Characterization of key genes of the renin-angiotensin system in mature feline adipocytes and during in vitro adipogenesis.

Obesity is a growing health problem in humans as well as companion animals. In the development and progression of obesity-associated diseases, the members of the renin-angiotensin system (RAS) are proposed to be involved. Particularly, the prevalence of type 2 diabetes mellitus in cats has increased enormously which is often been linked to obesity as well as to RAS. So far, reports about the expression of a local RAS in cat adipocytes are missing. Therefore, we investigated the mRNA expression of various RAS genes as well as the adipocyte marker genes adiponectin, leptin and PPAR-γ in feline adipocytes using quantitative PCR. To characterize the gene expression during adipogenesis, feline pre-adipocytes were differentiated into adipocytes in a primary cell culture and the expression of RAS key genes measured. All major RAS components were expressed in feline cells, but obvious differences in the expression between pre-adipocytes and the various differentiation stages were found. Interestingly, the two enzymes ACE and ACE2 showed an opposite expression course. In addition to the in vitro experiments, mature adipocytes were isolated from subcutaneous and visceral adipose tissue. Significant differences between both fat depots were found for ACE as well as AT1 receptor with greater expression in subcutaneous than in visceral adipocytes. Visceral adipocytes had significantly higher adiponectin and PPAR-γ mRNA level compared to the subcutaneous fat cells. Concerning the nutritional status, a significant lower expression of ACE2 was measured in subcutaneous adipocytes of overweight cats. In summary, the results show the existence of a potentially functional local RAS in feline adipose tissue which is differentially regulated during adipogenesis and dependent on the fat tissue depot and nutritional status. These findings are relevant for understanding the development of obesity-associated diseases in cats such as diabetes mellitus.

Identification of miRNAs in Bovine Endometrium through RNAseq and Prediction of Regulated Pathways.

Detection of miRNAs in reproductive tissues is a key step to understand their role in fertility. We hypothesize that miRNAs must be involved in pathways controlling endometrial physiology and defense against pathogens. In this study, we aimed to characterize miRNAs present in bovine endometrium and to predict regulated pathways. Cytobrush endometrial samples from four cows were collected at oestrous cycle days 1-5, 6-12, 13-18 and 19-21. RNA was extracted and sequenced using Ion Torrent (®) technology. After mapping of the reads to miRNA stem loops, rRNAs and tRNAs, data were normalized and analysed using DESeq2. Targets and pathways were predicted with miRmap and KEGG, respectively. Validation of miRNAs in tissue was done by RT-qPCR (miR-Q). A total of 221 identities were common among groups, accumulating more than 99% of miRNA expression. MiRNAs were predicted to regulate MAPK signalling pathway, lysosome and extracellular matrix (ECM)-receptor interaction. Eight miRNAs were validated by miR-Q, showing that let-7a-5p and let-7b were regulated across the oestrous cycle. This study demonstrated a high similarity in miRNA expression profile across the oestrous cycles in bovine endometrium. These miRNAs were predicted to regulate pathways involved in cell proliferation, differentiation, transport and catabolism. The number of pathways shared by different miRNAs indicates the broad range of regulation these molecules exhibit in the endometrium.

Characterization of the native C-reactive protein (cCRP) and the corresponding liver mRNA in dogs.

C-reactive protein (CRP) plays an important role in the acute phase reaction in humans and dogs. For the canine CRP (cCRP) only an in silico deduced preliminary transcript and amino acid sequence is available. The objective of this study was to further characterize the native cCRP protein and its corresponding liver mRNA. Furthermore, immunological similarities of serum CRP in related animal species were investigated. Native cCRP protein was isolated from dog-sera by affinity chromatography and further analyzed by immunodetection, protein sequencing (mass spectrometry and N-terminal Edman sequencing), 2D-gel electrophoresis, and glycoprotein analysis. Furthermore, cCRP cDNA sequence was determined from dog liver total RNA by RT-PCR. Gel electrophoresis, immunodetection and glycoprotein detection revealed two cCRP isotypes with different molecular weights (22 and 25kDa) with the upper band being glycosylated. Selective glycoprotein analysis showed sialic acid terminally linked (2-6) to galactose or N-acetylgalactosamine and subsequent PNGase F treatment identified N-terminal linkage. Mass spectrometry confirmed approximately 45% of the cCRP predicted amino acid sequence and N-terminal amino acid sequencing revealed a shorter native cCRP than expected (204 amino acids). The new canine CRP mRNA sequence confirms 100% of the formerly deduced sequence. Immunological homologies to the canine CRP protein were found in selected dog-related species. This study contributes major molecular details to the knowledge about canine CRP. Such structural information may assist in developing new diagnostic tools for inflammatory-based diseases in dogs as well as other dog-related species.

