Developmental competence of bovine oocytes in maturation media supplemented with follicular fluid exosomes

The present study evaluated the role offollicular fluid exosomes on the developmental competence of bovine oocytes. Ovaries from slaughtered crossbred cattle were collected, all visible surface follicles aspirated, and culture-grade oocytes were subjected to further study. Exosomes were isolated from bovine follicular fluid by differential ultracentrifugation. A total of 358 oocytes selected for the study were randomly divided into two groups. Group I constituted 111 oocytes, in which normal maturation was carried. Group II constituted 247 oocytes, in which in vitro maturation (IVM) medium was supplemented with follicular fluid exosomes at 1 μL/100 μL IVM medium. Maturation was assessed after 24h of culture in a CO2 incubator maintained at 38.5°C in 95 per cent humidified atmosphere of 5 per cent CO2. Following IVM of oocytes for 24 h, in vitro fertilisation (IVF)was carried out by co-incubating with capacitated spermatozoa for 18 h and embryo culture was carried out subsequently. In group II oocytes supplemented with exosomes, a significantly higher maturation rate (p ≤0.01) (95.80 ±1.67 vs76.10 ± 0.95), fertilisation rate (53.68 ± 3.02vs37.85 ± 7.01) and cleavage rate (p ≤0.01) (43.66 ± 2.13vs(32.47 ± 5.23) was noticed compared to oocytes in group I without any supplementation.The present study established that supplementation of follicular fluid exosomescould improve the developmental competence of bovine oocytes

Characterization of canine intestinal microRNA expression in inflammatory bowel disease and T-cell lymphoma.

Differentiating between canine inflammatory bowel disease (IBD) and intestinal T-cell lymphoma by histopathological examination of endoscopically-derived intestinal biopsies can be challenging and involves an invasive procedure requiring specialized equipment and training. A rapid, non-invasive method of diagnosis, such as blood or faecal analysis for a conserved and stable biomarker, would be a useful adjunct or replacement. Studies on dogs and humans with various types of lymphoma have shown altered microRNA (miRNA) expression patterns in blood, faeces and tissues indicating their potential use as biomarkers of disease. The present study used residual archived endoscopically-derived, formalin-fixed, paraffin-embedded (FFPE) duodenal tissue taken from pet dogs undergoing routine investigation of gastrointestinal disease. The dogs had previously been diagnosed with either normal/minimal intestinal inflammation, severe IBD or intestinal T-cell lymphoma. Next generation sequencing with qPCR validation was used to elucidate differentially expressed miRNAs between groups. Our results show that miRNA can be extracted from archived endoscopically-derived FFPE tissues from the canine duodenum and used to differentiate normal/minimally inflamed canine duodenal tissue from severe lymphoplasmacytic IBD and T-cell lymphoma

Effects of deletion of the Streptococcus pneumoniae lipoprotein diacylglyceryl transferase gene lgt on ABC transporter function and on growth in vivo

Lipoproteins are an important class of surface associated proteins that have diverse roles and frequently are involved in the virulence of bacterial pathogens. As prolipoproteins are attached to the cell membrane by a single enzyme, prolipoprotein diacylglyceryl transferase (Lgt), deletion of the corresponding gene potentially allows the characterisation of the overall importance of lipoproteins for specific bacterial functions. We have used a Δlgt mutant strain of Streptococcus pneumoniae to investigate the effects of loss of lipoprotein attachment on cation acquisition, growth in media containing specific carbon sources, and virulence in different infection models. Immunoblots of triton X-114 extracts, flow cytometry and immuno-fluorescence microscopy confirmed the Δlgt mutant had markedly reduced lipoprotein expression on the cell surface. The Δlgt mutant had reduced growth in cation depleted medium, increased sensitivity to oxidative stress, reduced zinc uptake, and reduced intracellular levels of several cations. Doubling time of the Δlgt mutant was also increased slightly when grown in medium with glucose, raffinose and maltotriose as sole carbon sources. These multiple defects in cation and sugar ABC transporter function for the Δlgt mutant were associated with only slightly delayed growth in complete medium. However the Δlgt mutant had significantly reduced growth in blood or bronchoalveolar lavage fluid and a marked impairment in virulence in mouse models of nasopharyngeal colonisation, sepsis and pneumonia. These data suggest that for S. pneumoniae loss of surface localisation of lipoproteins has widespread effects on ABC transporter functions that collectively prevent the Δlgt mutant from establishing invasive infection

Two Novel Point Mutations in Clinical Staphylococcus aureus Reduce Linezolid Susceptibility and Switch on the Stringent Response to Promote Persistent Infection

Staphylococcus aureus frequently invades the human bloodstream, leading to life threatening bacteremia and often secondary foci of infection. Failure of antibiotic therapy to eradicate infection is frequently described; in some cases associated with altered S. aureus antimicrobial resistance or the small colony variant (SCV) phenotype. Newer antimicrobials, such as linezolid, remain the last available therapy for some patients with multi-resistant S. aureus infections. Using comparative and functional genomics we investigated the molecular determinants of resistance and SCV formation in sequential S. aureus isolates from a patient who had a persistent and recurrent S. aureus infection, after failed therapy with multiple antimicrobials, including linezolid. Two point mutations in key staphylococcal genes dramatically affected clinical behaviour of the bacterium, altering virulence and antimicrobial resistance. Most strikingly, a single nucleotide substitution in relA (SACOL1689) reduced RelA hydrolase activity and caused accumulation of the intracellular signalling molecule guanosine 3′, 5′-bis(diphosphate) (ppGpp) and permanent activation of the stringent response, which has not previously been reported in S. aureus. Using the clinical isolate and a defined mutant with an identical relA mutation, we demonstrate for the first time the impact of an active stringent response in S. aureus, which was associated with reduced growth, and attenuated virulence in the Galleria mellonella model. In addition, a mutation in rlmN (SACOL1230), encoding a ribosomal methyltransferase that methylates 23S rRNA at position A2503, caused a reduction in linezolid susceptibility. These results reinforce the exquisite adaptability of S. aureus and show how subtle molecular changes cause major alterations in bacterial behaviour, as well as highlighting potential weaknesses of current antibiotic treatment regimens

A Study of the Role of the Parameterization of Heterogeneous Ice Nucleation for the Modeling of Microphysics and Precipitation of a Convective Cloud

International audienc

Ecological compensation of stochastic wetland biodiversity : National or regional policy schemes?

The aim of this study is to compare policy schemes for ecological compensation applied at national and regional levels, using exploited inland wetlands as an example. We study whether uncertainty, due to natural variability and measurement difficulties, motivates compensation that is carried out in the same region as that of the exploited site, or whether it rather motivates nationwide compensation schemes. For this purpose, we develop an empirical, chance-constrained programming model of cost-effective wetland management. The model is spatially differentiated and accounts for heterogeneity in wetland quality across wetland types and regions. Wetland quality is defined by three alternative biodiversity indices: species richness, population-weighted species richness, and red-listed species richness, estimated from voluntarily reported data on breeding bird species observations. Results show that regional schemes are more expensive, in particular if the policy maker dislikes uncertainty and wants to prioritize uncommon species. Contrary to expectations from the theoretical analysis, regional schemes would lead to a higher risk-adjusted level of biodiversity at the national level. However, regionalization also implies that targets cannot be achieved if a high safety margin is imposed. Trading ratios are robust to the choice of wetland quality index