Changes in water status during water stress at different stages of development in wheat

The dynamics of stomatal resistance and osmotic adjustment in response to plant water deficits and stage of physiological development was studied in the leaves of spring wheat ( Triticum aestivum L., GWO 1809). Plants were germinated and grown in pots in a growth chamber at the Duke University Phytotron to four physiological stages of development (4th leaf, 7th leaf, anthesis, and soft dough), during which time stomatal resistance, total water potential and osmotic potential were measured on the last fully developed leaf of water stressed and non-stressed plants. Pressure potential was obtained by difference. Stomatal closure of the abaxial and adaxial surfaces were independent of each other, each having a different critical total water potential. The total water potential required to close the stomata on the last fully developed leaf were different at different stages of physiological development, decreasing as the plants grew older. The development of osmoregulation in wheat allows the closure of stomata during the vegetative stage at a high total water potential, but insures that stomata remain open from anthesis through the ear filling period to a lower total water potential.     

Synthesis of some novel 6-benzyl(or substituted benzyl)-2-beta-D-glucopyranosyl-1,2,4-triazolo[4,3-b][1,2,4]triazines as potential antimicrobial chemotherapeutics

Glucosidation of the new 8-amino-6-benzyl(or substituted benzyl)-2,8-dihydro-1,2,4-triazolo[4,3-b][1,2,4]triazin-7(3H)-ones (3a-d) with 2,3,4,6-tetra-O-acetyl-alpha-D-glucopyranosyl bromide 4 gave the corresponding N-glucosides 5a-d. Chemical transformations leading to new functionalities have also been achieved to give compounds 7-12. Antimicrobial activity of compounds 5a-c against Aspergillus fumigatus, Penicillium italicum, Syncephalastrum racemosum, Candida albicans, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, Escherichia coli is described.     

Safety and efficacy of granulocyte–colony-stimulating factor administration following autologous intramuscular implantation of bone marrow mononuclear cells: a randomized controlled trial in patients with advanced lower limb ischemia

Background aimsThe aim was to investigate the therapeutic effect of granulocyte–colony-stimulating factor (G-CSF) administration following implantation of autologous bone marrow mononuclear cells (BM MNC) for patients with lower limb ischemia.MethodsThe design was a randomized controlled trial. Fifteen patients with severe chronic limb ischemia were treated with autologous BM MNC [without G-CSF (MNC–G-CSF) or combined with G-CSF administration for 5 days following transplantation (MNC+G-CSF)].ResultsAll clinical parameters, including ankle brachial index, visual analog scale and pain-free walking distance, showed a mean improvement from baseline, which was measured at 4 and 24 weeks after transplantation in both groups. However, in three (20%) patients, the clinical course did not improve and limb salvage was not achieved. No significant difference was observed among the patients treated in the MNC–G-CSF and MNC+G-CSF groups. No severe adverse reactions were reported during the study period. No relationship was observed between both the numbers of viable MNC or CD34⁺ cells and the clinical outcome.ConclusionsAutologous transplantation of BM MNC into ischemic lower limbs is safe, feasible and efficient for patients with severe peripheral artery disease. However, the administration of G-CSF following cell transplantation does not improve the effect of BM MNC implantation and therefore would not have any beneficial value in clinical applications of such cases.     

Synthesis of Novel α-l-Arabinopyranosides of β-Lactams with Potential Antimicrobial Activity

Synthetic routes toward the synthesis of some novel 1-(2,3,4-tri-O-acetyl-α-l-arabinopyranosyl)-azetidin-2-ones are described. Antimicrobial screening of three selected compounds revealed their activity against Bacillus subtilis and Escherichia coli.     

A maize defense-inducible gene is a major facilitator superfamily member related to bacterial multidrug resistance efflux antiporters

A defense-inducible maize gene was discovered through global mRNA profiling analysis. Its mRNA expression is induced by pathogens and defense-related conditions in various tissues involving both resistant and susceptible interactions. These include Cochliobolus heterostrophus and Cochliobolus carbonum infection, ultraviolet light treatment, the Les9 disease lesion mimic background, and plant tissues engineered to express flavonoids or the avirulence gene avrRxv. The gene was named Zm-mfs1 after it was found to encode a protein related to the major facilitator superfamily (MFS) of intregral membrane permeases. It is most closely related to the bacterial multidrug efflux protein family, typified by the Escherichia coli TetA, which are proton motive force antiporters that export antimicrobial drugs and other compounds, but which can be also involved in potassium export/proton import or potassium re-uptake. Other related plant gene sequences in maize, rice, and Arabidopsis were identified, three of which are introduced here. Among this new plant MFS subfamily, the characteristic MFS motif in cytoplasmic TM2-TM3 loop, and the antiporter family motif in transmembrane domain TM5 are both conserved, however the TM7 and the cytoplasmic TM8-TM9 loop are divergent from those of the bacterial multidrug transporters. We hypothesize that Zm-Mfs1 is a prototype of a new class of plant defense-related proteins that could be involved in either of three nonexclusive roles: (1) export of antimicrobial compounds produced by plant pathogens; (2) export of plant-generated antimicrobial compounds; and (3) potassium export and/or re-uptake, as can occur in plant defense reactions.     

Redox-controlled,in vivo and in vitro phosphorylation of the α subunit of the light-harvesting complex I in Rhodobacter capsulatus

Labelling of Rhodobacter capsulatus cells with (³²P)Pi in a phototrophic culture results in phosphorylation of a membrane-bound polypeptide identified as the subunit of the LHI antenna complex of the photosynthetic apparatus. Phosphorylation of the same polypeptide was also observed by incubation of chromatophores with (³²P)ATP or under conditions of photophosphorylation with ADP and (³²P)Pi. The identity of the phosphorylated LHI- subunit was demonstrated by N-terminal protein sequencing of the phosphorylated polypeptide and by failure of labelling in LHI-defective mutants. Pre-aeration of the samples or addition of the oxidant potassium ferrcyanide stimulated the kinase activity whereas the presence of soluble cytoplasmic proteins impaired phosphorylation in an in vitro assay. No effect resulted from addition of reductants to the assay medium. The results indicate the presence of a membrane-bound protein kinase in R. capsulatus that phosphorylates the subunit of the LHI antenna complex under redox control.Abbreviations Pi inorganic phosphate - SDS-PAGE sodium dodecyl-sulfate polyacrylamide gel electrophoresis