This review presents a broad overview of chorionic glycoproteins encoded by the Pregnancy-Associated Glycoprotein (PAG) gene family and also serves to illustrate how the recent discovery of the PAG family has contributed to our general knowledge of genome evolution, placental transcription and placental protein expression. The complex and large PAG family is restricted to the Artiodactyla order, although single PAG-like genes have also been identified in species outside the Artiodactyla. The PAGs are members of the aspartic proteinase (AP) superfamily. Unexpectedly, however, some members of the PAG family possess amino acid substitutions within and around the active site that likely render them unable to act as proteinases. This paper summarises the available information regarding biodiversity of PAG gene expression based on cDNA cloning, mRNA localisation studies and the structural organisation of the PAG genes with a particular emphasis on PAG promoters. It also compares available data regarding PAG protein purifications, sequencing and their N-glycodiversity. Finally, it discusses the scientific relevance, possible functional roles of the PAGs and describes possible profitable applications related to the detection of PAG proteins in the blood of pregnant domestic and wild species.
The objective of this study was to investigate the possible effect of demecolcine, a microtubule-disrupting reagent, on induced enucleation (IE) of sheep meiotically maturing oocytes. Immunofluorescent staining with anti-tubulin antibodies was used to examine the spindle status of the oocytes. When the oocytes with intact germinal vesicles (GV) were cultured in the medium containing various concentrations of demecolcine (0.01 to 0.4 microg.mL-1) for 20 to 22 h, the spindle microtubule organization and first polar body (PB1) extrusion were inhibited by demecolcine in a dose-dependent manner. The highest IE rate (58.1%) was from the treatment with 0.04 microg.mL-1 demecolcine. Demecolcine treatment applied after germinal vesicle breakdown (GVBD) or at metaphase (M) yielded a PB1 extrusion rate and IE efficiency similar to the treatment applied at the onset of maturation. Analysis by immunofluorescence showed that both nonspindle microtubules and spindle microtubules were significantly disorganized by demecolcine. Combination treatment with demecolcine and cycloheximide (CHX) or 6-dimethylaminopurine (6-DMAP) led to single pronuclear formation rather than PB1 extrusion. When demecolcine-treated oocytes were transferred into demecolcine-free medium, the ability to extrude PB1 was quickly restored and a 72.1% IE rate was obtained following such treatment. These results demonstrate that demecolcine can be used as a potential reagent for induced enucleation of sheep meiotically maturing oocytes and may greatly facilitate research in nuclear transfer.
The study was aimed at analysing body size in relation to form of gonad maturation (amount of mature germ cells) in 329 under-yearling sea trout males. The fish, aged 7 months, were caught in late October-early November in 3 streams located in north-western Poland. Each stream supported fish belonging to a different sib group. Standard histological techniques and a computer image analysis programme were used to detect the class of gonad maturation and percentage of the gonad area occupied by tubules with active spermatogenesis. Gonad maturation forms were distinguished based on the latter criteria. Gonads with developing germ cells occupying less than 90% of gonad area were classified as incomplete forms of gonad maturation, others as complete maturation forms. In each sib-groups analysed, even the smallest individual were already precocious, their gonads being incompletely mature. The smallest maturing male measured 7.1 cm in length. The average size of an incompletely maturing individual was slightly smaller than that of the completely mature one but the difference lacked statistical significance (P > 0.05). The sib-group of smaller fish contained less precocious, and the gonads of the more precocious were incompletely mature, compared to the sib-group of larger fish (P < 0.001). It seems that the incomplete form of gonad maturation (defected maturation) occurs at a smaller critical fish size than the complete gonad maturation form. Incomplete maturation is more frequent smaller individuals and possibly in among slow-growing groups of fish.
An experiment combining a hyperinsulinemic euglycemic clamp procedure of four sequential 2-h periods and an isotope dilution method of [U-13C]glucose determined the effect of supplemental calcium propionate on blood glucose metabolism during insulin and glucose infusions in adult sheep. They were fed lucerne hay cubes and commercial concentrate with and without supplementary calcium propionate (Prop and Cont diets, respectively) in a crossover design for each 21-day period. At the preinfusion period, blood glucose turnover rate (GTR) was greater (P < 0.05) for the Prop diet than for the Cont diet. Blood GTR, endogenous glucose production rate (EGPR) and the ratio of EGPR to blood GTR were greater (P < 0.01, P < 0.05 and P < 0.05, respectively) for the Prop diet than for the Cont diet. Blood GTR and glucose infusion rate (GIR) increased (P < 0.001) and the ratio of EGPR to blood GTR was reduced (P < 0.01) with increased insulin infusion rates. The maximal GIR tended to be (P < 0.10) greater for the Prop diet than for the Cont diet but plasma insulin concentration at half maximal GIR did not differ between diets. It is suggested that in adult sheep, dietary propionate supplementation enhances insulin action on glucose metabolism, however, changes in measures of tissue responsiveness and sensitivity were not significant.