Quantification of ZP1, ZP2 and ZP3 mRNA of marmoset monkey (Callithrix jacchus) oocytes from periantral and antral follicles.

In mammals, the oocyte and preimplantation embryo are protected by the zona pellucida (ZP) consisting mainly of ZP glycoproteins, which are responsible for sperm binding, induction of the acrosome reaction and zona pellucida hardening to prevent polyspermia. The ZP proteins become increasingly important as possible predictors for in vitro cultured oocytes competence. As little is known about the stage-dependent expression of ZP1, ZP2 and ZP3 in marmoset monkey (Callithrix jacchus) oocytes, mRNA expression was investigated with real-time RT-PCR. Total-RNA was isolated from three different classes of marmoset oocytes; Class 1 oocytes from periantral follicles (<600 µm, n = 10), Class 2 oocytes from small antral follicles (600-1000 µm, n = 10) and Class 3 oocytes from large antral follicles (>1000 µm, n = 9). Compared with Class 1 oocytes mRNA expression of ZP1, ZP2 and ZP3 in Class 2 oocytes was significantly decreased. In Class 3 oocytes, the transcription of ZP1, ZP2 and ZP3 genes showed also a significant decrease compared with Class 1 oocytes. In this study a differently regulated expression of the ZP genes during late folliculogenesis with an obvious downregulation of ZP1, ZP2 and ZP3 could be demonstrated for the first time in the marmoset monkey.

Endometrial expression of selected transcripts involved in prostaglandin synthesis in cows with endometritis.

Several cytokines and prostaglandins play an important role in preparing the endometrium for implantation and mediating pro-inflammatory events. The aim of the present study was to examine mRNA expression of interleukin 1alpha (IL-1alpha), interleukin receptor antagonist (IL-1-RN), cytosolic prostaglandin E synthase (cPGES), microsomal PGES (mPGES-1 and mPGES-2) and lipocalin-type PGDS (L-PGDS) in the bovine endometrium. Endometrial epithelium samples were collected ex vivo from cows with different status of health at day 21-27 postpartum on a dairy farm. Three groups (n=9 animals each) were defined: (1) healthy cows with no signs of endometritis (control group), (2) cows with subclinical endometritis, and (3) cows with signs of clinical endometritis. Oestrous cycle-dependent mRNA expression pattern was investigated using bovine endometrial epithelial cells from healthy uteri collected at the abattoir. These uteri were classified into post-ovulatory, early-to-mid luteal, late luteal or pre-ovulatory phase (n=8 animals for each cycle phase). After collecting endometrial epithelium using the cytobrush-method, mRNA analysis was performed by real-time RT-PCR. L-PGDS, IL-1alpha and IL-1-RN mRNA were expressed significantly higher (P<0.05) in the endometrium of cows with subclinical or clinical endometritis compared with healthy cows. A twofold lower cPGES mRNA expression (P<0.05) was detected in cows with subclinical endometritis compared to healthy cows. L-PGDS and IL-1-RN mRNA expression was increased (P<0.05) after ovulation compared with the pre-ovulatory or luteal phase, respectively. These results support the hypothesis that a dys-regulated cytokine and/or prostaglandin profile in the uterus could be induced by subclinical endometritis or clinical endometritis.

Establishment and characterization of an adherent pure epithelial cell line derived from the bovine oviduct.

