Effect of oestrous cycle and early pregnancy on uterine production and expression of immune regulatory factors in gilts

This study was undertaken to characterize uterine immune factors involved in the establishment of pregnancy in gilts. Thirty crossbred Yorkshire-Landrace gilts of similar age and weight were observed twice a day for oestrous behaviour with intact boars. On the day of first standing oestrus (Day 0) and 12h later, 15 gilts were inseminated with pooled semen from Duroc boars of proven fertility. Pregnant gilts were slaughtered either on Days 10, 15 or 25 of gestation (n=5 per day). The other 15 gilts were not inseminated and were slaughtered on either Days 0, 10 or 15 of the oestrous cycle (n=5 per day). Immediately after slaughter, endometrial tissue samples from the mesometrial side were removed for gene expression using RNase protection assay and in situ hybridization methodologies. The other uterine horn was flushed with 20 ml of PBS to collect the uterine fluid. In pregnant gilts, endometrial interleukin (IL)-6 mRNA expression was higher on Day 15 than on Days 10 and 25 (P<0.01 and P<0.1, respectively). On Day 15, IL-6 expression was also significantly higher (P<0.01) in pregnant gilts than in cyclic gilts. In both pregnant and cyclic gilts, transforming growth factor (TGF)-beta2 in uterine fluid was significantly higher (P<0.0001) on Day 15 than on Day 10. At the gene expression level, TGF-beta2 also increased between Days 10 and 15 in both cyclic and pregnant gilts but differences were not significant. On Day 15, concentrations of interferon-gamma and prostaglandin E(2) (PGE(2)) in uterine fluid were markedly higher (P<0.001) in pregnant gilts than in cyclic gilts, whereas the total amount of TGF-beta2 in uterine fluid and its endometrial expression were approximately 70% higher although this increase was not significant. Finally, tumour-necrosis factor-alpha and granulocyte-macrophage/colony-stimulating factor mRNA expressions were undetectable in all endometrial samples. In conclusion, production and/or expression of uterine TGF-beta2, IL-6 and PGE(2) increased during the embryonic attachment period and are coincidental with embryonic interferon-gamma production.     

Sex ratios in mule duck embryos at various stages of incubation

Mule duck hatcheries have long reported varying degrees of unbalance in the sex ratio, with a preponderance of male mules at hatching. The aim of the present study was to assess the distributions of sex ratios at various stages of development in embryos originating from intra- and intergeneric crosses between parental lineages (Muscovy male x Muscovy female, Pekin male x Pekin female, Muscovy male x Pekin female or Mule, and Pekin male x Muscovy female or Hinny). In Experiment I, embryo sexing was performed on Days 1 and 5 of incubation (by multiplex PCR) and at hatching (by vent observation). The sex ratio was not significantly modified during the early stages of embryo development whatever the genetic origin (P>0.05, Days 1 and Day 5) but our results in mule and hinny ducklings confirmed the preponderance of males among normally hatched ducklings originating from the intergeneric lineage (58.9 and 55.4% males in mules and hinnies, respectively; P<0.05 in both cases). Sex ratio (vent sexing) in second grade (cull) ducklings revealed that 68% of these ducklings were females (P<0.05). In Experiment II, the distribution of sex ratio was also performed in mule duck eggs from 6 batches (400,000 eggs/batch) first examined for fertility (candling) on Day 18 of incubation. These results indicate that the percentage of males present in the population of normally hatched ducklings increases when fertility decreases. In addition, this experiment also revealed that 83.7-90.5% of viable male mule embryos develop up to hatching, compared to only 43.0-51.0% of female mule embryos. Given that a deviation in sex ratio during the first stages of incubation is unlikely (Experiment I), it is concluded that the skewed sex ratio of mule ducks at hatching is primarily due to increased late mortality in female mule embryos occurring between egg transfer and hatching. This mortality originated, at least in part, from the intergeneric origin of female mules, and was marked to a greater or lesser extent depending on the initial success of fertilization in a given batch, a possible indication that the initial quality of gametes may selectively exert its influence at the later stages of embryo development.     

Mathematical analysis of competition between sensory ganglion cells for neurotrophic factor in the skin

A model is presented of competition between sensory axons for trophic molecules (e.g. a neurotrophin such as NGF), produced in a region of skin small enough to permit their free diffusion throughout it; e.g., a touch dome, or a vibrissal follicle hair sinus. The variables specified are the number of high affinity trophic factor receptors per axon terminal and the concentration of trophic factor in the extracellular space. Previous models of this class predicted the loss of all the axons innervating the region except the one requiring least trophic factor for its maintenance, even with high rates of trophic factor production. In the present model, we have imposed upper limits to axonal growth, thereby introducing new equilibria, and we show by a global analysis using LaSalle's theorem, and also by local analysis, that several axons can then coexist if the rate of production of trophic molecules is sufficiently high.     

Surface film pressure of actin: interactions with lipids in mixed monolayers

The interactions of actin with neutral lipid films made from DLPC, and with positively charged films built from DLPC and stearylamine (SA), have been characterized by the monolayer technique. Injection of actin underneath an expanded lipid film produces an increase in the surface pressure that is consistent with a penetration of the lipid molecules by actin. This adsorption of actin to the lipid is more pronounced either with positively charged films or with Mg(2+) present in the sub-phase, suggesting that the mechanism involves an electrostatic attraction. During compression, the actin molecules are squeezed out into the sub-phase, carrying along some lipid molecules; this suggests a strong affinity of the lipids for actin. An analysis of the dilational modulus shows that when actin is found as monomers at the interface, the mixed actin-lipid film undergoes three phase changes upon compression. On the other hand, when actin is polymerized at the interface, the actin and the lipid form a rigid film for which the compressibility is mostly dominated by actin.     