Data from a previous study about the effects of pH and of linolenic acid (C18:3n-3) and linoleic acid (C18:2n-6) concentrations on C18:2n-6 biohydrogenation in ruminal cultures were used to calculate the rates and efficiencies of the three reactions of C18:2n-6 biohydrogenation (isomerisation of C18:2n-6 to CLA; reduction of CLA to trans-octadecenoic acids; reduction of trans-octadecenoic acids to stearic acid). First, low pH was confirmed to inhibit isomerisation and was shown to inhibit the second reduction, leading to an accumulation of vaccenic acid. This later effect had only been observed in some in vivo studies using high concentrate diets, because in in vitro experiments, the very low pH frequently used depresses isomerisation which consequently generates very low amount of substrates for reductions whose variations become difficult to ascertain. Second, C18:2n-6 at high concentration was confirmed to saturate its own isomerisation and the increase of CLA production due to high initial C18:2n-6 was shown to inhibit the two subsequent reductions. Third, C18:3n-3 at high concentrations was confirmed to inhibit C18:2n-6 isomerisation. Moreover, the second reduction was shown to be saturated, probably by all trans-octadecenoic acids intermediates of C18:2n-6 and C18:3n-3 biohydrogenation, leading to an accumulation of trans-octadecenoic acids, especially vaccenic acid. This fatty acid is partly desaturated into CLA in the mammary gland, which explains the synergy between C18:2n-6 and C18:3n-3 for milk CLA noticed by others in vivo. This approach helped explain the actions of pH and of C18:2n-6 and C18:3n-3 concentrations on C18:2n-6 biohydrogenation and allows some explanations about differences noticed between studies.
The objective of the study was to examine how the fatty acid composition of milk especially concentrations of conjugated linoleic acids (CLA) and trans-C18:1 isomers and milk fat percentage were affected by silage type and concentrate level. Forty dairy cows were blocked and randomly assigned to one of four diets in a 2 x 2 factorial arrangement of treatments and a six week experimental period. Treatments were total mixed rations with maize (M) or grass (G) silage differing in polyunsaturated fatty acid (PUFA) profile and starch content, combined with a high (H) or a low (L) level of concentrate (with or without grain). Treatments had no significant effect on milk, protein and lactose yield, but energy corrected milk yield, milk fat percentage and fat yield was lower and protein percentage higher for maize compared with grass silage diets. Overall, maize silage diets resulted in higher concentrations of CLA isomers compared with grass silage diets, but there was a significant interaction between silage type and concentrate level for concentrations of cis9,trans11-CLA; trans10,cis12-CLA; trans11-C18:1 and trans10-C18:1. A high level of concentrate increased trans10,cis12-CLA and trans10-C18:1 and reduced cis9,trans11-CLA and trans11-C18:1 when maize but not grass silage was provided. The results suggest that high levels of concentrate (grain) do not significantly alter the pattern of PUFA biohydrogenation in the rumen, the concentration of CLA and trans-C18:1 isomers in milk or cause milk fat depression unless combined with forage naturally high in starch and C18:2n-6 such as maize silage.
The main sulphated proteins secreted by rat mammary gland tissue have Mr of approximately 32 000, 27 000 and 25 000 Da. In addition, there are high Mr components which have a diffuse electrophoretic mobility (Mr > 200 000) and most likely corresponded to proteoglycans. The sulphate groups in the proteins with discrete Mr are most likely all linked to carbohydrates. These sulphated molecules were partially purified and identified to isoforms of rat alpha-lactalbumin for the 25-27 kDa bands and to kappa-casein for the 32 kDa band. This pattern of protein sulphation is, as far as we know, quite specific to rat mammary epithelial cells.
