Isolation of Babesia divergens from carrier cattle blood using in vitro culture

Babesia divergens, the main causative agent of bovine babesiosis in Western Europe, was isolated from naturally infected cattle. Ninety-six blood samples were examined by means of an in vitro culture technique in sheep erythrocytes: 19 of them were collected from animals in the acute phase of the disease with visible parasitemia on blood smears, while the 77 remaining animals showed no microscopically detectable parasites. B. divergens was cultured from the 19 first blood samples as well as from 31 samples collected from asymptomatic animals. The time period before parasites could be detected in the culture varied in the latter samples from 6 to 20 days. The effects of sampling condition (anticoagulant used) and storage length were tested. A good correlation was obtained between immunofluorescent antibody test and culture, with identical results (positive or negative) for 89.6% of the samples collected from asymptomatic animals. The sensitivity of the in vitro culture method was determined and was about 10 parasites/mL of whole blood from three independent experiments performed with three different isolates, confirming its suitability to detect and culture diverse B. divergens isolates from carrier cattle. The parasites could indeed be isolated 9 months after the acute babesiosis phase in the blood of naturally infected animals. The 50 isolates collected in this study were successfully subcultured, cryopreserved and resuscitated using the same culture medium. The in vitro isolation of B. divergens from asymptomatic carrier cattle was achieved and will allow the analysis of parasite diversity within cattle herds.     

Thinning effect on light regime and growth of underplanted red oak and black cherry in post-agricultural forests of south-eastern Canada

New Forests - Over the last century, north-eastern North America has seen the gradual abandonment of much agricultural land that had become unsuitable for modern practices. This shift in land-use...     

Extraction, preparation and characterization of cellulose fibres and nanocrystals from rice husk

Cellulose fibres and cellulose nanocrystals were extracted from rice husk. Fibres were obtained by submitting the industrial rice crop to alkali (NaOH) and bleaching treatments. Nanocrystals were extracted from these fibres using sulphuric acid (H₂SO₄) hydrolysis treatment. The material obtained after each stage of the treatments was carefully characterized and its chemical composition was determined. Morphological investigation was performed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Fourier transform infrared (FTIR) spectroscopy showed the progressive removal of non-cellulosic constituents. X-ray diffraction (XRD) analysis revealed that the crystallinity increased with successive treatments. The thermal stability of the rice husk fibres and cellulose nanocrystals was also investigated using thermogravimetric analysis (TGA).     

Development of a platform of antibody-presenting liposomes

Antibody-presenting liposomes present high interest as drug delivery systems. The association of antibodies to liposomes is usually realized by covalent coupling of IgGs or their antigen-binding fragments to lipid polar head groups by means of hetero-bifunctional crosslinkers. We present here an original platform of IgG-presenting liposomes which is based on a fusion protein between Annexin-A5 (Anx5) and the IgG-binding ZZ repeat derived from Staphylococcus aureus protein A. The Anx5ZZ fusion protein acts as a bi-functional adaptor that anchors IgGs to liposomes in a non covalent and highly versatile manner. The interactions between IgGs, Anx5ZZ and liposomes were characterized by PAGE, dynamic light scattering and fluorescence quenching assays, establishing that binding of Anx5ZZ to IgGs and of Anx5ZZ-IgG complexes to liposomes is complete with stoichiometric amounts of each species. We found that the sequence of assembly is important and that Anx5ZZ-IgG complexes need to be formed first in solution and then adsorbed to liposomes in order to avoid aggregation. The targeting capacity of Anx5ZZ-IgG-functionalized liposomes was demonstrated by electron microscopy on an ex vivo model system of atherosclerotic plaques. This study shows that the Anx5ZZ adaptor constitutes an efficient platform for functionalizing liposomes with IgGs. This platform may present potential applications in molecular imaging and drug delivery.     

Evidence of the exploitation of marine resource by the terrestrial insect Scapteriscus didactylus through stable isotope analyzes of its cuticle

Background  

About 4 × 10⁵ eggs in more than 5000 marine turtle nests are deposited every year on a 3.6 km long beach in French Guiana (South America). The dry biomass of eggs is estimated to be 5 × 10³ kg, yet only 25% of this organic matter will return to the ocean in the form of hatchlings. Such amounts of organic matter are supposed to drive the functioning of the beach ecosystem. Previous studies have shown that egg predators and detritivorous organisms dominate the trophic relationships and the dynamics of the system. The role of a terrestrial insect Scapteriscus didactylus (Latreille), which damages up to 40% of the eggs of the marine turtle (Dermochelys coriacea), was unexpected. However it was impossible from direct observations to prove that the mole cricket consumed a significant amount of these eggs. Therefore, the precise place of the mole cricket in the nitrogen and carbon cycles of the beach ecosystem could not be determined. In order to answer this question, we looked for a marine signature of carbon and nitrogen source metabolized by the mole cricket.     

