Mulberry moracins: scavengers of UV stress-generated free radicals

Mulberry leaves treated with UV-C were found to accumulate three different phytoalexins, moracin C, moracin N, and chalcomoracin. The increased level of malondialdehyde in UV-treated leaves along with moracins suggested their role as a free-radical scavenger in stressed plants. All the three moracins induced under UV stress were capable of scavenging the superoxide anion generated by the xanthine-xanthine oxidase system. Also, moracins were capable of inhibiting lipid peroxidation, which strongly indicates their role as a scavenger.     

rtpA, a gene encoding a bacterial two-component sensor kinase, determines pathogenic traits ofPseudomonas tolaasii, the causal agent of brown blotch disease of a cultivated mushroom,Pleurotus ostreatus

Pseudomonas tolaasii strain PT814 produces extracellular toxins, tolaasins, and a volatile toxin, tovsin, that are responsible for the induction of brown blotch and rotting, respectively, in a cultivated mushroom,Pleurotus ostreatus. Insertions of single transposon mini-Tn5Km 1 into the chromosome ofP. tolaasii strain PT814 generated mutants that are pleiotropically defective in tolaasin and protease production, and altered in colony morphology. The mutants, however, produce tovsin at the level of wild-type. Variants phenotypically similar to the pleiotropic mutants ofP. tolaasii strain PT814 spontaneously occurred inP. tolaasii strain S8501 at 22–30°C in vitro. The occurrence of variants was significantly reduced in the presence of extracts ofP ostreatus or at a temperature of 15–20°C. ThertpA gene (rtpA=regulator gene of tolaasin production and other pleiotropic traits) isolated from aP. tolaasii strain PT814 gene library restored the wild-type phenotype in both the mini-Tn5km 1 insertion and spontaneous mutants. mini-Tn5km 1 insertions were also located in the allele ofrtpA. Nucleotide sequencing of thertpA DNA revealed an open reading frame of 2,751 bp predicted to encode a protein consisting of 917 amino acid residues with a molecular mass of 100.6 kDa and displaying the conserved amino acid sequence of both sensor, and receiver domains of “bacterial two-component regulators”. The data suggest that the machinery responding to environmental stimuli is essential for the pathogenic interaction ofP. tolaasii with the mushroom.     

Significance of AgNOR measurement in thyroid lesions

OBJECTIVE: To evaluate the discriminating potential of AgNOR area measurement and count in thyroid tumors using static cytometry equipment. STUDY DESIGN: Slides were analyzed by a computerized system for image analysis, CAS 200 (Becton & Dickinson, U.S.A.), using the Cell Measurement computer program (CAS 200, Becton & Dickinson). The argyrophilic reaction (NORs) was evaluated with a 400-fold amplification directly from the computer monitor. RESULTS: Thirty-three cases were analyzed for AgNOR staining. The cases studied included 3 goiters, 10 follicular adenomas, 6 Hürthle adenomas, 4 follicular carcinomas, 7 papillary carcinomas, and 3 Hürthle carcinomas. A total of 6,600 nuclei were evaluated. For statistical purposes, lesions were classified as benign and malignant, and both the number and the area of counted NORs showed very similar values. The NORs median among 19 benign tumors was 1.484 (SD +/- 0.265) and of 14 malignant tumors was 1.436 (SD +/- 0.414); the NORs areas were 2.6584 (SD +/- 1.0653) and 2.3643 (SD +/- 0.6320), respectively. CONCLUSION: Our results showed that AgNOR evaluation was not a significant parameter to discriminate between malignant and benign thyroid lesions.     