The oviduct in vivo has to perform various tasks: maturation and transport of the gametes, milieu preparation for fertilization and embryonic development, and transport of the embryo. The complex arrangement of endocrine and paracrine signals being exchanged between the early embryo and the inner cell layers of the oviduct is barely understood. Therefore, a reproducible, well-characterized oviduct epithelial cell line as well as an optimized transfection protocol for DNA vectors and siRNA for this cell line has been established. A bovine oviduct primary cell culture system has been optimized using a selection medium permitting the survival of only epithelial cells. From this we established an adherent bovine oviduct pure epithelial cell line (aBOPEC-1). This cell line maintains some important characteristics of the primary cells such as the expression of estrogen receptors and p450 aromatase but it lacks some characteristics due to the selection and dedifferentiation processes (cilia, expression of progesterone receptor and oviduct specific glycoprotein-1). Optimization of the transfection protocols finally revealed a suitable DNA-transfection procedure yielding transfection efficiencies of over 50%. Additionally, siRNA transfection efficiency reached more than 90%. This new cell line builds an essential basis especially for future functional studies in the oviduct epithelium using distinct knock down experiments.

Measurement of equine myeloperoxidase (MPO) activity in synovial fluid by a modified MPO assay and evaluation of joint diseases - an initial case study.

The aim of this study was to develop a specific myeloperoxidase (MPO) activity assay in the synovial fluid of horses and investigate whether MPO activity is increased in different forms of joint diseases. Synovial fluid samples were taken from affected joints from horses with osteoarthritis, chronic non-septic arthritis and septic arthritis, and from healthy control horses. MPO activity was measured using a specific modified o-dianisidine-assay containing 4-aminobenzoic acid hydrazide as a potent and specific inhibitor of the MPO. This assay is characterized by high reproducibility. The results reveal only a slight elevation of MPO activity in the synovial fluid of horses with osteoarthritis and chronic non-septic arthritis. However, in the cases of septic arthritis a significant increase in MPO activity was found when compared to the controls. In conclusion the first field study suggests that synovial fluid MPO may be used as a marker for septic arthritis in horses.

Determination of MMP-2 and -9 activities in synovial fluid of horses with osteoarthritic and arthritic joint diseases using gelatin zymography and immunocapture activity assays.

REASON FOR PERFORMING STUDY: Matrix metalloproteinases (MMPs)-2 and -9 activities have been found elevated in synovial fluid from various joint diseases in man. However, in the horse few data are available. OBJECTIVES: To explore the clinical significance of MMP-2 and -9 activities in synovial fluid of horses with different forms of joint diseases. METHODS: Gelatin zymography and MMP-2 and -9 immunocapture activity assays were applied on synovial fluids from control joints and joints with aseptic joint disease (AJD) and septic arthritis (SA). Additionally, MMP-2 and -9 activities were measured in samples from SA to monitor the disease process. RESULTS: Zymographic analysis revealed that samples from AJD and SA contained significantly increased latent MMP-2 activity compared to controls. Samples from SA showed significantly increased monomeric latent MMP-9 activity compared with all other affected joints and controls. Trace amounts of MMP-9 activity, due to the active and dimer form, were detected in samples from SA; however, these bands were absent in samples from AJD and controls. Using immunocapture activity assays, MMP-2 and -9 activities were found to be significantly elevated in joints from SA compared to controls and AJD samples. MMP-2 activity in samples from AJD was significantly increased compared to controls. Both MMP activities decreased in the joints from SA in the course of successful therapy. CONCLUSIONS: Data from zymographic analysis confirmed that MMP-2 and -9 were elevated in equine joint diseases. Immunocapture activity assays have been shown to be suitable for the quantitative determination of MMP-2 and -9 activities in synovial fluid of horses. Both MMP-2 and -9 activities seem to be useful to indicate SA, and MMP-2 activity might be a suitable marker for AJD. POTENTIAL RELEVANCE: These findings encourage the potential use of MMP-2 and -9 as additional aids to clinical investigation. Further work is required to validate the clinical significance of MMP activities in the progress of different joint diseases in horses.

Different inflammatory responses of bovine oviductal epithelial cells in vitro to bacterial species with distinct pathogenicity characteristics and passage number.

