Photosynthetic Efficiency and Anatomical Structure of Pepper Leaf (Capsicum annuum L.) Transplants Grown under High-Pressure Sodium (HPS) and Light-Emitting Diode (LED) Supplementary Lighting Systems.

The aim of this study was to evaluate the effects of various supplemental greenhouse lighting systems, i.e., high-pressure sodium lamps and mixtures of red and blue light-emitting diodes, on the photochemical efficiency, anatomical leaf structure, and growth of the two pepper cultivars. The intensity levels of the photosynthetically active radiation were the same for both light treatments. In this study, the relative chlorophyll content was measured. Additionally, certain parameters of chlorophyll a fluorescence were measured under ambient light or after dark adaptation. The obtained results showed that the application of light-emitting diodes (LEDs) as supplemental lighting positively affected the anatomical leaf characteristics and plant growth. The leaves of both pepper cultivars were thicker and had larger palisade parenchyma cells under LED supplemental lighting compared to leaves grown under high-pressure sodium (HPS) lamps. Moreover, the mesophyll cells of seedlings grown under LEDs contained more chloroplasts than those growing under HPS lighting. The chlorophyll a fluorescence measurements of pepper seedlings grown under LEDs showed significant increases in photosynthetic apparatus performance index (PI) values compared to plants grown under HPS lamps; however, the values for this index were higher in cv. 'Aifos' as compared to cv. 'Palermo'. We recommend that supplemental lighting systems are applied with caution, as their performance appears to depend not only on the light spectrum but also on the cultivar.

Structural and functional disorder in the photosynthetic apparatus of radish plants under magnesium deficiency.

Magnesium (Mg) is one of the significant macronutrients which is involved in the structural stabilisation of plant tissues and many enzymes such as PSII. The latter efficiency and performance were analysed, using chlorophyll (Chl) a fluorescence induction kinetics and microscopic images, to detect the changes in structure and function of photosynthetic apparatus of radish plants grown under Mg deficiency (Mgdef). Plants grown under Mgdef showed less PSII connectivity and fewer active primary electron acceptors (QA) oxidizing reaction centres than control plants. Confocal and electron microscopy analyses showed an increased amount of starch in chloroplasts, and 3,3'-diaminobenzidine (DAB)-uptake method revealed higher H2O2 accumulation under Mgdef. Prominent changes in the Chl a fluorescence parameters such as dissipated energy flux per reaction centre (DIo/RC), relative variable fluorescence at 150µs (Vl), and the sum of the partial driving forces for the events involved in OJIP fluorescence rise (DFabs) were observed under Mg deficiency. The latter also significantly affected some other parameters such as dissipated energy fluxes per cross-section (DIo/CSo), performance index for energy conservation from photons absorbed by PSII antenna until the reduction of PSI acceptors (PItotal), and relative variable fluorescence at 300µs (Vk). This work emphasises the use of chlorophyll fluorescence in combination with microscopic and statistical analyses to diagnose the effects of nutrients deficiency stress on plants at an early stage of its development as demonstrated for the example of Mgdef. Due to the short growth period and simple cultivation conditions of radish plant we recommend it as a new standard (model) plant to study nutrients deficiency and changes in plant photosynthetic efficiency under stress conditions.

meta-Tyrosine induces modification of reactive nitrogen species level, protein nitration and nitrosoglutathione reductase in tomato roots.

A non-protein amino acid (NPAA) - meta-Tyrosine (m-Tyr), is a harmful compound produced by fescue roots. Young (3-4 days old) tomato (Solanum lycopersicum L.) seedlings were supplemented for 24-72 h with m-Tyr (50 or 250 µM) inhibiting root growth by 50 or 100%, without lethal effect. Fluorescence of DAF-FM and APF derivatives was determined to show reactive nitrogen species (RNS) localization and level in roots of tomato plants. m-Tyr-induced restriction of root elongation growth was related to formation of nitrated proteins described as content of 3-nitrotyrosine. Supplementation with m-Tyr enhanced superoxide radicals generation in extracts of tomato roots and stimulated protein nitration. It correlated well to increase of fluorescence of DAF-FM derivatives, and transiently stimulated fluorescence of APF derivatives corresponding respectively to NO and ONOO- formation. Alterations in RNS formation induced by m-Tyr were linked to metabolism of nitrosoglutathione (GSNO). Activity of nitrosoglutatione reductase (GSNOR), catalyzing degradation of GSNO was enhanced by long term plant supplementation with m-Tyr, similarly as protein abundance, while transcripts level were only slightly altered by tested NPAA. We conclude, that although in animal cells m-Tyr is considered as a marker of oxidative stress, its secondary mode of action in tomato plants involves perturbation in RNS formation, alteration in GSNO metabolism and modification of protein nitration level.

