Nutraceutical value and safety of tomato fruits produced by mycorrhizal plants.

Tomato fruit has assumed the status of 'functional food' due to the association between its consumption and a reduced likelihood of certain types of cancers and CVD. The nutraceutical value of tomatoes can be affected by the cultivation conditions, e.g. the phytochemical content of the fruits may increase with the establishment of beneficial mycorrhizal symbioses in the plants. A multidisciplinary study was carried out to gain knowledge on the antioxidant, oestrogenic/anti-oestrogenic and genotoxic activity of tomato fruits produced by mycorrhizal plants. The present results showed that the symbiosis positively affected the growth and mineral nutrient content of tomato plants and enhanced the nutritional and nutraceutical value of tomato fruits through modifications of plant secondary metabolism, which led to increased levels of lycopene in fruits obtained from mycorrhizal plants, compared with controls. Moreover, such changes did not result in the production of mutagenic compounds, since tomato extracts induced no in vitro genotoxic effects. Fruit extracts, both hydrophilic and the lipophilic fractions, originating from mycorrhizal plants strongly inhibited 17-ß-oestradiol-human oestrogen receptor binding, showing significantly higher anti-oestrogenic power compared with controls. The present study shows that beneficial plant symbionts, such as mycorrhizal fungi, can lead to the production of safe and high-quality food, which is an important societal issue strongly demanded by both consumers and producers.

Cellular events involved in survival of individual arbuscular mycorrhizal symbionts growing in the absence of the host

A survival strategy operating in the absence of the host was shown in obligately biotrophic arbuscular mycorrhizal (AM) symbionts. When no host-derived signals from the surrounding environment were perceived by germinating spores, fungal hyphae underwent a programmed growth arrest and resource reallocation, allowing long-term maintenance of viability and host infection capability. The early stages of mycelial growth of AM fungi were studied by a combination of time-lapse and video-enhanced light microscopy, image analysis, and immunodetection, with the aim of acquiring knowledge of cell events leading to the arrest of mycelial growth. The time-course of growth arrest was resolved by precisely timing the growth rate and magnitude of the mycelium originating from individual spores of Glomus caledonium. Extensive mycelial growth was observed during the first 15 days; thereafter, fungal hyphae showed retraction of protoplasm from the tips, with formation of retraction septa separating viable from empty hyphal segments. This active process involved migration of nuclei and cellular organelles and appeared to be functional in the ability of the fungus to survive in the absence of a host. Immunodetection of cytoskeletal proteins, metabolic activity, and the retention of infectivity of germinated spores confirmed the developmental data. The highest amounts of tubulins were detected when hyphal growth had ceased but when retraction of protoplasm was most active. This was consistent with the role of the cytoskeleton during protoplasm retraction. Succinate dehydrogenase activity in hyphae proximal to the mother spore was still detectable in 6-month-old mycelium, which remained viable and able to form appressoria and produce symbiotic structures.

Differential hyphal morphogenesis in arbuscular mycorrhizal fungi during pre-infection stages.

Roots of host plants elicit a local change in morphology in the hyphae of arbuscular mycorrhizal fungi, prior to the formation of appressoria. The elicited hyphae switch from their original branching pattern and apical dominance to differentiate in a new irregular, septate branching pattern with reduced inter-hyphal spacing. The extensive hyphal development associated with roots of host plants was shown to be due to the differential growth pattern described, and to precede the further cascade of events leading to appressorium formation and the development of a functional symbiosis.

The antifungal Dm-AMP1 protein from Dahlia merckii expressed in Solanum melongena is released in root exudates and differentially affects pathogenic fungi and mycorrhizal symbiosis.

• Transformed aubergine plants constitutively expressing the Dm-AMP1 antimicrobial defensin (from Dahlia merckii) were generated and characterized. • Transgenic plants were selected on kanamycin and screened by polymerase chain reaction analysis. The expression of Dm-AMP1 in plant tissues and its release in root exudates were detected by Western blot analyses. Dm-AMP1 localization was performed by immunohistochemical experiments. • Dm-AMP1 expression ranged from 0.2% to 0.48% of total soluble proteins in primary transformants and from 0.16% to 0.66% in F2 plants. Transformed clones showed resistance to the pathogenic fungus Botrytis cinerea, whose development on leaves was reduced by 36-100%, with respect to controls. The protein was released in root exudates of the transformed plants and was active in reducing the growth of the co-cultured pathogenic fungus Verticillium albo-atrum, whereas it did not interfere with recognition responses and symbiosis establishment by the arbuscular mycorrhizal fungus Glomus mosseae. • Dm-AMP1 transformants may represent a useful model to study the interactions between genetically modified plants and pathogenic fungi or beneficial nontarget microorganisms.