The bovine oviduct provides the site for fertilization and early embryonic development. Modifications to this physiological environment, for instance the presence of pathogenic bacterial species, could diminish reproductive success at early stages of pregnancy. The aim of this study was to elucidate the inflammatory responses of bovine oviductal epithelial cells (BOEC) to a pathogenic bacterial species (Trueperella pyogenes) and a potentially pathogenic bacterium (Bacillus pumilus). BOEC from four healthy animals were isolated, cultured in passage 0 (P0) and passaged until P3. Trypan blue staining determined BOEC viability during 24 h co-culture with different multiplicities of infection (MOI) of T. pyogenes (MOI 0.01, 0.05, 0.1 and 1) or B. pumilus (MOI 1 and 10). BOEC remained viable when co-cultured with T. pyogenes at MOI 0.01 and with B. pumilus at MOI 1 and 10. Extracted total RNA from control and bacteria co-cultured samples was subjected to reverse transcription-quantitative polymerase chain reaction (RTq-PCR) to determine mRNA expression of various studied genes. The rate of release of interleukin 8 (IL8) and prostaglandin E2 (PGE2) from BOEC was measured by ELISA after 24 h co-culture with bacteria. RT-qPCR of various selected pro-inflammatory factors revealed similar mRNA expression of pro-inflammatory factors in BOEC co-cultured with T. pyogenes and in the controls. Higher mRNA expression of IL 1A, -1B, tumor necrosis factor alpha and CXC ligand (CXCL) 1/2, -3, -5 and IL8 and PG synthesis enzymes in BOEC co-cultured with B. pumilus was observed. In the presence of B. pumilus a higher amount of IL8 and PGE2 was released from BOEC than from controls. The viability and pro-inflammatory response of P3 BOEC incubated with bacteria was lower than in P0 BOEC. These findings illustrate the pathogenicity of T. pyogenes towards BOEC in detail and the potential role of B. pumilus in generating inflammation in oviductal cells. Culturing conditions influenced the pro-inflammatory responses of BOEC towards bacteria. Therefore, researchers conducting epithelial-bacterial in vitro co-culture should not underestimate the effects of these parameters.

Influence of intrauterine administration of Lactobacillus buchneri on reproductive performance and pro-inflammatory endometrial mRNA expression of cows with subclinical endometritis.

Potential beneficial effects of lactic acid bacteria on the genital health of cows become of particular interest when considering the importance of an optimal uterine health status for the success of breeding in dairy farming. Therefore, the aim of the present study was to analyse the influence of an intrauterine administration of the Lactobacillus buchneri DSM 32407 on reproductive performance, uterine health status, endometrial mRNA expression of pro-inflammatory factors of cows with signs of subclinical endometritis (SCE). L. buchneri DSM 32407 (n = 56; [LAC]) or a placebo (n = 60; [PLA]) was administered on day 24-30 postpartum. Endometrial cytobrush samples of cows with SCE were taken before the administration and at three following weeks (n = 16 cows each for LAC/SCE and PLA/SCE). A higher proportion of cows of the LAC and LAC/SCE group was pregnant after the first service and median days to conception for cows pregnant on day 200 pp were shorter. Three weeks after the administration, the endometrial mRNA expression of CXCL1/2, CXCL3, CXCR2, IL1B, IL8 and PTPRC was lower in the LAC/SCE group compared with the PLA/SCE group. These findings suggest that the presence of L. buchneri DSM 32407 contributes to a uterine environment that results in a better reproductive performance.

In silico cytotoxicity assessment on cultured rat intestinal cells deduced from cellular impedance measurements.

Early and reliable identification of chemical toxicity is of utmost importance. At the same time, reduction of animal testing is paramount. Therefore, methods that improve the interpretability and usability of in vitro assays are essential. xCELLigence's real-time cell analyzer (RTCA) provides a novel, fast and cost effective in vitro method to probe compound toxicity. We developed a simple mathematical framework for the qualitative and quantitative assessment of toxicity for RTCA measurements. Compound toxicity, in terms of its 50% inhibitory concentration IC50 on cell growth, and parameters related to cell turnover were estimated on cultured IEC-6 cells exposed to 10 chemicals at varying concentrations. Our method estimated IC50 values of 113.05, 7.16, 28.69 and 725.15 µM for the apparently toxic compounds 2-acetylamino-fluorene, aflatoxin B1, benzo-[a]-pyrene and chloramphenicol in the tested cell line, in agreement with literature knowledge. IC50 values of all apparent in vivo non-toxic compounds were estimated to be non-toxic by our method. Corresponding estimates from RTCA's in-built model gave false positive (toxicity) predictions in 5/10 cases. Taken together, our proposed method reduces false positive predictions and reliably identifies chemical toxicity based on impedance measurements. The source code for the developed method including instructions is available at https://git.zib.de/bzfgupta/toxfit/tree/master.

Region-specific expression of nitric oxide synthases in the bovine oviduct during the oestrous cycle and in vitro.