Radar soundings of the subsurface of Mars

The martian subsurface has been probed to kilometer depths by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument aboard the Mars Express orbiter. Signals penetrate the polar layered deposits, probably imaging the base of the deposits. Data from the northern lowlands of Chryse Planitia have revealed a shallowly buried quasi-circular structure about 250 kilometers in diameter that is interpreted to be an impact basin. In addition, a planar reflector associated with the basin structure may indicate the presence of a low-loss deposit that is more than 1 kilometer thick.     

Volume change of bread and bread crumb during cooling,chilling and freezing,and the impact of baking

During baking, bread dough undergoes an expansion followed by a slight contraction at the end of baking. The contraction during baking has been evidenced by some authors. However, there is a limited amount of literature about the contraction of the crumb during the chilling phase and also during the freezing phase in the case of freezing. A study has been carried out to better understand the impact of the baking degree on the contraction of the crumb during chilling after baking and during freezing. The volume of the samples has been evaluated with a laser volumeter. Breads (70 g dough) were baked until reaching 75 °C, 85 °C, 95 °C, 98 °C and then 98 °C for 10 min. Results showed that a longer baking resulted in a lower contraction of the bread. The volume change was between 25% and 2.5% for baking at 75 °C—0 min dwell and 98 °C—10 min dwell, respectively. The contraction was compared to the contraction of degassed bread crumb samples, which was more important. SEM pictures showed that the degree of baking also corresponded to a very different structure of the crumb. For the longer baking, the starch granules were fully gelatinized and no ghosts of starch granules were visible. The magnitude of the contraction was thus associated with the degree of baking and with the degree of starch granule destructuration.     

Cardinal temperatures variability within a tropical japonica rice diversity panel

Air temperature is one of the most critical climatic factors controlling rice growth, development, and production in current and future climatic scenarii predicting increasingly frequent situations of extreme and/or fluctuating temperatures. With its large spectrum of geographical origins and cropping areas, one can credit tropical japonica rice subspecies of a probable genetic diversity of its response to air temperature, which is of major interest for the breeding of better adapted rice varieties. A panel of 195 rice accessions (175 japonica plus 20 reference cultivars) was studied in controlled environment to estimate cardinal (base, optimum, and maximum) temperatures based on the monitoring of the elongation rate (LERmax) of the sixth leaf on the main stem in response to six fixed thermal treatments ranging from 16 to 35 °C. A dedicated statistical framework was elaborated for estimating LERmax, cardinal temperature and related uncertainties. Developed statistical framework enhanced the precision of cardinal temperatures estimated compared to previously reported methods, especially for base temperature. Maximum temperature was trickier to estimate and will require further studies. A significant genotypic variability for base and optimal temperature was pointed out, suggesting tropical japonica subspecies represents a relevant genetic pool to breed for rice genotypes adapted to various thermal situations. These results also suggested that using genotype-dependent cardinal temperature values should enhance the way crop growth models account for genotype?×?environment interactions hence their predictive value in current and future climatic conditions.     

Global mineralogical and aqueous mars history derived from OMEGA/Mars Express data

Global mineralogical mapping of Mars by the Observatoire pour la Mineralogie, l'Eau, les Glaces et l'Activité (OMEGA) instrument on the European Space Agency's Mars Express spacecraft provides new information on Mars' geological and climatic history. Phyllosilicates formed by aqueous alteration very early in the planet's history (the "phyllocian" era) are found in the oldest terrains; sulfates were formed in a second era (the "theiikian" era) in an acidic environment. Beginning about 3.5 billion years ago, the last era (the "siderikian") is dominated by the formation of anhydrous ferric oxides in a slow superficial weathering, without liquid water playing a major role across the planet.     

The establishment and impact of Pseudorasbora parva,an exotic fish species introduced into Lake Mikri Prespa (north-western Greece)

• 1. The topmouth gudgeon Pseudorasbora parva Schlegel, 1842, a south-east asian cyprinid, was introduced accidentally in the Danube Delta in Romania in the 1960s and has now achieved a pan-Danubian distribution. P. parva has been introduced into other countries, such as Greece, usually inadvertently included with other species imported for fish farming. In 1984–85, during a study of the fish populations of Lake Mikri Prespa (north-west Greece), several topmouth gudgeon were caught. Our aim was to study the changes in the population size of P. parva over nearly 10 years, to study its life history traits and to assess its potential impacts on native fish species.
• 2. The catch per unit effort (CPUE) in spring increased significantly between 1984 and 1992. We found evidence that P. parva has established a breeding population in the lake. P. parva combines many characteristics likely to favour a successful colonization (resistance to harsh climatic conditions, early sexual maturity, extended breeding season, broad dietary spectrum). Growth in Lake Prespa, where the oldest individuals captured were 3 years old, is very similar to that observed within its native range.
• 3. There is evidence for dietary overlap between P. parva and three endemic species: Paraphoxinus epiroticus prespensis, Cobitis meridionalis and Alburnoides bipunctatus ohridanus. No decline in the populations of these three species has yet been demonstrated. Other possible impacts are discussed. The successful colonization by P. parva was certainly favoured by the absence of a true piscivorous fish in the lake and by the isolation and high level of endemism of fish communities.
• 4. The conservation of the many endemic species in the lake should be a priority and the introduction of exotic species should be banned.