Toxicity of canavanine in tomato (Solanum lycopersicum L.) roots is due to alterations in RNS, ROS and auxin levels.

Canavanine (CAN) is non-proteinogenic aminoacid and a structural analog of arginine (Arg). Naturally, CAN occurs in legumes e.g. jack bean and is considered as a strong allelochemical. As a selective inhibitor of inducible nitric oxide synthase in mammalians, it could act as a modifier of nitric oxide (NO) concentration in plants. Modifications in the content of endogenous reactive nitrogen species (RNS) and reactive oxygen species (ROS) influence root structure and architecture, being also under hormonal control. The aim of the work was to investigate regulation of root growth in tomato (Solanum lycopersicum L. cv. Malinowy Ozarowski) seedling by application of CAN at concentration (10 and 50 µM) leading to 50% or 100% restriction of root elongation. CAN at higher concentration led to slight DNA fragmentation, increased total RNA and protein level. Decline in total respiration rate after CAN supplementation was not associated with enhanced membrane permeability. Malformations in root morphology (shorter and thicker roots, limited number of lateral roots) were accompanied by modification in NO and ONOO(-) localization; determined mainly in peridermal cells and some border cells. Although, CAN resulted in low RNS production, addition of exogenous NO by usage of NO donors did not reverse its negative effect, nor recovery effect was detected after roots imbibition in Arg. To build up a comprehensive view on mode of action of CAN as root growth inhibitor, it was shown an elevated level of auxin. To summarize, we demonstrated several secondary mode of action of CAN, indicating its toxicity in plants linked to restriction in RNS formation accompanied by simultaneous overaccumulation of ROS.

Pectins esterification in the apoplast of aluminum-treated pea root nodules.

Aiming to elucidate the possible involvement of pectins in aluminum-mediated growth inhibition the distribution of pectins in the apoplast of root nodules was investigated. Experiments were performed on the pea (Pisum sativum L.) root nodules treated with aluminum (50 µM AlCl3, for 2 or 24h). For histochemical acidic pectin localization we used ruthenium red staining. Immunolabeling techniques with monoclonal antibodies specific to high methyl-esterified pectin (JIM7), low methyl-esterified pectin (JIM5) and calcium cross-linked pectin (2F4) were used to re-examine the pattern of pectin esterification and distribution. After immunolabeling the samples were observed using a fluorescent and transmission electron microscope. Ruthenium red staining showed that acid pectin content increased in the apoplast of Al-treated nodules and immunolocalization of pectin epitopes revealed that the fraction of de-esterified pectins increased significantly under Al stress. JIM5 and 2F4 epitopes were located on the inner surface of the primary cell wall with higher intensity at cell corners lining the intercellular spaces and at infection threads (ITs) walls. By contrast, JIM 7 labels all walls uniformly throughout the nodule. In the presence of Al, the increase of JIM5 and 2F4 labeling in thick plant and IT walls, together with a decrease of JIM7 labeling was observed. These results indicate a specific role for pectin de-esterification in the process of wall thickening and growth inhibition. In particular, Al-dependent increase in pectin content and their low methyl esterification degree correlate with wall thickness and higher rigidity, and in this way, may affect IT and nodules growth.

Visualisation of plastid outgrowths in potato (Solanum tuberosum L.) tubers by carboxyfluorescein diacetate staining.

KEY MESSAGE: We describe two types of plastid outgrowths visualised in potato tubers after carboxyfluorescein diacetate staining. Probable esterase activity of the outgrowths has been demonstrated for the first time ever. Plastid outgrowths were observed in the phelloderm and storage parenchyma cells of red potato (S. tuberosum L. cv. Rosalinde) tubers after administration of carboxyfluorescein diacetate stain. Endogenous esterases cleaved off acetic groups to release membrane-unpermeable green fluorescing carboxyfluorescein which accumulated differentially in particular cell compartments. The intensive green fluorescence of carboxyfluorescein exhibited highly branched stromules (stroma-filled plastid tubular projections of the plastid envelope) and allowed distinguishing them within cytoplasmic strands of the phelloderm cells. Stromules (1) were directed towards the nucleus or (2) penetrated the whole cells through the cytoplasmic bands of highly vacuolated phelloderm cells. Those directed towards the nucleus were flattened and adhered to the nuclear envelope. Stromule-like interconnections between two parts of the same plastids (isthmuses) were also observed. We also documented the formation of another type of the stroma-filled plastid outgrowths, referred to here as protrusions, which differed from previously defined stromules in both morphology and esterase activity. Unlike stromules, the protrusions were found to be associated with developmental processes leading to starch accumulation in the storage parenchyma cells. These results strongly suggest that stromules and protrusions exhibit esterase activity. This has been demonstrated for the first time. Morphological and biochemical features as well as possible functions of stromules and protrusions are discussed below.

