Isolation and characterization of ACC deaminase-producing fluorescent pseudomonads, to alleviate salinity stress on canola (Brassica napus L.) growth

Salinity stress is of great importance in arid and semi-arid areas of the world due to its impact in reducing crop yield. Under salinity stress, the amount of 1-aminocyclopropane-1-carboxylate (ACC), a precursor for ethylene production in plants, increases. Here, we conducted research under the hypothesis that isolated ACC deaminase-producing Pseudomonas fluorescens and Pseudomonas putida can alleviate the stressful effects of salinity on canola (Brassica napus L.) growth. The experiments were conducted in the Soil and Water Research Institute, Tehran, Iran. Seven experimental stages were conducted to isolate and characterize ACC deaminase-producing Pseudomonas fluorescens strains and to determine factors enhancing their growth and, consequently, their effects on the germination of canola seeds. Under salinity stress, in 14% of the isolates, ACC deaminase activity was observed, indicating that they were able to utilize ACC as the sole N-source. Bacterial strains differed in their ability to synthesize auxin and hydrogen cyanide compounds, as well as in their ACC deaminase activity. Under salinity stress, the rate of germinating seeds inoculated with the strains of ACC deaminase-producing Pseudomonas fluorescens and Pseudomonas putida, and seedling growth was significantly higher. These results indicate the significance of soil biological activities, including the activities of plant growth-promoting bacteria, in the alleviation of soil stresses such as salinity on plant growth.     

mtDNA and Y-chromosome variation in the Talysh of Iran and Azerbaijan

The Northern Talysh from Azerbaijan and the Southern Talysh from Iran self‐identify as one ethnic group and speak a Northwestern Iranian language. However, the Northern and Southern Talysh dialects are so different that they may actually be separate languages. Does this linguistic differentiation reflect internal change due to isolation, or could contact‐induced change have played a role? We analyzed mtDNA HVI sequences, 11 Y‐chromosome bi‐allelic markers, and 9 Y‐STR loci in Northern and Southern Talysh and compared them with their neighboring groups. The mtDNA data show a close relatedness of both groups with each other and with neighboring groups, whereas the Northern Talysh Y‐chromosome variation differs from that of neighboring groups, probably as a result of genetic drift. This genetic drift most likely reflects a founder event in the male gene pool of Northern Talysh: either fewer males than females migrated to Azerbaijan, or there was a higher degree of relatedness among the male migrants. Since we find no evidence of substantial genetic contact between either Northern or Southern Talysh and neighboring groups, we conclude that internal change, rather than contact‐induced change, most likely explains the linguistic differentiation between Northern and Southern Talysh. Am J Phys Anthropol, 2009. © 2008 Wiley‐Liss, Inc.     

Novel svVEGF isoforms from Macrovipera lebetina venom interact with neuropilins

Increased vascular permeability and vasodilation are responses usually elicited by snake envenomation. In this report, we isolated from Macroviperalebetina venom two protein groups designated IC1 (Increasing Capillary1) and IC2 based on their activities on capillary permeability. Mass spectrometry analysis showed that IC1 contained four major proteins of 23,650, 24,306, 24,589 and 24,718 Da, whereas IC2 contained three major proteins of 25,101, 25,194 and 25,298 Da. N-terminal amino-acid sequencing revealed that IC1 and IC2 belong to the snake venom VEGF (svVEGF) family. IC1 and IC2 had a marked specificity for VEGFR-2, with affinities in the nanomolar range. Interestingly, they also bind to NRP1 and NRP2, with affinities in the micromolar range. This is the first report demonstrating that M. lebetina encodes several distinct svVEGFs, endowed with a capacity to interact with neuropilins. IC1 and IC2 could be valuable tools to understand the molecular properties of angiogenic factors and their receptors.     

Global phylogeographic limits of Hawaii's avian malaria

The introduction of avian malaria (Plasmodium relictum) to Hawaii has provided a model system for studying the influence of exotic disease on naive host populations. Little is known, however, about the origin or the genetic variation of Hawaii's malaria and traditional classification methods have confounded attempts to place the parasite within a global ecological and evolutionary context. Using fragments of the parasite mitochondrial gene cytochrome b and the nuclear gene dihydrofolate reductase-thymidylate synthase obtained from a global survey of greater than 13000 avian samples, we show that Hawaii's avian malaria, which can cause high mortality and is a major limiting factor for many species of native passerines, represents just one of the numerous lineages composing the morphological parasite species. The single parasite lineage detected in Hawaii exhibits a broad host distribution worldwide and is dominant on several other remote oceanic islands, including Bermuda and Moorea, French Polynesia. The rarity of this lineage in the continental New World and the restriction of closely related lineages to the Old World suggest limitations to the transmission of reproductively isolated parasite groups within the morphological species.     