Improvement of acetate production from lactose by growing Clostridium thermolacticum in mixed batch culture

AIMS: The objective of this study was to increase the acetate production by Clostridium thermolacticum growing on lactose, available as a renewable resource in the milk and whey permeate from the cheese industry. METHODS AND RESULTS: Experiments for increased acetate productivity by thermophilic anaerobes grown on lactose were carried out in batch cultures. Lactose at concentration of 30 mmol l(-1) (10 g l(-1)) was completely degraded by Cl. thermolacticum and growth rate was maximal. High concentrations of by-products, ethanol, lactate, hydrogen and carbon dioxide were generated. By using an efficient hydrogenotroph, Methanothermobacter thermoautotrophicus, in a defined thermophilic anaerobic consortium (58 degrees C) with Cl. thermolacticum and the acetogenic Moorella thermoautotrophica, the hydrogen partial pressure was dramatically lowered. As a consequence, by-products concentrations were significantly reduced and acetate production was increased. CONCLUSION: Through efficient in situ hydrogen scavenging in the consortium, the metabolic pattern was modified in favour of acetate production, at the expense of reduced by-products like ethanol. SIGNIFICANCE AND IMPACT OF THE STUDY: The use of this thermophilic anaerobic consortium opens new opportunities for the efficient valorization of lactose, the main waste from the cheese industry, and production of calcium-magnesium acetate, an environmentally friendly road de-icer.     

Extraction of correlated gene clusters from multiple genomic data by generalized kernel canonical correlation analysis

MOTIVATION: A major issue in computational biology is the reconstruction of pathways from several genomic datasets, such as expression data, protein interaction data and phylogenetic profiles. As a first step toward this goal, it is important to investigate the amount of correlation which exists between these data. RESULTS: These methods are successfully tested on their ability to recognize operons in the Escherichia coli genome, from the comparison of three datasets corresponding to functional relationships between genes in metabolic pathways, geometrical relationships along the chromosome, and co-expression relationships as observed by gene expression data.     

Slight respiratory irritation but not inflammation in mice exposed to (1-->3)-beta-D-glucan aerosols

Airway irritation effects after single and repeated inhalation exposures to aerosols of beta-glucan (grifolan) were investigated in mice. In addition, the effects on serum total immunoglobulin E (IgE) production and histopathological inflammation in the respiratory tract were studied. The beta-glucan aerosols provoked slight sensory irritation in the airways, but the response was not concentration dependent at the levels studied. Slight pulmonary irritation was observed after repeated exposures. No effect was found on the serum total IgE levels, and no signs of inflammation were seen in the airways 6 h after the final exposure. The results suggest that, irrespective of previous fungal sensitization of the animals, inhaled beta-glucan may cause symptoms of respiratory tract irritation but without apparent inflammation. Respiratory tract irritation reported after inhalation of fungi may not be entirely attributed to beta-glucan.     

Desaturase activities are depleted before and after weaning in liver microsomes of spontaneously hypertensive rats

In the present study, we have investigated the microsomal linoleic acid desaturation steps into arachidonic acid in 10- and 30-day-old spontaneously hypertensive rats (SHR), as compared to their normotensive control rats, Wistar Kyoto (WKY). Suckled by adoptive Wistar normotensive female, the SHR and WKY were fed the same diet. Our results show lower Delta 6 and Delta 5 desaturase activities (the limiting steps in the bioconversion of linoleic acid into arachidonic acid) in the young SHR, as compared to the WKY normotensive rats. The fatty acid composition of liver microsomal total lipids evidences a higher proportion of linoleic acid in SHR than in WKY, in agreement with the partially depleted desaturase activities. Such a loss of desaturase activities may be under the control of hormones involved in the regulation of SHR blood pressure.     

Fine-scale population structure and dispersal in Biomphalaria glabrata, the intermediate snail host of Schistosoma mansoni, in Venezuela

Biomphalaria glabrata is the main intermediate host of Schistosoma mansoni in America and one of the most intensely studied species of freshwater snails, yet very little is known about its population biology. Here, we used seven highly polymorphic microsatellite loci to analyse genetic diversity in the Valencia lake basin, which represents the core of the endemic area for schistosomiasis in Venezuela. Populations were sampled at short spatial scale (a few kilometres), both inside the lake and in ponds or rivers near the lake. Our results indicate that B. glabrata essentially cross-fertilizes, with little variation in selfing rates among populations. Our markers detected considerable genetic variation, with an average heterozygosity of 0.60. More diversity per population was found within than outside the lake, suggesting an influence of connectivity among populations on the levels of genetic diversity. A marked population structure was detected and lake populations were less structured than other populations. Most individuals were assigned to their population of origin using an assignment test. No strong demographic signal (e.g. bottleneck) was detected, though lake populations are likely to experience bottlenecks more frequently than the other populations analysed. Differences in gene flow therefore seem to play an important role in population differentiation and in the restoring of genetic diversity in demographically unstable populations.     

The complex relationship between soluble and insoluble tau in tauopathies revealed by efficient dephosphorylation and specific antibodies

Phosphorylated tau is deposited as insoluble inclusion bodies in the tauopathies. We have used a new efficient method to dephosphorylate tau extracted from control and tauopathy brain. In some tauopathies, including Alzheimer's disease and progressive supranuclear palsy, the pattern of insoluble tau isoforms reflected that of soluble tau. In contrast, in corticobasal degeneration, Pick's disease, and some forms of fronto-temporal dementia, specific tau isoforms were selectively sequestered into insoluble inclusion-forming tau. Therefore the overall expression of individual tau isoforms does not predict which tau isoforms are deposited in all tauopathies and different mechanisms must operate that result in the deposition of specific tau isoforms.