The Differential Susceptibility of Vetch (Vicia spp.) to Orobanche aegyptiaca: Anatomical Studies

Vetches (Vicia spp .) are important forage legumes in the MiddleEast and Mediterranean regions. Most vetches are highly susceptibleto the root holoparasites Orobanche aegyptiaca and O. crenata,suffering severe quality and yield losses. However, purple vetch(V. atropurpurea) has shown good resistance to Orobanche. Microscopicstudies were performed to reveal anatomical differences of host-parasiteinteractions between susceptible and resistant vetch. SusceptibleV. sativa‘Yovel’ and resistant V. atropupurea‘Popany’were grown in association with O. aegyptiaca seeds, on glassmicrofibre sheets in a polyethylene-bag system. Whole root observationsusing stereoscopic microscopy detected necrotic lesions surroundingthe attachments of Orobanche radicles on resistant vetch roots.Hand-cut sections examined under the light microscope revealedthat in both susceptible and resistant vetch genotypes the Orobancheseeds germinated, attached and penetrated the host root epidermisand cortex. A reddish-brown secretion was observed in the apoplastat the interface between the parasite haustorium and the hosttissues, including the cell walls of the resistant vetch xylemvessels. Fixed and embedded sections observed under the lightmicroscope showed that in the susceptible genotype the parasitehaustorium penetrated through the endodermis into the host vascularcylinder, successfully forming a continuum with host vascularvessels. However, in the resistant genotype, the parasite haustoriumwas blocked at the root endodermis layer. The blockage was coupledwith secretion of unidentified material, thus preventing theparasite from establishing. These findings indicate that mechanicaland possibly chemical barriers are responsible for the hostdefence mechanism(s) conferring resistance of V. atropurpureato O. aegyptiaca. Copyright 2000 Annals of Botany Company Broomrape, Vicia atropurpurea, Vicia sativa, parasitic plants, plant resistance, tissue sections.     

Surgical treatment of nasal obstruction secondary to craniofacial fibrous dysplasia

Craniofacial fibrous dysplasia, a skeletal disorder most often affecting the mandible or maxilla, can cause a variety of complications. Nasal obstruction secondary to this unusual disorder presents a diagnostic and therapeutic challenge. The nasal obstruction in this case is due to expansion of fibrous lesions in adjacent bones as well as direct involvement of the turbinates with fibrous dysplasia. We describe the surgical correction of nasal obstruction in this unique setting and present a brief update of this intriguing disorder.     

Effects of high and low molecular soluble factors of the bone marrow on antibody formation and pain sensitivity in animals

In addition to the immunostimulating activity, bone marrow mediators, myelopeptides (MP) show the dose-dependent effect on the development of pain sensitivity in mice. When injected in nanogram amounts, MP induce hyperalgesia and 3-9 fold higher production of antibodies against SREC. When injected in milligram amounts, they exhibit hypoalgesic effect and no influence on antibody production. Immunostimulating effect in MP (mol, mass less than 1 KD, fraction 3) is accompanied with hypoalgesia. Bone marrow factors of mol. masses 40-150 KD (fraction 1) eluted at Sephadex G-25 gel-filtration before MP enhance the pain sensitivity tHreshold and show a potent immunodepressive effect. Thus the bone marrow factors are capable of exhibiting the opposite effects on the immune system in the pain control system that evidences the tight interrelation between these systems.     

PARATI – a dynamic model for radiological assessments in urban areas

The structure and mathematical model of PARATI, a detailed computer programme developed for the assessment of the radiological consequences of an accidental contamination of urban areas, is described with respect to the scenarios used for the estimation of exposure fields in a village or town, the models for the initial and secondary contamination with the radionuclide ¹³⁷Cs, the concepts for calculating the resulting radiation exposures and the changes with time of the contamination and radiation fields. Kerma rates at various locations in tropical urban areas are given, and the contribution of different contaminated surfaces to these rates after dry or wet deposition are discussed. Received: 12 April 1996 / Accepted in revised form: 30 August 1996     

High levels of expression of full length human pro-alpha 2(V) collagen cDNA in pro-alpha 2(V)-deficient hamster cells

A full length cDNA encoding human pro-alpha 2(V) collagen was constructed. Partial sequencing of the cDNA and primer extension analysis of mRNA from fibroblasts found that pro-alpha 2(V) mRNA differs from the mRNAs of other fibrillar collagens in the increased length of its 5'-untranslated region. The pro-alpha 2(V) cDNA was placed downstream of the human cytomegalovirus immediate early promoter/regulatory sequences for expression studies in cultured Chinese hamster lung cells. These cells have been shown previously to synthesize large quantities of pro-alpha 1(V) homotrimers as their only collagenous product. Transfection resulted in a number of clonal cell lines that express human alpha 2(V) RNA at levels comparable to, and in some cases greater than, levels found in normal human skin fibroblasts. Pro-alpha 2(V) chains produced in the majority of clonal lines were of sufficient quantity to complex all available endogenous pro-alpha 1(V) chains. Chimeric heterotrimers, composed of hamster alpha 1(V) and human alpha 2(V) chains in a 2:1 ratio, were stable to pepsin digestion and were found predominantly associated with the cell layer. Surprisingly, pro-alpha 2(V) chains, in excess to pro-alpha 1(V) chains, were found in the extracellular matrix and, in much greater abundance, in media. These chains were pepsin sensitive, indicating that pro-alpha 2(V) chains can be secreted as nonstable homotrimers or as free chains.     

Ubiquinol prevents alpha-tocopherol consumption during liposome peroxidation

In this study we investigated whether alpha-tocopherol can be spared by ubiquinol-3 during autoxidation of multilamellar liposome. A lipophilic azocompound, 2,2'-azobis-(2,4-dimethyl-valeronitrile), was chosen to initiate liposome autoxidation. The effect of either alpha-tocopherol, ubiquinol-3, or a mixture of them was compared. Rates of conjugated diene formation and concomitant disappearance of the two antioxidants was measured. Since the inhibition rate constant for the scavenging of peroxyl radical for alpha-tocopherol was higher than that for quinol-3, it was concluded that alpha-tocopherol is regenerated by ubiquinol-3.