Complete Sequences of Organelle Genomes from the Medicinal Plant Rhazya Stricta (Apocynaceae) and Contrasting Patterns of Mitochondrial Genome Evolution Across Asterids

Rhazya stricta is native to arid regions in South Asia and the Middle East and is used extensively in folk medicine to treat a wide range of diseases. In addition to generating genomic resources for this medicinally important plant, analyses of the complete plastid and mitochondrial genomes and a nuclear transcriptome from Rhazya provide insights into inter-compartmental transfers between genomes and the patterns of evolution among eight asterid mitochondrial genomes. Results: The 154,841 bp plastid genome is highly conserved with gene content and order identical to the ancestral organization of angiosperms. The 548,608 bp mitochondrial genome exhibits a number of phenomena including the presence of recombinogenic repeats that generate a multipartite organization, transferred DNA from the plastid and nuclear genomes, and bidirectional DNA transfers between the mitochondrion and the nucleus. The mitochondrial genes sdh3 and rps14 have been transferred to the nucleus and have acquired targeting presequences. In the case of rps14, two copies are present in the nucleus; only one has a mitochondrial targeting presequence and may be functional. Phylogenetic analyses of both nuclear and mitochondrial copies of rps14 across angiosperms suggests Rhazya has experienced a single transfer of this gene to the nucleus, followed by a duplication event. Furthermore, the phylogenetic distribution of gene losses and the high level of sequence divergence in targeting presequences suggest multiple, independent transfers of both sdh3 and rps14 across asterids. Comparative analyses of mitochondrial genomes of eight sequenced asterids indicates a complicated evolutionary history in this large angiosperm clade with considerable diversity in genome organization and size, repeat, gene and intron content, and amount of foreign DNA from the plastid and nuclear genomes. Conclusions: Organelle genomes of Rhazya stricta provide valuable information for improving the understanding of mitochondrial genome evolution among angiosperms. The genomic data have enabled a rigorous examination of the gene transfer events. Rhazya is unique among the eight sequenced asterids in the types of events that have shaped the evolution of its mitochondrial genome. Furthermore, the organelle genomes of R. stricta provide valuable genomic resources for utilizing this important medicinal plant in biotechnology applications.King Abdulaziz UniversityIntegrative Biolog

Transcriptomic and metabolic responses of Calotropis procera to salt and drought stress

Background: Calotropis procera is a wild plant species in the family Apocynaceae that is able to grow in harsh, arid and heat stressed conditions. Understanding how this highly adapted plant persists in harsh environments should inform future efforts to improve the hardiness of crop and forage plant species. To study the plant response to droμght and osmotic stress, we treated plants with polyethylene glycol and NaCl and carried out transcriptomic and metabolomics measurements across a time-course of five days. Results: We identified a highly dynamic transcriptional response across the time-course including dramatic changes in inositol signaling, stress response genes and cytokinins. The resulting metabolome changes also involved sharp increases of myo-inositol, a key signaling molecule and elevated amino acid metabolites at later times. Conclusions: The data generated here provide a first glimpse at the expressed genome of C. procera, a plant that is exceptionally well adapted to arid environments. We demonstrate, through transcriptome and metabolome analysis that myo-inositol signaling is strongly induced in response to drought and salt stress and that there is elevation of amino acid concentrations after prolonged osmotic stress. This work should lay the foundations of future studies in adaptation to arid environments

Anti-bacterial activity of Ricinus communis L. against bacterial pathogens Escherichia coli and Klebsiella oxytoca as evaluated by Transmission electron microscopy

The emergence of multidrug-resistant (MDR) microbes has become one of the major threat globally. Infectious diseases are the second leading cause of death, two-third of which are caused by Gram-negative bacteria. The increasing number of multidrug resistant (MDR) microbes is quite alarming and has raised the necessity of development of new antibacterial drugs. Escherichia coli and Klebsiella have been reported among the top most resistance-developing pathogens. Ricinus communis is an important medicinal plant reported to possess antimicrobial phytochemicals such as α-pinene. The hexane treated crude ethanolic extract of R. communis was evaluated against Gram-negative bacteria E. coli and Klebsiella oxytoca. The agar well diffusion assay was used to determine the antibacterial activity. In the present study, we have shown experimentally that leaf extract of R. communis can induce the deterioration of the inner and outer cell membranes of E. coli and K. oxytoca and decrease their viability at a concentration of 50 mg/ml. Transmission electron microscopic results revealed cell membrane damage, cellular disintegration and release of cytoplasmic content, leading to cell death. To our knowledge, this is the first study of the antibacterial activity of R. communis against E. coli and K. oxytoca by Transmission electron microscopy. The ultramicroscopic observations showed that the phytochemical present in the leaf extract of R. communis could penetrate the bacterial cell, causing rupture of cell membranes and hence confirm the cytotoxic and antimicrobial property of R. communis

