Antipain microinjection prevents progesterone to inhibit adenyl cyclase in Xenopus oocytes

Microinjection of antipain, an inhibitor of thiol and Ca2+-dependent proteases, in immature Xenopus oocytes inhibited meiotic maturation induced by progesterone, but not by transfer of cytoplasm taken from maturing oocytes. Oocytes could be released from antipain inhibition by increasing progesterone concentration. alpha-32P-ATP was microinjected to study adenylcyclase in ovo. As already reported, neosynthesis of cAMP was decreased following progesterone application. This decrease was not observed, or it was considerably reduced, in oocytes previously injected with antipain. In amphibian, full-grown ovarian oocytes are arrested at first meiotic prophase, and have a large nucleus known as the germinal vesicle. Progesterone induces the production of a cytoplasmic maturation-promoting factor (MPF), which itself triggers germinal vesicle breakdown (GVBD), and subsequent events of meiotic maturation (Masui and Markert, 1971; Gerhart et al., 1984). A considerable body of evidences support the view that release from prophase block is due to inactivation of a cAMP-dependent protein kinase (reviewed by Maller, 1983). On the other hand, progesterone has been shown to induce a transient decrease in cAMP level (Speaker and Butcher, 1977; Schorderet-Slatkine et al., 1982; Cicirelli et al., 1985), and this initial drop of cAMP, along with a number of studies indicating a decrease in adenylate cyclase activity (Mulner et al., 1979; Baltus et al., 1981; Sadler and Maller, 1981; Finidori-Lepicard et al., 1981; Jordana et al., 1981), provided key support to the theory that an early drop in cAMP led to the dephosphorylation of a hypothetical protein which initiates maturation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ecological preference between generalist and specialist rodents: spatial and environmental correlates of phenotypic variation

Different ecological preferences among species may result in differences in response to similar environmental variation. To test this hypothesis, we assessed the patterns of skull and mandible size and shape variation in three Sigmodontinae mice from agroecosystems of central Argentina with increasing degree of specialization: Calomys musculinus, Akodon azarae and Oxymycterus rufus. Spatial patterns in size and shape were analysed after controlling for allometry and sexual dimorphism using a total of 697 specimens. We then evaluated the covariation between shape, climatic and environmental variables and assessed the contribution of distinct climatic and environmental variables to phenotypic variability. Oxymycterus rufus displayed a marked spatial structure, and there was a high correlation between shape, climatic and environmental variables in this species. Climatic and environmental variables had a moderate effect on the phenotype of A. azarae, and were not correlated with morphological variation in C. musculinus. Our study highlights the difference in phenotypic responses to spatial and environmental gradients across coexisting species, specialist species displaying a more marked spatial structure in morphology than generalist species. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 112 , 180–203.     

MATtrack: A MATLAB-Based Quantitative Image Analysis Platform for Investigating Real-Time Photo-Converted Fluorescent Signals in Live Cells

We introduce here MATtrack, an open source MATLAB-based computational platform developed to process multi-Tiff files produced by a photo-conversion time lapse protocol for live cell fluorescent microscopy. MATtrack automatically performs a series of steps required for image processing, including extraction and import of numerical values from Multi-Tiff files, red/green image classification using gating parameters, noise filtering, background extraction, contrast stretching and temporal smoothing. MATtrack also integrates a series of algorithms for quantitative image analysis enabling the construction of mean and standard deviation images, clustering and classification of subcellular regions and injection point approximation. In addition, MATtrack features a simple user interface, which enables monitoring of Fluorescent Signal Intensity in multiple Regions of Interest, over time. The latter encapsulates a region growing method to automatically delineate the contours of Regions of Interest selected by the user, and performs background and regional Average Fluorescence Tracking, and automatic plotting. Finally, MATtrack computes convenient visualization and exploration tools including a migration map, which provides an overview of the protein intracellular trajectories and accumulation areas. In conclusion, MATtrack is an open source MATLAB-based software package tailored to facilitate the analysis and visualization of large data files derived from real-time live cell fluorescent microscopy using photoconvertible proteins. It is flexible, user friendly, compatible with Windows, Mac, and Linux, and a wide range of data acquisition software. MATtrack is freely available for download at eleceng.dit.ie/courtney/MATtrack.zip.     

A Randomised,Double-Blind,Controlled Efficacy Trial of the LiESP/QA-21 Vaccine in Na?ve Dogs Exposed to Two Leishmania infantum Transmission Seasons

Canine leishmaniasis is an important zoonosis caused by uncontrolled infection with Leishmania infantum, where an inappropriate immune response is not only responsible for permitting this intracellular parasite to multiply, but is also responsible for several of the pathological processes seen in this disease. Effective canine vaccines are therefore a highly desirable prevention tool. In this randomised, double-blinded, controlled trial, the efficacy of the LiESP/QA-21 vaccine (CaniLeish, Virbac, France) was assessed by exposing 90 naïve dogs to natural L. infantum infection during 2 consecutive transmission seasons, in two highly endemic areas of the Mediterranean basin. Regular PCR, culture, serological and clinical examinations were performed, and the infection/disease status of the dogs was classified at each examination. The vaccine was well-tolerated, and provided a significant reduction in the risk of progressing to uncontrolled active infection (p = 0.025) or symptomatic disease (p = 0.046), with an efficacy of 68.4% and a protection rate of 92.7%. The probability of becoming PCR positive was similar between groups, but the probability of returning to a PCR negative condition was higher in the vaccinated group (p = 0.04). In conclusion, we confirmed the interest of using this vaccine as part of a comprehensive control program for canine leishmaniasis, and validated the use of a protocol based on regular in-depth assessments over time to assess the efficacy of a canine leishmaniasis vaccine.     

Identification of pOENI-1 and Related Plasmids in Oenococcus oeni Strains Performing the Malolactic Fermentation in Wine

Plasmids in lactic acid bacteria occasionally confer adaptive advantages improving the growth and behaviour of their host cells. They are often associated to starter cultures used in the food industry and could be a signature of their superiority. Oenococcus oeni is the main lactic acid bacteria species encountered in wine. It performs the malolactic fermentation that occurs in most wines after alcoholic fermentation and contributes to their quality and stability. Industrial O. oeni starters may be used to better control malolactic fermentation. Starters are selected empirically by virtue of their fermentation kinetics and capacity to survive in wine. This study was initiated with the aim to determine whether O. oeni contains plasmids of technological interest. Screening of 11 starters and 33 laboratory strains revealed two closely related plasmids, named pOENI-1 (18.3-kb) and pOENI-1v2 (21.9-kb). Sequence analyses indicate that they use the theta mode of replication, carry genes of maintenance and replication and two genes possibly involved in wine adaptation encoding a predicted sulphite exporter (tauE) and a NADH:flavin oxidoreductase of the old yellow enzyme family (oye). Interestingly, pOENI-1 and pOENI-1v2 were detected only in four strains, but this included three industrial starters. PCR screenings also revealed that tauE is present in six of the 11 starters, being probably inserted in the chromosome of some strains. Microvinification assays performed using strains with and without plasmids did not disclose significant differences of survival in wine or fermentation kinetics. However, analyses of 95 wines at different phases of winemaking showed that strains carrying the plasmids or the genes tauE and oye were predominant during spontaneous malolactic fermentation. Taken together, the results revealed a family of related plasmids associated with industrial starters and indigenous strains performing spontaneous malolactic fermentation that possibly contribute to the technological performance of strains in wine.