Salicylic acid affects growth,essential oil and chemical compositions of thyme (Thymus daenensis Celak.) under reduced irrigation

Salicylic acid (SA) may reduce the negative impact of water deficit on growth and metabolite yield of Thymus daenensis Celak subsp. daenensis Celak. The effect of foliar application of SA and reduced irrigation on growth, oil yield, chemical components, and antibacterial and antioxidant activities of T. daenensis in field condition were investigated. Treatments comprised 0.0, 1.5 and 3.0 M SA applied to plants under normal irrigation and stressed conditions. Results indicated that irrigation regime had a significant effect on growing degree days (GDD) required to reach early and full flowering. Foliar application of SA influenced GDD from early growing stage to 50 % and full flowering, minimum radius and canopy diameter. The highest values of oil content (3.2 % v/w) and yield (14.9 g m^?2) were obtained from application of 3.0 M SA. Percentage of some chemical constituents in the essential oil extracted from the plants under stress was higher than non-stressed plants. Thymol content was significantly reduced under stressed conditions. Foliar application of SA significantly improved carvacrol, α-thujene, α-pinene and p-cymene contents in the oils, but reduced thymol and, β-caryophyllene amounts. Our results showed that foliar application of SA reduced the negative effect of water deficit on thymol content in the essential oil of T. daenensis. The essential oils of T. daenensis exhibited antioxidant and antibacterial activities when plants were sprayed with 1.5 and 3.0 M SA, respectively.     

Cellular impact of combinations of endosulfan,atrazine, and chlorpyrifos on human primary hepatocytes and HepaRG cells after short and chronic exposures

Chronic exposure to low doses of pesticides present in the environment is increasingly suspected to cause major health issues to humans. Toxicological evaluations become more complex when the exposure concerns chemical combinations. Atrazine, chlorpyrifos, and endosulfan are pesticides used worldwide in agriculture and are therefore currently found at residual levels in food and the environment, even in countries in which they are now banned. Our study aimed to use Real-Time Cell Impedance Analyzer to investigate changes in phenotypical status of primary human hepatocytes and differentiated HepaRG cells induced by short and chronic exposures to these three chemicals. In contrast to the traditionally used endpoint cytotoxicity test, this technology allows kinetic measurements in real-time throughout the entire experiment. Our data show significantly higher cytotoxic effects of mixtures as compared to individual pesticides and a greater susceptibility of human hepatocytes as compared to HepaRG to short-term exposure (24 h). Repeated exposure over 2 weeks to endosulfan and endosulfan-containing mixture induced HepaRG cell death in a time- and dose-dependent manner. Of the typical genes involved in metabolism and cell-response to xenobiotics, we found an exposure time- and condition-dependent deregulation of the expression of CYP3A4 and UGT1A in HepaRG cells exposed to low doses of pesticides and mixtures. Our data demonstrate the usefulness of real-time cell monitoring in long-term toxicological evaluations of co-exposure to xenobiotics. In addition, they support but at the same time highlight certain limitations in the use of HepaRG cells as the gold standard liver cell model in toxicity studies.     

Morphological characterization of mycorrhizae formed between three Terfezia species (desert truffles) and several Cistaceae and Aleppo pine

Six Cistaceae species, Helianthemum ledifolium, Helianthemum lippii, Fumana procumbens, Cistus albidus, Cistus incanus, Cistus salvifolius, and Pinus halepensis (Aleppo pine) were inoculated with three mycorrhizal desert truffles, Terfezia leptoderma, Terfezia boudieri, and Terfezia claveryi under greenhouse conditions, on soil originating from desert truffle natural habitat in Algeria. The syntheses have led to the formation of typical endomycorrhizae in annual Cistaceae (H. ledifolium) and perennial ones (H. lippii and F. procumbens) and an ectomycorrhiza with a less developed sheath in Cistus species and Aleppo pine. These results demonstrate the plasticity of Terfezia species to form different mycorrhizal types. The formation of an endomycorrhiza with H. ledifolium and F. procumbens and a sheathing ectomycorrhiza with P. halepensis inoculated by T. leptoderma in in vivo culture conditions was obtained for the first time.