Accumulation and localization of extensin protein in apoplast of pea root nodule under aluminum stress.

Cell wall components such as hydroxyproline-rich glycoproteins (HRGPs, extensins) have been proposed to be involved in aluminum (Al) resistance mechanisms in plants. We have characterized the distribution of extensin in pea (Pisum sativum L.) root nodules apoplast under short (for 2 and 24h) Al stress. Monoclonal antibodie LM1 have been used to locate extensin protein epitope by immunofluorescence and immunogold labeling. The nodules were shown to respond to Al stress by thickening of plant and infection thread (IT) walls and disturbances in threads growth and bacteria endocytosis. Immunoblot results indicated the presence of a 17-kDa band specific for LM1. Irrespective of the time of Al stress, extensin content increased in root nodules. Further observation utilizing fluorescence and transmission electron microscope showed that LM1 epitope was localized in walls and intercellular spaces of nodule cortex tissues and in the infection threads matrix. Al stress in nodules appears to be associated with higher extensin accumulation in matrix of enlarged thick-walled ITs. In addition to ITs, thickened walls and intercellular spaces of nodule cortex were also associated with intense extensin accumulation. These data suggest that Al-induced extensin accumulation in plant cell walls and ITs matrix may have influence on the process of IT growth and tissue and cell colonization by Rhizobium bacteria.

Localization of hydrogen peroxide accumulation and diamine oxidase activity in pea root nodules under aluminum stress.

Aluminum (Al) is one of the environmental stressors that induces formation of reactive oxygen species (ROS) in plants. Hydrogen peroxide (H2O2) and H2O2-generated apoplast diamine oxidase (DAO) activity were detected cytochemically via transmission electron microscopy (TEM), in pea (Pisum sativum L.) root nodules exposed to high (50 µM AlCl3, for 2 and 24h) Al stress. The nodules were shown to respond to Al stress by disturbances in infection thread (IT) growth, bacteria endocytosis, premature degeneration of bacteroidal tissue and generation of H2O2 in nodule apoplast. Large amounts of peroxide were found at the same sites as high DAO activity under Al stress, suggesting that DAO is a major source of Al-induced peroxide accumulation in the nodules. Peroxide distribution and DAO activity in the nodules of both control plants and Al-treated ones were typically found in the plant cell walls, intercellular spaces and infection threads. However, 2 h Al treatment increased DAO activity and peroxide accumulation in the nodule apoplast and bacteria within threads. A prolonged Al treatment (24 h) increased the H2O2 content and DAO activity in the nodule apoplast, especially in the thread walls, matrix and bacteria within infection threads. In addition to ITs, prematurely degenerated bacteroids, which occurred in response to Al, were associated with intense staining for H2O2 and DAO activity. These results suggest the involvement of DAO in the production of a large amount of H2O2 in the nodule apoplast under Al stress. The role of reactive oxygen species in pea-Rhizobium symbiosis under Al stress is discussed.

A correlative study of hydrogen peroxide accumulation after mercury or copper treatment observed in root nodules of Medicago truncatula under light, confocal and electron microscopy.