The fetal demand for docosahexaenoic acid (DHA) has to be satisfied by the mother. We determined the fatty acids in maternal plasma non-esterified fatty acid (NEFA), triacylglycerol (TAG) and phosphatidylcholine (PC), in a cross-sectional study of non-pregnant (n = 10), pregnant (n = 19), and postpartum (n = 9) women. There were lipid class-dependent differences in plasma polyunsaturated fatty acid (PUFA) concentrations between groups. During pregnancy, DHA was most highly enriched in PC, about 230%, with more modest enrichment for linoleic acid (LA) and arachidonic acid (AA), and no enrichment of alpha-linolenic acid (alpha-LNA). There was relative enrichment of LA, AA and alpha-LNA in TAG, but not of DHA. There was no specific enrichment of any PUFA in the NEFA pool. These data accord with the suggestion that the enrichment of alpha-LNA in TAG and of DHA in phospholipids reflects hepatic regulation of n-3 PUFA metabolism which potentially enhances the delivery of DHA to the placenta.
The beneficial effects of nutrition on reproduction in sheep have been described, particularly on ovulation rate. However, the relationships between nutrition and reproductive seasonality are not well known. This review will deal with the effects of body fat or food intake on sexual and hypothalamic/pituitary activity in sheep, mainly focused on Mediterranean genotypes. Although only severe malnutrition can significantly extend the length of the seasonal anestrous period, the level of fat reserves can play a significant role on reproductive seasonality delaying the onset of seasonal anoestrus, particularly on the Mediterranean environment. The effect of overfeeding on LH secretion has also been reported, specially at short term. Several experimental approaches have elucidated that both high body fat and food intake are able to modify the sensitivity of the hypothalamus to oestradiol negative feedback during seasonal anoestrus, with those effects being associated to a reduced amount of NPY mRNA and to an increase of plasma insulin, glucose and leptin concentrations, particularly in the late scenario. However, the highest receptivity to nutritional stimulation in terms of increasing LH occurs when ewes are subjected to a photoperiodic state of early anoestrus or late breeding season rather than under a photoperiod characteristic of the end of anoestrus or the beginning of the breeding season.
Hereinafter are several reviews and original articles issued from the presentations made at the fifth meeting of an INRA research network bringing together investigators from different departments of the institute in the converging areas of mammary gland biology and milk. This year's programme featured presentations covering a wide range of topics relating to mammary gland differentiation, with emphasis on omic approaches of the biology of the tissue, and on milk protein and lipid biosynthesis and secretion. The programme of the last session included several aspects of livestock farming on the functioning of mammary tissue and the milk products biogenesis. Attending the meeting were around 50 participants representing 15 research structures. Much credit should be given to the organizers of the sessions (F. LeProvost and M. Ollivier-Bousquet, INRA Jouy-en-Josas; M. Boutinaud, INRA Rennes) who obtained a successful blend of talks. Another distinguishing feature of the meeting was its diverse range of speakers, including PhD students and young investigators. As in previous years, several participants decided to share their work and concepts further by submitting manuscripts to Reproduction, Nutrition, Development; many thanks to them. We do hope to continue reporting on our annual meeting in the future publication ANIMAL, following the merger of Reproduction, Nutrition, Development into this new international journal of animal biosciences. Our thanks are also due to all those contributors and participants who, in our view, made the meeting a success. We are also grateful to the referees for their cooperation, and to all concerned by the editorial process.
Experiments were conducted to detect interferon-tau in bovine in vitro-derived blastocysts by transmission electron (TEM) and confocal microscopy. TEM showed the presence of IFN-tau in the cytoplasm and the nuclei of expanded blastocysts. Confocal microscopy similarly confirmed the presence of IFN-tau in the trophectoderm of blastocysts. The distribution of IFN-tau appeared variable with some cells showing strong labeling while others appeared to be devoid of the protein.
