Electroretinographic study of the white mouse intoxicated by organophosphorus: Methylparathion,parathion, and paraoxon

Methylparathion, parathion, and paraoxon have an almost identical influence on the electrical ocular response of the white mouse: action on the photoreceptors, synaptolytic effect, and possible damage of the bipolar neurons. However, methylparathion and parathion can be differentiated from paraoxon by their immediate action on the photoreceptors, action which might result from the presence of sulfur in their molecular structure.     

On the deep origin of the depressed rings on pearl surface illustrated from Polynesian Pinctada margaritifera (Linnaeus 1758)

Among the various defects that contribute to depreciate the commercial value of pearls, the occurrence of depressed rings is the most spectacular. Through a series of structural, physical and chemical characterizations of the pearl layer, this paper reveals that the origin and initial stages of these essentially superficial defects are to be found in the earliest stages of pearl formation. The disturbance in growth of the nacreous envelopes is the physical cause of the occurrence of these depressed areas. Attention is also drawn on the unexpected relationship between these large morphological alterations of the pearl surfaces and more punctual defects primarily well visible in the strongly coloured Polynesian pearls. An understanding of the actual origin of these very negative patterns opens the way to reduce their statistical occurrence by paying attention to the grafting practice.     

Identification of a Pro-Angiogenic Potential and Cellular Uptake Mechanism of a LMW Highly Sulfated Fraction of Fucoidan from Ascophyllum nodosum

Herein we investigate the structure/function relationships of fucoidans from Ascophyllum nodosum to analyze their pro-angiogenic effect and cellular uptake in native and glycosaminoglycan-free (GAG-free) human endothelial cells (HUVECs). Fucoidans are marine sulfated polysaccharides, which act as glycosaminoglycans mimetics. We hypothesized that the size and sulfation rate of fucoidans influence their ability to induce pro-angiogenic processes independently of GAGs. We collected two fractions of fucoidans, Low and Medium Molecular Weight Fucoidan (LMWF and MMWF, respectively) by size exclusion chromatography and characterized their composition (sulfate, fucose and uronic acid) by colorimetric measurement and Raman and FT-IR spectroscopy. The high affinities of fractionated fucoidans to heparin binding proteins were confirmed by Surface Plasmon Resonance. We evidenced that LMWF has a higher pro-angiogenic (2D-angiogenesis on Matrigel) and pro-migratory (Boyden chamber) potential on HUVECs, compared to MMWF. Interestingly, in a GAG-free HUVECs model, LMWF kept a pro-angiogenic potential. Finally, to evaluate the association of LMWF-induced biological effects and its cellular uptake, we analyzed by confocal microscopy the GAGs involvement in the internalization of a fluorescent LMWF. The fluorescent LMWF was mainly internalized through HUVEC clathrin-dependent endocytosis in which GAGs were partially involved. In conclusion, a better characterization of the relationships between the fucoidan structure and its pro-angiogenic potential in GAG-free endothelial cells was required to identify an adapted fucoidan to enhance vascular repair in ischemia.     

Efficacy of copper alternatives applied as stop-sprays against Plasmopara viticola in grapevine

Journal of Plant Diseases and Protection - The six products, Armicarb, Vitisan, lime sulphur, Caso, Calce Fiocco and Ulmasud, were tested for their ability to control downy mildew (Plasmopara...     

Understanding physical clogging in drip irrigation: in situ,in-lab and numerical approaches

Dripper clogging is a major drawback of microirrigation systems that must be addressed to improve their efficiency and durability. Particle-induced clogging is first studied in situ. The experiments consist in observing in real conditions the behavior of a series of drippers fitted on an agricultural plot in the south of France. The plot is supplied from a canal with Durance River water. The latter is loaded with sediments that gradually clog drippers and filters. Water analysis reveal that physicochemical clogging prevails over biological clogging. This characterization helps in setting in-lab experiment protocol. Indeed, besides field observation of clogging, laboratory analyses of both the irrigation water and the clogging material are performed with reactive and inert clay: smectite and an illite–calcite mix. A surprising tendency is observed: Salt concentration in smectite seeded water decreases the clogging, whereas it increases agglomerate size. Computational fluid dynamic simulations are carried out to investigate the impact of particles on flow behavior. Results demonstrate that clay particles interacting with the flow govern the complex structure of the fluid velocity fields inside the dripper labyrinth channel.     

Variations in vernalization requirements among ecotypes of Festuca hallii

Plains rough fescue (Festuca hallii [Vasey] Piper) is an important forage grass species in the Northern Great Plains of Canada. Its seed is in demand for forage production and habitat restoration, but erratic seed production limits supply. A comprehensive understanding of factors influencing flowering and seed production in this species is needed. This study evaluated the morphological and phenological variation among six ecotypes of F. hallii from Saskatchewan and Manitoba. Seeds were germinated, and seedlings were grown in the field and then transplanted to a greenhouse in November. Plants not flowering in the greenhouse were vernalized under 5°C and 8-h light for 11 weeks. In a separate experiment, plants were subjected to temperature regimes of 15/5°C, 10/0°C and 5/−5°C with day-length treatments of 12 h, 8 h and a gradually changing daylength from 12 to 8 h respectively. This study demonstrated the existence of considerable variation in morphological and phenological characteristics, and in growth and vernalization requirements among ecotypes of F. hallii. Vernalization requirements were not met for the ecotype from the Moist Mixed Grassland Ecoregion when it was grown under common conditions, whereas ecotypes from other ecoregions were vernalized in at least one of the 2 years in the field experiment. Northern ecotypes tended to flower earlier after artificial vernalization treatments. Overall, 15/5 to 5/−5°C d per night temperature regimes with photoperiods between 12 and 8 h were effective in inducing flowering. The seed source of F. hallii should be regarded as an important consideration affecting its use, both for habitat restoration and for forage production.     