Heavy metal stress affects both, nodulation and nitrogen fixation of legumes. Mercury triggers disturbances in cellular structure and metabolism but its influence on ROS generation is poorly understood. Copper is redox active metal which in opposition to mercury is an essential micronutrient for plants. Excess of copper is cytotoxic, as it participates in ROS generation via Fenton-type reaction. The present work describes changes in hydrogen peroxide (H2O2) accumulation in response to monthly stress caused by mercury (6 mg/L HgCl2) or copper (60 mg/L CuCl2) in root nodules. H2O2 accumulation viewed with a light microscopy was detected by the use of diaminobenzidine (DAB). 2',7'-Dichlorofluorescein diacetate (H2DCF-DA) was used as a probe for the intracellular localization of H2O2 with a confocal laser scanning system. H2O2 detection under transmission electron microscopy was performed by the use of cerium method. Histochemical localization and light and confocal microscopy investigations revealed that under Hg or Cu treatments distinct amount of H2O2 accumulated mainly in the interzone and nitrogen-fixing zone. Under normal conditions H2O2 accumulated predominantly in the interzone. Electron microscopy observations showed H2O2 accumulation under Hg or Cu- treatments around peribacteroid membranes of mature symbiosomes located within nitrogen-fixing zone. It should be underlined that under normal conditions H2O2 was not detected at the peribacteroid membranes. The main result of our observations is increased accumulation of H2O2 in response to mercury and copper treatments at the peribacteroidal membranes, to our knowledge shown for the first time. Therefore, our results revealed that an overproduction of H2O2 in response to copper or mercury-treatment may account for lowering of nitrogen fixation rates in heavy-metal affected root nodules.

Movement of fluorescent dyes Lucifer Yellow (LYCH) and carboxyfluorescein (CF) in Medicago truncatula Gaertn. roots and root nodules.

Lucifer Yellow (LYCH) and carboxyfluorescein (CF) served in Medicago truncatula roots and root nodules as the markers of apoplastic and symplastic transport, respectively. The aim of this study was to understand better the water and photoassimilate translocation pathways to and within nodules. The present study shows that in damaged roots LYCH moves apoplastically through the vascular elements but it was not detected within the nodule vascular bundles. In intact roots, the outer cortex was strongly labeled but the dye was not present in the interior of intact root nodules. The inwards movement of LYCH was halted in the endodermis. When the dye was introduced into a damaged nodule by infiltration, it spread only in the cell walls and the intercellular spaces up to the inner cortex. Our research showed that in addition to the outer cortex, the inner tissue containing bacteroid-infected cells is also an apoplastic domain. Our results are consistent with the hypothesis that nodules do not receive water from the xylem but get it and photoassimilates from phloem. A comparison between using LYCH and LYCH followed by glutaraldehyde fixation indicates that glutaraldehyde is responsible for fluorescence of some organelles within root nodule cells. The influence of the fixation on nodule fluorescence has not been reported before but must be taken into consideration to avoid errors. An attempt was made to follow carboxyfluorescein (6(5) CF) translocation from leaflets into roots and root nodules. In root nodules, CF was present in all or a couple of vascular bundles (VB), vascular endodermis and some adjacent cells. The leakage of CF from the VBs was observed, which suggests symplastic continuity between the VBs and the nodule parenchyma. The lack of CF in inner tissue was observed. Therefore, photoassimilate entry to the infected region of nodule must involve an apoplastic pathway.

Structural changes in Medicago truncatula root nodules caused by short-term aluminum stress.

Aluminum in the form of Al3+ is one of the most toxic heavy metal pollutants in nature and its effects are primarily root-related. Roots of Medicago truncatula exposed to 50 µM of AlCl3 for 2 h and 24 h were examined by light and electron microscopy. Changes in the appearance of the host cells, infection threads and bacteroidal tissue occurred during the first 2 h of Al stress. Microscopic observations showed that aluminum: (1) induced thickening of plant cell and infection threads (ITs) walls, (2) stimulated IT enlargement, (3) caused disturbances in bacterial release from the ITs, (4) modified cell vacuolation and induced synthesis of granular material and its deposition in the cytoplasm, (5) and caused structural alterations of organella and bacteroids.

Vacuolar organization in the nodule parenchyma is important for the functioning of pea root nodules.

Different models have been proposed to explain the operation of oxygen diffusion barrier in root nodules of leguminous plants. This barrier participates in protection of oxygen-sensitive nitrogenase, the key enzyme in nitrogen fixation, from inactivation. Details concerning structural and biochemical properties of the barrier are still lacking. Here, the properties of pea root nodule cortical cells were examined under normal conditions and after shoot removal. Microscopic observations, including neutral red staining and epifluorescence investigations, showed that the inner and outer nodule parenchyma cells exhibit different patterns of the central vacuole development. In opposition to the inner part, the outer parenchyma cells exhibited vacuolar shrinkage and formed cell wall infoldings. Shoot removal induced vacuolar shrinkage and formation of infoldings in the inner parenchyma and uninfected cells of the symbiotic tissue, as well. It is postulated that cells which possess shrinking vacuoles are sensitive to the external osmotic pressure. The cells can give an additional resistance to oxygen diffusion by release of water to the intercellular spaces.Immunolocalization studies proved higher expression of endo-ß-1,4-glucanases within expanding cells of the outer cortex of pea nodules comparing with nodule endodermis or nodule parenchyma, so it is suggested that (1) endo-glucanases are involved in growth related modifications of cell walls and (2) enlarged cells decrease nodule conductance to oxygen.

