Relationship among estradiol, cortisol and intensity of estrous behavior in dairy cattle

Economic profitability of a dairy farm is based, in part, on the calving interval of the cows. The optimal interval is 365 d. To achieve this, the cow needs to be pregnant within 85 d post partum. The first and most problematic step in this process is the determination of the optimal time for insemination, which is based on estrous behavior. The expression of estrous behavior, however, is at a low level in modem dairy herds, resulting in low detection rates and longer calving intervals. In the present study, a point scale was used to monitor postpartum, nonpregnant cows for estrous symptoms. Frequent blood samples were taken around estrus, and the cows were fit with pedometers to measure their activity. Correlations between the occurrence of symptoms of estrus and levels of estradiol and cortisol were then analyzed. Standing heat, the standard symptom of estrus, was observed in only 53% of the cows. A high correlation of 0.7 was found between estradiol concentration and estrous behavior. This was empasized by the fact that the estradiol level reached its highest level of 7.76 + 2.39 (SD) pg/mL at the same time as the highest behavior score. The highest pedometer readout lagged 8 h behind this moment. Cortisol levels did not exceed the physiological levels in rest situations but showed an increase at the time estrous behavior was at its maximum. The present study showed that standing heat is not the primary symptom for detecting estrus in cows. Pedometers are a useful aid but they have to be read several times a day. The high correlation between the visual symptoms of estrus and estradiol concentrations indicates that visual estrus detection is an efficient, reliable way to determine the right time for insemination.     

Characterization of <Emphasis Type="Italic">Mycobacterium tuberculosis</Emphasis> Beijing isolates from the Mediterranean area

Background  

The Beijing lineage of Mycobacterium tuberculosis is causing concern due to its global distribution and its involvement in severe outbreaks. Studies focused on this lineage are mainly restricted to geographical settings where its prevalence is high, whereas those in other areas are scarce. In this study, we analyze Beijing isolates in the Mediterranean area, where this lineage is not prevalent and is mainly associated with immigrant cases.     

Bovine cumulus-oocyte-complex-quality is reflected in sensitivity for alpha-amanitin, oocyte-diameter and developmental capacity

The aim of the present study was to find more parameters to define developmental competence of cumulus-oocyte-complexes (COCs). Bovine COCs were divided into five groups based on their morphology. In order of increasing level of atresia: COC-A had a bright, compact cumulus investment; COC-B1 also had a compact cumulus investment, but was darker than COC-A; the color of COC-B2 was comparable with COC-B1 but the corona radiata appeared to dissociate from the rest of the cumulus investment; the cumulus of COC-B3 was almost black and the corona radiata was almost completely dissociated from the rest of the cumulus investment; COC-C had a strongly expanded cumulus investment with dark spots of degenerated cells. An increasing level of atresia was accompanied by: (1) an increasing zona pellucida diameter (147.6, 150.8, 151.0, 154.3 and 155.1 microm, respectively, for COC-A, COC-B1, COC-B2, COC-B3 and COC-C); (2) an increasing oocyte diameter except for COC-C (120.9, 122.8, 122.8, 123.9 and 118.4 microm, respectively); (3) an increasing developmental competence except for COC-C (13.9, 14.7, 17.4, 19.1 and 11.5%, respectively, development to morula and blastocyst after in vitro embryo production (IVP)) and (4) by a increasing percentage of oocytes exhibiting germinal vesicle breakdown (GVBD) after 24h culture with alpha-amanitin and FSH, except for COC-A (34.4, 68.6, 51.0, 22.0 and 4.8%, respectively, oocytes arrested in GV). In general, embryo-quality, expressed in nuclei-count, was significantly affected by COC-quality (P < 0.05) with B3 > B1> B2 > A > C. However, if the developmental stages were compared separately, this effect was less evident. It was found that, in absence of FSH, alpha-amanitin was unable to inhibit GVBD and that the success of GVBD inhibition was positively correlated to the amount of cumulus cells surrounding the oocyte. COCs that had been exposed to alpha-amanitin and FSH during maturation retained the ability to cleave after IVF, but were unable to develop any further.     