Nitric oxide synthases (NOS) account for the endogenous production of nitric oxide (NO), a small and permeable bioreactive molecule. NO is known to act as a paracrine mediator during various processes associated with female reproduction. In the present study, the mRNA expression of the endothelial (eNOS) and inducible (iNOS) NO synthases were examined in bovine oviduct epithelial cells (BOEC) during the oestrous cycle. In addition, eNOS and iNOS mRNA and protein were localised by in situ hybridisation and immunocytochemistry respectively. Furthermore, the effects of exogenously applied oestradiol-17beta and progesterone on NOS mRNA regulation were studied in a suspension culture of BOEC. The eNOS mRNA abundance was low around ovulation (day 0) and increased significantly until pro-oestrus (day 18) in the ampulla. Immunoreactive protein of eNOS was detected predominantly in endothelial cells as well as in secretory oviduct epithelial cells at pro-oestrus. The iNOS mRNA concentration was significantly reduced in the isthmus at pro-oestrus (day 18) and oestrus (day 0) compared with persistently high levels in the ampulla. By in situ hybridisation, specific iNOS transcripts were additionally demonstrated in the oviduct epithelium. Immunoreactive iNOS protein was localised in secretory epithelial cells as well as in the lamina muscularis. The in vitro stimulation showed that both NOS were stimulated by progesterone, but not by oestradiol-17beta. The region-specific modulated expression of eNOS and iNOS provides evidence for an involvement of endogenously produced NO in the regulation of oviductal functions.

Increased mRNA expression of selected antimicrobial peptides around ovulation and during inflammatory processes in the bovine endometrium postpartum.

In the uterus, the first pathogen confrontations take place at the luminal endometrial epithelium. Therefore, it is required that these cells have the potential to recognize and respond to a bacterial infection. Antimicrobial peptides (AMP), part of the innate immune system in addition to cytokines, are principal effector molecules of mucosal immunity against pathogens. One important family of AMP that can permeabilize bacterial membranes is the beta-defensin (DEFB) family, which includes the following members: DEFB1, DEFB4A, and DEFB5, lingual AMP, and tracheal AMP. The bactericidal/permeability-increasing protein is also a cationic AMP that results in the death of bacteria. Another AMP family is the S100 calcium-binding protein (S100A) family including the following members: S100A8, S100A9, S100A11, and S100A12. These AMP exert their antimicrobial action through chelation of several ions. The aim of the present study was to evaluate mRNA expression patterns of selected AMP in bovine endometrial cells collected (1) at different stages of the estrous cycle (postovulatory, early-to-mid luteal, late luteal, and pre-ovulatory phase); (2) during the puerperium depending on uterine health status (healthy, subclinical, or clinical endometritis) starting on Day 24 to 30 postpartum for 3 weeks on a weekly basis; and (3) in vitro after co-culturing with Bacillus pumilus at three different multiplicities of infection (MOI 1, 5, and 10) up to 6 hours. The results reported that the mRNA expression of all candidate AMP, except DEFB1, S100A8, and S100A9, was estrous cycle dependent. In particular, around the time of ovulation, the transcription level of most AMP was higher (P < 0.05) compared with the luteal phase. Almost all candidate AMP mRNA expression was dependent on uterine health status, with a higher transcription level (P < 0.05) in inflamed endometrial tissues, especially during the late stage of the puerperium (Day 45-51 postpartum). Members of the DEFB family were nearly unaffected in their mRNA expression in primary endometrial cells co-incubated with B. pumilus. However, S100A8 and S100A9 mRNA contents were higher after 4 and 6 hours of co-incubation with B. pumilus compared with untreated controls. In conclusion, higher mRNA expression of the candidate AMP around ovulation or in inflamed endometrial tissue during the puerperium suggests their crucial role in uterine innate immunity in the defense against invading bacteria.

Gene expression profiling of bovine endometrium during the oestrous cycle: detection of molecular pathways involved in functional changes.