[Risk factors of pelvic organ prolapsed in women qualified to reconstructive surgery--the Polish multicenter study]. / Czynniki ryzyka defektów dna miednicy u kobiet zakwalifikowanych do operacji rekonstrukcyjnych--polskie badanie wieloosrodkowe.

AIM OF STUDY: To evaluate the prevalence rate of various pelvic floor disorders among patients treated in 8 academic centers in Poland due to pelvic organ prolapse (POP). MATERIAL AND METHODS: The study group consisted of 717 women scheduled for reconstructive surgery due to POP. Risk factors, functional abnormalities along with symptoms affecting quality of life, were assessed by means of disease specific questionnaire. The stage of the disease was assessed after gynecological examination using POP-Q score. RESULTS: The mean age of affected women with POP was 61,25 years (median 61), and mean BMI--27.62 (median--27.29). 80% of women were menopausal. Mean time of symptoms related to disease was 65,6 months; whereas the time relapsed from first doctor diagnosis of POP to hospital admission was 50.6 months. 97.4% affected women were multiparous. Only 1.21% women with POP were nulliparous. Family history of prolapse was found in 13.4% of patients, whereas familial positive history of urinary incontinence was 10%. Lower urinary tract symptoms (LUTS) among the analyzed group were as follows: frequency--almost 50%, urgency 32.2%, feeling of improper voiding -29,6% and voiding difficulty -17.7%. Functional disorders of lower bowel were found in 43% of patients and the most prevalent symptom was constipation (31%), followed by empting difficulty (12%), dyschesia (9%), and urge stool empting (7.7%). Cardiovascular diseases were found among 43% of respondents, whereas pulmonary diseases with chronic coughing were present in 20% of the analyzed population. Subjective POP symptoms reported by women were as follows: feeling of heaviness in lower abdomen--378%, perineal pain--27.8%, lumbosacral pain-34.2%, and abdominal pain--28.4%. Female sexual disorders were reported by 9,8% women and dyspareunia was found in 7.6% of responders. POP was the main reason for sexual abstinence only in 1 out of 10 patients. More than 30% of patients from the study group underwent previously pelvic surgery due to various reasons. POP related quality of life measured by VAS (Visual Analogue Scale) was 61.4 points (median--60). The most common finding during gynecological examination was cystocele--96.5%, followed by rectoenterocele--92.7%, and central defect--79%. Mean POP quantification was stage III in POP-Q scale. LUTS symptoms (urinary incontinence, urgency and voiding difficulties) were present among 81% of patients whereas lower gastrointestinal disorders (constipation, fecal incontinence, dyschesia) were found in 43% of women affected by POP. CONCLUSIONS: Mean delay time from objective POP diagnosis until decision concerning surgical treatment was more than 5 years. The most common risk factors associated with POP were: multiparity with vaginal deliveries, obesity and aging. The most common defect found among patients with POP was cystocele, followed by rectoenterocele and central defect however most patients presented with advanced combined defects.

Alteration of O-specific polysaccharide structure of symbiotically defective Mesorhizobium loti mutant 2213.1 derived from strain NZP2213.

Mesorhizobium loti mutant 2213.1 derived from the wild-type strain NZP2213 by Tn5 mutagenesis showed impaired effectiveness of symbiosis with the host plant Lotus corniculatus (Turska-Szewczuk et al., 2007 Microbiol Res, in press). The inability of lipopolysaccharide (LPS) isolated from the mutant 2213.1 strain or de-O-acetylated LPS of the parental cells to inactivate phage A1 particles implicated alterations in the LPS structure. The O-specific polysaccharide of the mutant was studied by chemical analyses along with (1)H and (13)C NMR spectroscopy, which clearly confirmed alterations in the O-chain structure. 2D NMR data showed that the mutant O-polysaccharide consists of a tetrasaccharide repeating unit containing non-substituted as well as O-acetylated or O-methylated 6-deoxytalopyranose residues. Additionally, an immunogold assay revealed a reduced number of gold particles on the mutant bacteroid cell surface, which could result from both a diminished amount of an O-antigenic determinant in mutant LPS and modifications of structural epitopes caused by alterations in O-acetylation or O-methylation of sugar residues. Western immunoblot assay of alkaline de-O-acetylated lipophilic M. loti NZP2213 LPS showed no reactivity with homologous serum indicating a role of O-acetyl groups in its O-specificity.