Effect of Alteration of Sterol Composition on the Salt Sensitivity of a Tobacco Cell Suspension Culture

A Nicotiana tabacum cell line, KS-1, which is tolerant to morethan 1% NaCl, was treated with buthiobate. The cells accumulated14a-methylsterols such as obtusifoliol, instead of campesteroland sitosterol. The buthiobate-treated cells lost their salttolerance. These results suggest that the buthiobate-inducedsalt sensitivity is closely associated with changes in the molecularspecies of sterols in the cell membranes. (Received October 16, 1986; Accepted April 13, 1987)     

Accumulation of Rare Phytosterols in Plant Cells on Treatment with Metabolic Inhibitors and Mevalonic Acid

Root application of the metabolic inhibitors D-ethionine (100µM) and L-ethionine (30 µM), which were expectedto inhibit alkylation of the sterol side chains, merely reducedthe sterol content in the roots of Medicago sativa seedlings.The major sterol was stigmasterol. However, when (3RS)-mevalonicacid (2 mM) was applied together with ethionine, cydoartenol(about 50% of the total sterols) accumulated in the roots. Thehypocotyls of the ethionine-treated seedlings accumulated cholesterol(34% of the total sterols), and mevalonic acid showed no additionaleffect in this case. In a suspension culture of Nicotiana tabacum, the most abundantsterol was campesterol. When cells were treated with buthiobate(100 µM), a potent inhibitor of lanosterol 14-demethylationin yeasts and fungi, obtusifoliol accumulated in the treatedcells (50% of the total sterols). 14-Methylfecosterol also accumulatedin the treated cells. The addition of mevalonic acid (1 mM togetherwith buthiobate increased the obtusifoliol content (63% of thetotal sterols). (Received October 16, 1986; Accepted April 2, 1987)     

Performance of 3 methods for quality control for gynecologic cytology diagnoses

OBJECTIVE: To evaluate performance and viability of internal quality control (QC) strategies in a public health laboratory of the state of S?o Paulo. STUDY DESIGN: A retrospective study was performed with 3 QC strategies to improve internal cytologic diagnoses: morphologic guided-list criteria (MGLC), 100% rapid-rescreening (100% RR) of negative slides ("turret" method) and 10% rescreening (10% R) of negative slides. Cases were examined at Adolfo Lutz Institute, S?o Paulo, Brazil, from 2002 to 2004. Histopathologic results, when available, were considered gold standard; cytologic consensus diagnosis was by 2 pathologists when histologic results were unavailable. RESULTS: MGLC selected 20.7% samples with cytologic atypias, 10% R selected 0.6% and RR selected 2.5%. Cytologic/histologic initial concordance was 57.4%, low-grade squamous intra-epithelial lesion false negative rate was 34.9% and high-grade squamous intraepithelial lesion false negative rate was 12.2%. After diagnosis, consensus concordance was 97.2%. CONCLUSION: The 100% RR and 10% R QC strategies detected more false negative cases in liquid-based cytology than in conventional Pap smears. The 100% RR strategy reduced the false negative results and allowed evaluation of individual staff performance. The 10% R strategy did not offer significant results. We concluded that association of MGLC and 100% RR strategies might improve cytologic diagnostic quality.     

Observation of water and Na+ in tissues of theBruguiera gymnorrhiza by1H-and23Na-NMR imaging

Distributions of free water, which is called water in this investigation, in mangrove (Bruguiera gymnorrhiza (L.) Lam.) tissues were examined by using¹H-NMR imaging, and accumulation of Na⁺ in hypocotyls was examined by using high resolution²³Na-NMR and²³Na-NMR imaging in relation to their morphology. Water located preferentially in the epidermis and the outer layer of cortex adjacent to the epidermis, and around vascular bundles of a root, a branch stem, and hypocotyls. Amount of water detected in the middle parts of cortex and pith was small unlikeAucuba japonica branch tissue. On the other hand, relatively high concentration of Na⁺ was detected in the pith besides the epidermis and the outer layer of the cortex adjacent to the epidermis, and around vascular bundles of the hypocotyl. The localization of Na⁺ did not correspond to that of water. Concentrations of Na⁺ accumulated (up to 22mM) in the hypocotyl were approximately 10 times higher than those observed in tissues of ordinary plants. The characteristic water distribution and accumulation of Na⁺ in the mangrove are considered to relate to their ecological nature for the adaptation to saline environments.