Prolactin levels and the LH-response to synthetic LH-RH in the lactating sow

To determine the role of prolactin in the suppression of ovarian activity during lactation in the sow experiments were performed to investigate a possible inhibitory action of prolactin at the pituitary level. Therefore the LH-response to an intravenous injection of 25 μg synthetic LH-RH was measured in the 1st, 2nd and 3rd week of lactation. The compound was injected under high and low concentrations of prolactin in the peripheral blood, the latter achieved by removal of the piglets 6 h before administration of LH-RH. The results showed no difference in the effect of LH-RH injected at high or low prolactin levels. However, although the mean prolactin concentrations in the 1st, 2nd and 3rd week of lactation were similar, the results clearly demonstrated an increase in LH-response as lactation proceeds.The low responsiveness of the pituitary shortly post partum was also observed when the preparturient rise of prolactin was suppressed by treatment with bromoergocryptine. Injections of LH-RH in the last week of gestation given before and after the physiological increase of PRL, which occurred about 48 h before delivery, all showed low LH-response.It is obvious from the presented data that the LH-response to an intravenous injection of 25 μg LH-RH is in no way correlated with the prolactin levels at the time of treatment.     

Marmoset phylogenetics, conservation perspectives, and evolution of the mtDNA control region

Marmosets (genus Callithrix) are a diverse group of platyrrhine primates with 13-15 purported taxa, many of them considered endangered. Morphological analyses constitute most of the basis for recognition of these forms as distinct taxa. The purpose of this study was to provide a molecular view, based on mitochondrial control region sequences, of the evolutionary history of the marmosets, concomitant with a molecular phylogenetic perspective on species diversity within the group. An additional purpose was to provide the first comparative examination of a complete New World monkey control region sequence with those of other mammals. The phylogenetic analyses provide convincing support for a split between the Atlantic forest and Amazonian marmosets, with the inclusion of the pygmy marmoset (Cebuella pygmaea) at the base of the Amazonian clade. The earliest branch of the Atlantic forest group was C. aurita. In the Amazonian group, the analyses do not support the recognition of C. humeralifer and the recently described C mauesi as distinct taxa. They do, however, support a clear distinction between C. argentata and a strongly supported mixed clade of C. humeralifer and C. mauesi. In the Atlantic forest group, the phylogenetic tree suggests mixing between C. penicillata, C. kuhli, and possibly C. jacchus. Most of the sequence features characteristic of other mammal control regions were also evident in marmosets, with the exception that conserved sequence blocks (CSBs) 2 and 3 were not clearly identifiable. Tandem repeat units often associated with heteroplasmy in a variety of other mammals were not evident in the marmoset sequences.      

Changes in protein synthesis and phosphorylation patterns during bovine oocyte maturation in vitro

Sequential protein synthesis and protein phosphorylation patterns were generated by radiolabelling bovine cumulus-oocyte complexes after various periods of culture with [35S]methionine and [32P]orthophosphate respectively. The radiolabelled oocytes were assessed for their nuclear status and used individually for gel electrophoresis. Marked changes in the protein synthesis patterns were observed exclusively after germinal vesicle breakdown (GVBD), whereas oocytes which remained in the germinal vesicle stage showed a consistent protein synthesis pattern. The changes were observed after 8 and 16 h or culture, shortly after GVBD and before first polar body extrusion. From 3 h of culture, dominant phosphoprotein bands with apparent molecular weights of 24,000 and two between 50,000 and 60,000 were observed. The latter bands displayed slight molecular weight changes, which were not closely time related. After GVBD, the phosphoprotein band with Mr 19,000 was no longer observed. This study demonstrates that specific changes in protein synthesis and protein phosphorylation are programmed during bovine oocyte maturation.     

Attenuation of pattern recognition receptor signaling is mediated by a MAP kinase kinase kinase

Pattern recognition receptors (PRRs) play a key role in plant and animal innate immunity. PRR binding of their cognate ligand triggers a signaling network and activates an immune response. Activation of PRR signaling must be controlled prior to ligand binding to prevent spurious signaling and immune activation. Flagellin perception in Arabidopsis through FLAGELLIN‐SENSITIVE 2 (FLS2) induces the activation of mitogen‐activated protein kinases (MAPKs) and immunity. However, the precise molecular mechanism that connects activated FLS2 to downstream MAPK cascades remains unknown. Here, we report the identification of a differentially phosphorylated MAP kinase kinase kinase that also interacts with FLS2. Using targeted proteomics and functional analysis, we show that MKKK7 negatively regulates flagellin‐triggered signaling and basal immunity and this requires phosphorylation of MKKK7 on specific serine residues. MKKK7 attenuates MPK6 activity and defense gene expression. Moreover, MKKK7 suppresses the reactive oxygen species burst downstream of FLS2, suggesting that MKKK7‐mediated attenuation of FLS2 signaling occurs through direct modulation of the FLS2 complex.