reproductive performance in cooled (CL) and non‐cooled (NCL) groups, respectively, viz. 1st and 2nd ovulation from calving (48.63 ± 2.41, 69.25 ± 2.34 days and 57.75 ± 3.35, 93.63 ± 2.84 days); calving to conception interval (117.88 ± 4.21 days and 117.88± 4.21 days); conception rate (87.5% ± 2.16% and 57% ± 2.26%); and follicular diameter at the time of 1st and 2nd ovulation (14.84 ± 0.16, 15.75 ± 0.13 mm and 12.65 ± 0.13, 13.35 ± 0.11 mm) varied significantly (p < .05). Total peak oestrogen concentration was significantly (p < .05) higher in cooled (26.7 ± 1.32 pg/ml) relative to non‐cooled (20.7 ± 1.22 pg/ml) buffaloes. Time from onset of oestrus to ovulation varied significantly (p < .05) in cooled (32 ± 2.22 hr) and non‐cooled (40 ± 2.86 hr) buffaloes. The peak progesterone concentration reached to (4.25 ng/ml) in cooled group and (4.16 ng/ml) in non‐cooled group after first ovulation.  相似文献   
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Carbon structures with three-dimensional periodicity at optical wavelengths   总被引:1,自引:0,他引:1  
Porous carbons that are three-dimensionally periodic on the scale of optical wavelengths were made by a synthesis route resembling the geological formation of natural opal. Porous silica opal crystals were sintered to form an intersphere interface through which the silica was removed after infiltration with carbon or a carbon precursor. The resulting porous carbons had different structures depending on synthesis conditions. Both diamond and glassy carbon inverse opals resulted from volume filling. Graphite inverse opals, comprising 40-angstrom-thick layers of graphite sheets tiled on spherical surfaces, were produced by surface templating. The carbon inverse opals provide examples of both dielectric and metallic optical photonic crystals. They strongly diffract light and may provide a route toward photonic band-gap materials.  相似文献   
58.
The aim of this study was to evaluate the influence of two vitrification techniques on the extra cellular matrix (ECM) and ovarian follicular development. The ovarian cortex was fragmented (9 mm3) and divided into six groups, viz. fresh control, cultured control, vitrified by the Ovarian Tissue Cryosystem (OTC) method, conventional solid surface vitrification (SSV) method, OTC/cultured and SSV/cultured. Follicles from all the fragments were analysed for morphology, development and viability. The ECM was evaluated based on the condition of collagen and reticular fibres and the immunolocalization of type I collagen and fibronectin. After 7 days of culture, the tissue vitrified by OTC revealed a higher percentage (p < 0.05) of morphologically normal (30.66%) and viable (60.00%) follicles when compared with those vitrified using the SSV technique (21.33% and 23.00%). In all the fragments cultured, regardless of the vitrification method, a significantly higher percentage of developing follicles was observed when compared with the non‐cultured tissue. Analysis of the type I collagen showed increased immunostaining after the in vitro culture in the vitrified fragments. In conclusion, the OTC is better for preserving the follicular viability and morphology and maintaining the integrity of the extracellular matrix components of the ovine ovary.  相似文献   
59.
The aim of this study was to isolate Toxoplasma gondii and determine the viability of the parasite in fresh semen samples of clinically healthy adult dogs naturally infected. Eleven seropositive dogs with T. gondii IgG antibodies from southern Brazil were selected to confirm the presence and viability of T. gondii in fresh semen samples using in vitro isolation in Vero cell culture, polymerase chain reaction (PCR) and sequencing analysis. The presence of viable T. gondii was confirmed by in vitro isolation and PCR in five semen samples. The ITS1 region of the isolated protozoa (TG S4) was amplified and sequenced. The nucleotide sequence obtained was 99% compatible with the T. gondii DNA sequences stored in the GenBank. It has been shown that T. gondii tachyzoites may be isolated in vitro from fresh semen samples of clinically healthy dogs seropositive for T. gondii.  相似文献   
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