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Iron was resupplied to tobacco that was severely iron-deficient and the chloroplasts investigated for chlorophyll, iron content, photochemical, and development aberrations and photosystem components. Ferredoxin was purified from normal and iron deficient tobacco leaves. Lower ferredoxin and chlorophyll content in iron-deficient leaves were found compared to normal leaves. The ferredoxin from normal and iron-deficient leaves had the same molecular weight as spinach ferredoxin (Sigma Chemical Co.) and shared a similar antigenic property.Photosystem I (PSI) acti vity increased by about 100% during the first 10 days of regreening on a leaf surface area comparison. Only small increases in activity were found with PSII. Purified PSI particles were spectrophotometrically examined for any changes in P700, chlorophyll, cytochrome and protein components on a leaf area basis. With greening the individual components increased but the ratios remained constant. There were 6 polypeptide bands in the PSI particles when examined by electrophoresis. All bands stained with equal intensity with coomassie blue except for the ISkD band at day 0 of greening. Data suggest that iron stress is involved in the regulation of PSI development, possibly by the direct regulation of a low-molecular weight protein required for system assembly. Discussion is presented suggesting this protein is ferredoxin and that limitation of this component would directly affect chlorophyll biosynthesis and chloroplast structure.

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We determined the complete nucleotide sequences of the cognate L1 double-stranded RNA segments of bluetongue virus (BTV) serotypes 2, 11, 13, and 17, which encode the putative RNA-directed RNA polymerase VP1. Each L1 gene contained 3944 nucleotides and was 10 bases shorter than the previously reported L1 gene of BTV 10. A single open reading frame which could encode the reported VP1 protein, 1302 amino acids in size, began with an initiation codon at nucleotides 12-14 and a termination codon at nucleotides 3918-3920. Analyses of the nucleotides of L1 genes and the deduced amino acid sequences of VP1 proteins of the five U.S. BTV serotypes indicated that the most recently isolated BTV-2 serotype from Florida was more distantly related than BTV-10, 11, 13, and 17, which were isolated primarily in the western U.S.A. The results are consistent with our hypothesis that BTVs-10, -11, -13, and -17 are derived from a single and common gene pool, and that BTV-2 belongs to a second, distinct gene pool. These genetic distinctions also reflected well with the known geographic distribution of the five U.S. BTV serotypes in North America. This putative RNA-directed RNA polymerase (149 KDa) was a basic protein, and the deduced amino acid sequences of the VP1 proteins contained seven highly conserved hydrophobic domains and many other sequence motifs which were also found in other known RNA polymerases. Four immunodominant but linear antigenic epitopes conserved among the VP1 of five U.S. BTVs were also been identified and mapped using monospecific oligoclonal antibodies.

Medicinal plants have long been used as a source of therapeutic agents. They are thought to be important anti-aging ingredients in prophylactic medicines. The aim of this study was to screen extracts from Taiwanese plant materials for phenolic contents and measure the corresponding matrix metalloproteinase-9 (MMP-9) activity. We extracted biological ingredients from eight plants native to Taiwan (Alnus formosana, Diospyros discolor, Eriobotrya deflex, Machilus japonica, Pyrrosia polydactylis, Pyrus taiwanensis, Vitis adstricta, Vitis thunbergii). Total phenolic content was measured using the Folin-Ciocalteu method. MMP-9 activities were measured by gelatin zymography. The extracted yields of plants ranged from 3.7 % to 16.9 %. The total phenolic contents ranged from 25.4 to 36.8 mg GAE/g dry material. All of these extracts (except Vitis adstricta Hance) were shown to inhibit MMP-9 activity of WS-1 cell after ultraviolet B irradiation. These findings suggest that total phenolic content may influence MMP-9 activity and that some of the plants with higher phenolic content exhibited various biological activities that could serve as potent inhibitors of the ageing process in the skin. This property might be useful in the production of cosmetics.