A high virulence and pathotype diversity of Puccinia striiformis f.sp. tritici at its centre of diversity,the Himalayan region of Pakistan

Information on the pathogen virulence profile and diversity across locations is crucial for host germplasm improvement and deployment. The rapid acquisition of virulence to host resistance by the wheat yellow/stripe rust pathogen (Puccinia striiformis f.sp. tritici: PST), makes it crucial to know about its virulence and pathotype diversity. Recent studies have shown the plausible centre of origin of the pathogen in the Himalayan region, with Pakistan being the most ancestral to all other worldwide populations. To assess the status of virulence and pathotype diversity in the Himalayan region of Pakistan, a set of 127 PST infected wheat samples from eight locations were collected, multiplied and pathotyped using a set of 36 differential lines from the world set, European and Chinese sets, and 9 Avocet Yr isolines. Virulence (Vr) was recorded to 18 out of 24 tested yellow rust resistance (Yr) genes, while a total of 53 pathotypes were detected out of 127 isolates tested. Virulence was found to the resistance genes rarely deployed in Pakistan (Vr8) or even worldwide level (Vr5), while virulence to Vilmorin 23 (Yr3+) was absent in Pakistan, which is common in Europe. None of the pathotypes was dominant across all locations, however, no clear spatial structuring was observed for the studied locations. Our results suggested a high virulence and pathotype diversity in line with the previously proposed potential role of sexual recombination in the temporal maintenance of PST in the Himalayan region of Pakistan. This information should be useful in host resistance gene improvement and deployment.     

Modelling approach for the quantitative variation of sex expression in monoecious hemp (Cannabis sativa L.)

Sex expression is of primary importance for the genetic improvement and production of monoecious hemp: masculinized phenotypes are associated with higher fungal sensitivity, and feminized phenotypes with higher seed yields. However, sex expression varies quantitatively among plants and nodes and with time. Here, we developed eight variables that characterize the sex expression in monoecious hemp to dissect its genetic determinism. The monoecy degree (MD), ranging from 1 (mostly male flowers) to 5 (mostly female flowers), was recorded for each node of 167 plants, at 6 times at 1‐week intervals. Two types of longitudinal variables were constructed: ‘synthesis’ (mean MD and percentages of nodes of each MD) and ‘structure’. The latter consisted of the parameters of a logistic curve describing MD as a function of the node position. An r‐square of 0.97 was obtained between the estimated and observed MD values, and the logistic parameters were weakly correlated with each other and with the synthesis variables. Therefore, we conclude that the present modelling approach is relevant for characterizing the sex expression in monoecious hemp.     

Effect of short heat shocks applied during grain development on wheat (Triticum aestivum L.) grain proteome

In the field, developing cereal grains are often exposed to short periods of very high temperature (>35 °C) that may dramatically affect grain yield and flour quality. Here we report on the effect of 4 h of heat shock (HS) at 38 °C applied on four consecutive days during the linear phase of storage compound accumulation on grain proteome of the winter bread wheat. At maturity the average single grain dry mass and the total quantity of nitrogen per grain were 25% and 16%, respectively lower for the HS treatment than for the control, resulting in a higher (+1.6% dm) grain protein concentration in HS grains. Individual albumin–globulin, gliadin and glutenin protein fractions from grains collected just before the HS and 1, 8, and 26 (ripeness maturity) days after the HS were quantified then analysed by 2-dimensional electrophoresis followed by MALDI-TOF and MS/MS identification. The quantity per grain of 10 gliadins and 3 low molecular weight glutenin subunit proteins were significantly affected by HS. Thirty-eight HS responsive albumin and globulin proteins were identified, including several enzymes involved in carbohydrate, redox, and lipid metabolisms. One protein was transitorily induced in response to HS. Detailed discussion of the expression of these proteins is presented.     

The Chemistry of Intercepted Clouds in Northern Arizona during the North American Monsoon Season

Cloudwater samples have been collected for the first time at a high-elevation site in the US interior Southwest. Cloud samples were collected at the summit of Mt. Elden near Flagstaff, Arizona. The samples were analyzed for pH, ionic composition, trace metals, organic carbon content, and volatile organic compounds. All of the samples showed high pH values (5.12–6.66), which appear to be the result of soil/crustal acid-neutralizing components. Ammonium and nitrate were the dominant ionic species. Organic carbon concentrations ranged from 3 to 18 mg/l. Volatile aromatic compounds (toluene, ethylbenzene, and xylenes) were detected, although they did not contribute significantly to the dissolved organic matter (<1% of dissolved organic carbon). Still, their aqueous-phase concentrations were substantially higher than equilibrium partitioning from the gas phase would suggest. Metal concentrations were high when compared to other cloud studies in remote areas. Overall, with the exception of pH, the cloud chemistry showed marked inter-event variability. The source of the variability was investigated using NOAA HYSPLIT dispersion calculations. Like the cloud composition, the air mass back trajectories differed widely from event to event, and consistently, air masses that passed over highly urbanized areas had higher trace metal, organic, and ion concentrations than more pristine air masses.