Therapeutic role of Ricinus communis L. and its bioactive compounds in disease prevention and treatment

Ricinus communis L. (R. communis), commonly known as castor oil plant, is used as a traditional natural remedy or folkloric herb for the control and treatment of a wide range of diseases around the globe. Various studies have revealed the presence of diverse phytochemicals such as alkaloids, flavonoids, terpenes, saponins, phenolic compounds such as kaempferol, gallic acid, ricin, rutin, lupeol, ricinoleic acid, pinene, thujone and gentisic acid. These phytochemicals have been responsible for pharmacological and therapeutic effects, including anticancer, antimicrobial, insecticidal, antioxidant, anti-diabetic, antinociceptive, anti-inflammatory, bone regenerative, analgesic, and anticonvulsant activity. R. communis harbours phytochemicals which have been shown to target peroxisome proliferator activated receptor (PPAR), nuclear factor NF- κ -B, cytochrome p450, P38 mitogen-activated protein kinases kinase (p38 MAPK), tumor protein P53, B-cell lymphoma-extra-large (Bcl-xL) and vascular endothelial growth factor receptor-2 (VEGFR-2). Considering its wide variety of phytochemicals, its pharmacological activity and the subsequent clinical trials, R. communis could be a good candidate for discovering novel complementary drugs. Further experimental and advanced clinical studies are required to explore the pharmaceutical, beneficial therapeutic and safety prospects of R. communis with its phytochemicals as a herbal and complementary medicine for combating various diseases and disorders

L'Auto-vélo : automobilisme, cyclisme, athlétisme, yachting, aérostation, escrime, hippisme / dir. Henri Desgranges

17 juillet 19171917/07/17 (A18,N6021)

New Insights into Plagiogrammaceae (Bacillariophyta) Based on Multigene Phylogenies and Morphological Characteristics with the Description of a New Genus and Three New Species

<div><p>Plagiogrammaceae, a poorly described family of diatoms, are common inhabitants of the shallow marine littoral zone, occurring either in the sediments or as epiphytes. Previous molecular phylogenies of the Plagiogrammaceae were inferred but included only up to six genera: <i>Plagiogramma</i>, <i>Dimeregramma</i>, <i>Neofragilaria</i>, <i>Talaroneis</i>, <i>Psammogramma</i> and <i>Psammoneis</i>. In this paper, we describe a new plagiogrammoid genus, <i>Orizaformis</i>, obtained from Bohai Sea (China) and present molecular phylogenies of the family based on three and four genes (nuclear-encoded large and small subunit ribosomal RNAs and chloroplast-encoded <i>rbc</i>L and <i>psb</i>C). Also included in the new phylogenies is <i>Glyphodesmis</i>. The phylogenies suggest that the Plagiogrammaceae is composed of two major clades: one consisting of <i>Talaroneis</i>, <i>Orizaformis</i> and <i>Psammoneis</i>, and the second of <i>Glyphodesmis</i>, <i>Psammogramma</i>, <i>Neofragilaria</i>, <i>Dimeregramma</i> and <i>Plagiogramma</i>. In addition, we describe three new species within established genera: <i>Psammoneis obaidii</i>, which was collected from the Red Sea, Saudi Arabia; and <i>Neofragilaria stilus</i> and <i>Talaroneis biacutifrons</i> from the Mozambique Channel, Indian Ocean, and illustrate two new combination taxa: <i>Neofragilaria anomala</i> and <i>Neofragilaria lineata</i>. Our observations suggest that the biodiversity of the family is strongly needed to be researched, and the phylogenetic analyses provide a useful framework for future studies of Plagiogrammaceae.</p></div

<i>Neofragilaria stilus</i>, LM (a-b) and SEM (f-g).

<p>Cultured material SZCZM116. (a) Zigzag colony linked by valve corners, frustule rectangular in girdle view, two plastids per cell. (b) Cleaned material in valve view, linear to lanceolate, robust striae. (c) Exterior view of natural sample, showing elaborate cribra and marginal spines. (d) Interior view of natural sample, a robust sternum, rimoportulae absent. (e) Exterior view in culture, showing corroded cribra and slit-like areolae in the apical pore field. (f) Interior view, rimoportulae absent. (g) Chain colony in girdle view and plain girdle bands.</p

<i>Talaroneis biacutifrons</i>, LM (a) and SEM (b-e).

<p>Cleaned material SZCZ16205_1 from Juan de Nova in Mozambique Channel. (a) Cleaned material of valve view in different size. (b) Entire valve in valve view, showing subapical furrows on the apices and an acute spine located at each apex. (c) Entire valve view, valvocopula (see arrows) bearing a single row of puncta. (d) Detail of close ups of one apex of the specimen illustrated in Fig 10b. (e) Detail of the other apex of the specimen illustrated in Fig 10b</p