Cystic ovarian follicles (COF) are an important ovarian dysfunction and a major cause of reproductive failure in dairy cattle. Due to the complexity of the disorder and the heterogeneity of the clinical signs, a clear definition is lacking. A follicle becomes cystic when it fails to ovulate and persists on the ovary. Despite an abundance of literature on the subject, the exact pathogenesis of COF is unclear. It is generally accepted that disruption of the hypothalamo-pituitary-gonadal axis, by endogenous and/or exogenous factors, causes cyst formation. Secretion of GnRH/LH from the hypothalamus-pituitary is aberrant, which is attributed to insensitivity of the hypothalamus-pituitary to the positive feedback effect of oestrogens. In addition, several factors can influence GnRH/LH release at the hypothalamo-pituitary level. At the ovarian level, cellular and molecular changes in the growing follicle may contribute to anovulation and cyst formation, but studying follicular changes prior to cyst formation remains extremely difficult. Differences in receptor expression between COF and dominant follicles may be an indication of the pathways involved in cyst formation. The genotypic and phenotypic link of COF with milk yield may be attributed to negative energy balance and the associated metabolic and hormonal adaptations. Altered metabolite and hormone concentrations may influence follicle growth and cyst development, both at the level of the hypothalamus-pituitary and the ovarian level.
Reproductive protocols based on standard (Control: 11 days post-partum) or extended rhythm (PW: post-weaning at 27 days post-partum) were compared. Two groups of fifty 19-week-old New Zealand White females were inseminated for seven consecutive cycles. The kits were weaned at 26 days. On the day of AI, all the does were submitted to ultrasound scanning of the perirenal regions to measure fat thickness. The fertility rate and several indexes of efficiency were calculated. Fat thickness, estimated perirenal fat and live weight were higher in PW does. The does submitted to post-weaning rhythm had a higher sexual receptivity (P < 0.01), and fertility rate (P < 0.01) whereas litter size and pre-weaning mortality were not affected. Primiparous Control does showed a particularly low fertility rate; the value increased successively but was always lower than in PW does. PW rhythm in comparison with the standard one seemed more adapted to doe reproductive physiology even if there was a lower production (35.0 vs. 38.8 rabbit sold/year) and risk of fatness (18% of multiparous does).
The pattern of vaginal cell exfoliation during the oestrous cycle period was studied in cycling and non-descript West African dwarf (WAD) goats. The exfoliated epithelial cells were categorised into parabasal, intermediate and superficial and their relative occurrences were used to determine the reproductive status of the cycling and non-descript does. The mean cell counts of the epithelial and leucocyte cells were also compared between the days of cycle. Leucocyte and epithelial cells were present in the vaginal smears of the WAD does throughout the cycle. Cell counts increased sharply on days 1 and 2 after standing oestrus. From day 4 of the cycle, the counts fell back to the levels at oestrus and daily variations thereafter were not striking enough to distinguish between the different stages of the cycle. In the non-descript does, the intermediate cell dominated the majority of the smears, which is the typical pattern of cell exfoliation in anoestrus and peri-pubertal does. In the smears from cycling does, however, superficial cells were more frequently observed and they appeared to be associated with the proestrus, oestrus and early metoestrus phases of the cycle. These results indicate that the pattern of exfoliation of vaginal cells could be used to determine the reproductive condition and by extension the ovarian functioning of the WAD goats.
Change in metabolic status, defined as a change in the availability of nutrients and energy to the tissues, is a powerful regulator of the reproductive function in small ruminants, especially in genotypes that are not strongly responsive to photoperiod such as the Merino sheep. In this paper, the dynamics of the response of the reproductive axis to changes in metabolic status are reviewed in the light of recent studies. The nature and the roles of the various components of the pathways linking metabolic status to reproduction are considered: nutrients and metabolites, the endocrine system, and the nervous system. We discuss the role of leptin and insulin in detail because of the central role of these two hormones in both the early gonadotrophin response to increase in nutrition and the long-term response of the testis to dietary stimulation. The possible roles of recently identified peptides, such as ghrelin and kisspeptin, are also considered as we develop a general hypothesis that encompasses the different levels of integration necessary to explain the complex interactions between reproductive function and metabolic status, and the possible existence of a "metabolic memory" in this interaction.
Milk is a very abundant source of proteins for animal and human consumption. Milk composition can be modified using transgenesis, including exogenous gene addition and endogenous gene inactivation. The study of milk protein genes has provided researchers with regulatory regions capable of efficiently and specifically driving the expression of foreign genes in milk. The projects underway are aimed at modifying milk composition, improving its nutritional value, reducing mammary infections, providing consumers with antipathogen proteins and preparing purified recombinant proteins for pharmaceutical use. The present paper summarises the current progress in this field.