Surgical treatment of stress urinary incontinence using the tension-free vaginal tape-obturator system (TVT-O) technique.

OBJECTIVE: The purpose of the research was to provide a review of the efficacy of the TVT-O technique for the surgical treatment of stress urinary incontinence (SUI) and to assess surgical and postsurgical complications related to this technique. STUDY DESIGN: An initial assessment was carried out on 44 women who underwent TVT-O surgery between 16 September 2004 and 1 February 2005. The follow-ups after 3 and 12 months were attended by 37 and 35 patients, respectively. All 44 patients were included for the statistical estimation of intra- and postoperative complications, whereas improvement in the quality of life was assessed only in those patients who came for a follow-up visit. To assess the efficacy of the treatment, the participants were surveyed using the King questionnaire on the day preceding surgery and during a follow-up visit 3 and 12 months after surgery. The participants whose scores from the two questionnaires changed > or =90% were deemed to be cured. A considerable improvement in quality of life was recorded when the score was 89-75%. With scores of 74-50%, there was a reduction in SI symptoms. However, when the score was 50-0%, no improvement in quality of life was reported, and in participants with scores <0% the quality of life deteriorated. Statistical analysis was carried out using the Statistical Package for Social Sciences (SPSS) V. 10.0, with the Spearman correlation and Chi-squared tests. The results were considered statistically significant when P<0.05. RESULTS: After 12 months, total cure was achieved in 15 participants (42.8%), significant improvement was noted in 6 (17.1%), SUI symptoms abated in 4 (11.4%), no improvement was noted in 7 (20%), and quality of life deteriorated in 3 (8.7%). CONCLUSION: TVT-O surgery is an efficient and reasonably safe method of SUI treatment in women. The ease of use, short duration of surgery and hospitalisation, minor postsurgical discomfort and a small proportion of complications make this method acceptable to patients. With regard to the results of treatment, additional patients should be analysed for a longer period of time.

[HELLP syndrome complicated by liver rupture]. / Pekniecie watroby w zespole HELLP.

The object of our study was the liver rupture as a complication of HELLP syndrome. We described a case of 27-year-old primigravida who underwent the cesarean section because of HELLP syndrome, followed by four laparotomies, due to capsular hematoma and liver rupture. Surgery with packing, argon coagulation or embolization of hepatic artery remain the only treatment for subcapsular hematoma and liver rupture. The main issue is to state the early diagnosis of HELLP syndrome because its clinical presentation at the beginning is very unclear and diagnosis is often delayed. It is important because the morbidity and mortality rates associated with the syndrome have been reported to be as high as 25 percent.

Effect of yeast CTA1 gene expression on response of tobacco plants to tobacco mosaic virus infection.

The response of tobacco (Nicotiana tabacum L. cv Xanthi-nc) plants with elevated catalase activity was studied after infection by tobacco mosaic virus (TMV). These plants contain the yeast (Saccharomyces cerevisiae) peroxisomal catalase gene CTA1 under the control of the cauliflower mosaic virus 35S promoter. The transgenic lines exhibited 2- to 4-fold higher total in vitro catalase activity than untransformed control plants under normal growth conditions. Cellular localization of the CTA1 protein was established using immunocytochemical analysis. Gold particles were detected mainly inside peroxisomes, whereas no significant labeling was detected in other cellular compartments or in the intercellular space. The physiological state of the transgenic plants was evaluated in respect to growth rate, general appearance, carbohydrate content, and dry weight. No significant differences were recorded in comparison with non-transgenic tobacco plants. The 3,3'-diaminobenzidine-stain method was applied to visualize hydrogen peroxide (H(2)O(2)) in the TMV infected tissue. Presence of H(2)O(2) could be detected around necrotic lesions caused by TMV infection in non-transgenic plants but to a much lesser extent in the CTA1 transgenic plants. In addition, the size of necrotic lesions was significantly bigger in the infected leaves of the transgenic plants. Changes in the distribution of H(2)O(2) and in lesion formation were not reflected by changes in salicylic acid production. In contrast to the local response, the systemic response in upper noninoculated leaves of both CTA1 transgenic and control plants was similar. This suggests that increased cellular catalase activity influences local but not systemic response to TMV infection.