The endometrium plays a central role among the reproductive tissues in the context of early embryo-maternal communication and pregnancy. It undergoes typical changes during the sexual/oestrous cycle, which are regulated by the ovarian hormones progesterone and oestrogen. To identify the underlying molecular mechanisms we have performed the first holistic screen of transcriptome changes in bovine intercaruncular endometrium at two stages of the cycle--end of day 0 (late oestrus, low progesterone) and day 12 (dioestrus, high progesterone). A combination of subtracted cDNA libraries and cDNA array hybridisation revealed 133 genes showing at least a 2-fold change of their mRNA abundance, 65 with higher levels at oestrus and 68 at dioestrus. Interestingly, genes were identified which showed differential expression between different uterine sections as well. The most prominent example was the UTMP (uterine milk protein) mRNA, which was markedly upregulated in the cranial part of the ipsilateral uterine horn at oestrus. A Gene Ontology classification of the genes with known function characterised the oestrus time by elevated expression of genes, for example related to cell adhesion, cell motility and extracellular matrix and the dioestrus time by higher expression of mRNAs encoding for a variety of enzymes and transport proteins, in particular ion channels. Searching in pathway databases and literature data-mining revealed physiological processes and signalling cascades, e.g. the transforming growth factor-beta signalling pathway and retinoic acid signalling, which are potentially involved in the regulation of changes of the endometrium during the oestrous cycle.

Puerperal influence of bovine uterine health status on the mRNA expression of pro-inflammatory factors.

After parturition, uterine bacterial infections lead to inflammatory processes such as subclinical/clinical endometritis with high prevalence in dairy cows. Endometrial epithelial cells participate in this immune response with the production of pro-inflammatory factors. The objective of the present study was to evaluate the endometrial mRNA expression pattern of pro-inflammatory factors during a selected postpartum (pp) period. Dairy cows with three different uterine health conditions on days 24-30 pp (healthy: n = 11, subclinical endometritis: n = 10, clinical endometritis: n = 10) were sampled using the cytobrush technique. Subsequently, each cow was sampled 3 more times in weekly intervals (days 31-37 pp; days 38-44 pp; days 45-51 pp). Samples were subjected to mRNA analysis performed by RT-qPCR. Additionally, an analysis of cultivable bacteria was performed at the early/late stage of the selected puerperal period. mRNA expression of 16 candidate genes was analyzed by using two different approaches. The first approach referred to the initial grouping on days 24-30 pp to reveal long-term effects of the uterine health on the subsequent puerperal period. The second approach considered the current uterine health status at each sampling to elucidate the impact of different points in time. Long-term effects seem to appear for chemokines, prostacyclin synthase and prostaglandin D2 synthase. If related to the current uterine health, the majority of candidate genes were significantly higher expressed in endometritic cows on days 45-51 pp in contrast to earlier stages of the puerperium. Microbiological analysis revealed the significantly higher prevalence of Trueperella pyogenes findings in cows with clinical endometritis on days 24-30 pp, but no correlations were found on days 45-51 pp. In conclusion, a strong immune response to subclinical/clinical endometritis in the late puerperium may be related to the negative impact of these conditions on reproductive performance in dairy cows.

Impact of high dietary zinc on zinc accumulation, enzyme activity and proteomic profiles in the pancreas of piglets.

The exocrine pancreas plays an important role in zinc homeostasis. Feeding very high (2000-3000mgzinc/kg diet) levels of zinc oxide to piglets for short periods is a common practice in the swine industry to improve performance and prevent diseases. The impact on pancreatic function and possible side effects during long-term feeding of high dietary zinc levels are still poorly understood. A total of 54 weaned piglets were either fed with low (57mg/kg, LZn), normal (164mg/kg, NZn) or high (2425mg/kg, HZn) zinc concentration in the diets. After 4 weeks of feeding, ten piglets per treatment were euthanized and pancreas samples were taken. Tissue zinc concentration and metallothionein abundance was greater with HZn compared with NZn and LZn (P<0.05). Similarly, activity of α-amylase, lipase, trypsin and chymotrypsin was higher with HZn as compared with NZn and LZn diets (P<0.05), whereas elastase activity was unchanged. Total trolox equivalent antioxidative capacity of pancreas tissue was higher with HZn diets compared with the other treatments (P<0.05). Pancreatic protein profiles of NZn and HZn fed piglets were obtained by 2D-DIGE technique and revealed 15 differentially expressed proteins out of 2100 detected spots (P<0.05). The differentially expressed proteins aldose reductase, eukaryotic elongation factor II and peroxiredoxin III were confirmed by immunoblotting. Identified proteins include zinc finger-containing transcription factors and proteins mainly associated with oxidative stress response and signal transduction in HZn compared with NZn pigs. Histologic examination however showed no morphologic changes. The results suggest that long-term supply of very high dietary zinc increases zinc and metallothionein concentration, and digestive enzyme activity, but also triggers oxidative stress reactions in the pancreas of young pigs. The data provide new insights into pancreatic function under outbalanced zinc homeostasis.