In mammals, radical oxygen species (ROS) are essential factors of cell replication, differentiation and growth (oxidative signal), notably during gestation, but are also potentially damaging agents. In Women, ROS play a role in remodeling of uterine tissues, implantation of the embryo, settlement of the villi and development of blood vessels characteristic of gestation. The body stores of vitamins and minerals of gestating females are used to keep ROS fluxes at a level corresponding to oxidative signals and to prevent an imbalance between their production and scavenging (oxidative stress), which would be detrimental to the mother and fetus. There is some evidence that, although based on different regulatory mechanisms, most of the effects of ROS reported in humans also occur in pregnant ruminant females, some of which have been actually reported. Many vitamins and trace elements have dual effects in the organism of mammals: (a) they are involved in the control of metabolic pathways or/and gene expression, (b) but most of the time they also display ROS trapping activity or their deficiencies induce high rates of ROS production. Deficiencies induce different disorders of gestation and can be induced by different kinds of stress. An example is given, corresponding to the decreased contents of cobalt of forages, when exposed to sustained heavy rains, so that the supply of vitamins B12 to the organism of the ruminant that grazes them is reduced and failure of gestation is induced. Outdoor exposure of ruminants to adverse climatic conditions by itself can increase the vitamin and trace element requirements. Adaptation of production systems taking into account these interactions between gestation and sources of stress or change of the quality of feeding stuffs as well as further developments of knowledge in that field is necessary to promote sustainable agricultural practices.
Small proline-rich proteins (SPRR) are known to construct the cornified cell envelope (CE) in the stratified squamous epithelial cell. Their functions in the simple epithelium such as the uterine epithelium are not clear hitherto. In the present study, the mRNA expression patterns of sprr2 family members in the mouse uterus and vagina during the estrous cycle and pregnancy as well as their regulation by steroids were investigated. Using semi-quantitative RT-PCR, it was revealed that the transcripts of sprr2b, 2e and 2g genes were up-regulated in the proestrous and estrous uteri, and sprr2d was up-regulated only in the estrous uterus. In the vagina, transcription of sprr2a, 2b, 2d, 2e and 2k genes were up-regulated at the metestrous stage. Northern blot analysis demonstrated that the overall expression of sprr2 was highly up-regulated in the estrous uterus and the metestrous vagina. During pregnancy, the sprr2 mRNA in the uterus was sharply repressed from day 3 postcoitus on, and began to be induced around labor time. In situ hybridization showed that the sprr2 transcripts were localized in uterine luminal and glandular epithelial cells as well as vaginal stratified epithelial cells. In ovariectomized mice, the expression of sprr2a, 2d, 2e and 2f genes in the uterus were induced by estrogen, and the effect of estrogen on sprr2d and 2e expression could be partly abolished by progesterone. The data indicate that the sprr2 genes have unique regulation patterns in different reproductive tissues under different physiological conditions, and the encoded proteins might play diverse functions in the female reproductive system.
In the organism, nutrient exchanges among tissues and organs are subject to numerous sources of physiological or nutritional variation, and the contribution of individual factors needs to be quantified before establishing general response laws.To achieve this, meta-analysis of data from publications is a useful tool.The objective of this work was to develop a bibliographic database of nutrient fluxes across organs and tissues of ruminant animals (Flora) under Access using the Merise method.The most important criteria for Flora were the ease to relate the various information, the exhaustivity and the accuracy of the data input, a complete description of the diets, taking into account the methods of the methodological procedures of measurement and analysis of blood nutrients and the traceability of the information.The conceptual data model was built in 6 parts.The first part describes the authors and source of publication, and the person in charge of data input.It clearly separates and identifies the experiments, the groups of animals and the treatments within a publication.The second part is concerned with feeds, diets and their chemical composition and nutritional value.The third and fourth parts describe the infusion of any substrates and the methods employed, respectively.The fifth part is devoted to the results of blood flows and nutrient fluxes.The sixth part gathers miscellaneous experimental information.All these parts are inter-connected.To model this database, the Merise method was utilised and 26 entities and 32 relationships were created.At the physical level, 93 tables were created, corresponding, for the majority, to entities and relationships of the data model.They were divided into reference tables (n = 65) and data tables (n = 28).Data processing was developed in Flora and included the control of the data, generic calculations of unknown data from given data, the automation of the estimation of the missing data or the chemical composition of the diets.It also included the construction of tables for meta-analyses and the study of the variations of several factors within publications (pre-coding of meta-analyses).Overall, the system was built to facilitate the gathering, input, validation, management and retrieval of data from publications.
