Successive changes in the ultrastructure ofOryza sativa L. cells during growth and aging

Summary The ultrastructure ofOryza sativa L. cells in suspension was determined as cells developed, matured and senesced at 3, 10, and 17 days, respectively, after transfer to fresh medium. Although cultures of 3-day-old cells contained some senescent cells, the symptoms of cell aging were very conspicuous at 10 days and were most pronounced at 17 days. The amount of cytoplasm decreased as the number of lytic areas, myelin figures and vesicle bodies increased. Other noticeable subcellular changes observed were ultrastructural modifications of mitochondria, proplastids, amyloplasts, and nuclei. Such changes were associated with a general deterioration of the lipoprotein complex of the cell during its growth. A fibrous structure without an external membrane was observed and its reported for the first time for cells grown in suspension culture.Mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture and does not imply its approval to the exclusion of other products that may also be suitable.     

Allergy to ragweed: clinical relevance in Turin

This study evaluates the contribution of ragweed tothe development of allergic manifestations in a groupof outpatients and the atmospheric pollenconcentration trend in the city of Turin (Italy) fromJanuary 1996 to December 1997.We examined 5680 subjects affected byrhinoconjunctivitis and/or bronchial asthma duringspring and summer or by perennial respiratory symptomswith seasonal increase. All subjects were submittedto: (a) a clinical questionnaire; (b) skin prick testswith standard inhalant allergens battery includingpollens of Gramineae, Compositae (Artemisia andAmbrosia), Parietaria, Plantago,Olea, Betula, house dust mite, cat and dogdanders, mould spore (Alternaria and Cladosporium); (c) measurement of specific IgEantibodies in serum (RAST). A weekly programmed Hirstspore-trap was used to sample airborne pollengrains. Pollen was identified and quantified at thePlant Biology Institute of Turin University.The highest concentration of ragweed pollen was 28.6 P/m³ in 1996 and 9.66 P/m³ in 1997.The number of subjects allergic to Ambrosiapollen alone was 8 (0.14% of the total), while thenumber of those allergic to Artemisia absinthiumwas 22 (0.38% of the total). The subjects allergicto both pollens of the Compositae family was 57(1%).Our results show a low prevalence of sensitization toragweed pollen, which is contrary to what we see inother Italian regions like Lombardy and Veneto. Onecause of low sensitization may be the low percentageof Ambrosia pollen in the atmosphere.