Characterization and localization of beta2-adrenergic receptors in the bovine oviduct: indication for progesterone-mediated expression.

Beta2-adrenergic receptors were detected in bovine oviductal epithelium by use of receptor binding studies and expression analysis. Complementary DNA cloning gave use to the first full-length bovine beta2-adrenoceptor messenger RNA sequence (2030 bases). Receptor bioactivity in oviduct epithelial cells was characterized by specific ligand interaction and consequent cAMP generation. Expression studies demonstrated an estrous cycle-dependent regulation, with higher transcript levels and significantly increased binding capacity during the luteal phase. After progesterone supplementation, oviduct epithelial cells showed elevated receptor expression in culture, supporting the hypothesis that progesterone up-regulates the beta2-adrenergic receptor within these cells. It seems likely that catecholamines from the circulation or from innervation might be able to influence reproductive success by regulating oviductal secretion.

Demonstration of mRNAs for oxytocin and prolactin in porcine granulosa and luteal cells. Effects of these hormones on progesterone secretion in vitro.

The relative levels of mRNAs for relaxin, prolactin, inhibin and oxytocin have been measured in porcine granulosa as well as luteal cells by hybridisation to single-stranded synthetic DNA. The likelihood of a paracrine function of oxytocin and prolactin in the porcine ovary was inferred from the in vitro effects of both hormones on progesterone secretion of ovarian cells. Both hormones were found to inhibit progesterone secretion of luteal cells. In contrast, only prolactin but not oxytocin stimulated progesterone secretion in granulosa cells.

Bovine seminal plasma aSFP: localization of disulfide bridges and detection of three different isoelectric forms.

Acidic seminal fluid protein (aSFP) is a major 13 kDa protein isolated from bull seminal plasma and characterized as a new growth factor which stimulates in vitro cell division and progesterone secretion by ovarian cells. Here, we establish that the four cysteines of oxidized aSFP form two disulfide bridges between nearest-neighbour residues. This pattern is conserved in boar spermadhesins, with which aSFP shares up to 50% amino acid sequence identity, and other proteins of the recently identified CUB domain family. Using isoelectric focusing in combination with sulfhydryl group-specific blotting, the three forms of aSFP were identified as completely oxidized (pI 4.7), partly reduced (pI 4.8) and fully reduced at pI 5.1. These results indicate that native aSFP possesses two pairs of cysteine residues of different reactivity. The observation that aSFP can protect sperm from oxidative damage might be explained by its reduction/oxidation behaviour.

Monitoring gene expression changes in bovine oviduct epithelial cells during the oestrous cycle.

The oviduct epithelium undergoes marked morphological and functional changes during the oestrous cycle. To study these changes at the level of the transcriptome we did a systematic gene expression analysis of bovine oviduct epithelial cells at oestrus and dioestrus using a combination of subtracted cDNA libraries and cDNA array hybridisation. A total of 3072 cDNA clones of two subtracted libraries were analysed by array hybridisation with cDNA probes derived from six cyclic heifers, three of them slaughtered at oestrus and three at dioestrus. Sequencing of cDNAs showing significant differences in their expression levels revealed 77 different cDNAs. Thirty-seven were expressed at a higher level at oestrus, for the other 40 genes expression levels were higher at dioestrus. The identified genes represented a variety of functional classes. During oestrus especially genes involved in the regulation of protein secretion and protein modification, and mRNAs of secreted proteins, were up-regulated, whereas during dioestrus particularly transcripts of genes involved in transcription regulation showed a slight up-regulation. The concentrations of seven selected transcripts were quantified by real-time RT-PCR to validate the cDNA array hybridisation data. For all seven transcripts, RT-PCR results were in excellent correlation (r>0.92) with the results obtained by array hybridisation. Our study is the first to analyse changes in gene expression profiles of bovine oviduct epithelial cells during different stages of the oestrous cycle, providing a starting point for the clarification of the key transcriptome changes in these cells.