The analysis of the joint effect of substances on reversion systems and the assessment of antimutagenicity.

The statistical methods for the analysis of mutagenicity and carcinogenicity underwent considerable theoretical-practical development following the need for assessing the mutagenic and carcinogenic potential of substances. Antimutagenicity is investigated through the analysis of respondents in dose-response assays, when two different molecules are administered separately and as a mixture to a respondent system. When the number of respondent units is high, and doses are orthogonal, it is possible to apply simple models such as analysis of variance. This is not always possible or common, and alternative approaches have been developed, based on multiple regression and on tables of proportions. In this work, some of the most frequently used methods for the assessment of joint responses are reviewed, particularly those based on multiple regression, such as the method of Shaeffer et al. and the method of Hass et al. In order to illustrate these methods, joint responses of perylene and cyclopentapyrene, of N-acetylcysteine and dinitropyrene, and of N-acetylcysteine and extracts from diesel exhausts were analyzed. An antagonistic effect of perylene on the action of CPP was detected by the algorithm of Shaeffer et al. The effect is not multiplicative, i.e., it is not proportional to the product of doses. The antimutagenic effect of N-acetylcysteine on dinitropyrene is multiplicative, as detected by the method of Hass et al. The latter reveals that the inhibition by N-acetylcysteine on the mutagenic effect of extracts from diesel exhausts is also multiplicative.

Effects derived from long-term low-level chromium exposure in ferro-alloy metallurgy. Study of absorption and renal function in workers.

Ferro-chromium production is based on the use of chromium oxide (III) and it is generally accepted that chromium in this form is not able to cross biological barriers. However, the data on the toxic and carcinogenic effects of hexavalent chromium in man are now firmly established. Some studies have questioned these data, calling for a clarification as to whether exposure to trivalent chromium can also produce human effects, perhaps with different latency time. A study was carried out on the exposure conditions (type and degree) in a ferro-chromium foundry that had been in operation since 1972. The absorption levels in the working population of the foundry, and the possible toxic effects on the kidney have been investigated. A total of 236 workers (142 employed in production departments, 33 office workers and 61 sub-contractor employees) were examined with measurement of the indicators of dose (urinary-chromium) and of effect on the kidney (albumin, retinol binding protein, and renal tubular epithelium antigens in the urine). Environmental hygiene measurements showed relatively low values of total chromium in the air (always less than 0.160 mg/m3). Hexavalent chromium was absent or, if present, at levels below the sensitivity of the analytical method used (0.001 mg/m3). The values of urinary chromium measured at the beginning and at the end of the working day and at the end of the work shift were always less than 5 micrograms/g creatinine, which has been proposed as a biological limit in chromium exposure. However, differences were observed between groups of subjects employed on different jobs, which is indicative of an absorption process varying according to the degree of exposure. The indicators of effect did not reveal any renal impairment, even early, that could be attributed to the toxic action of chromium.

Potentiation of occupational carbon tetrachloride toxicity by ethanol abuse.

1. Two separate cases of acute occupational poisoning following exposure to vapours of a fire extinguishing liquid are described. Analytical, clinical, pathological and toxicological data leave little doubt that toxicity was due, in both cases, to inhalation of carbon tetrachloride present at high concentrations ( > 15% and 78% by weight, respectively) in the fire extinguishing liquid. 2. Both subjects were admitted to hospital, 4 and 8 days after exposure, respectively, and developed severe hepato-nephrotoxicity with hepatomegaly, increased values of serum transaminases, blood urea nitrogen (BUN), creatinine, gamma-glutamyl-transpeptidase (gamma-GT), bilirubin and uric acid and, finally, anuria. They recovered in about three to four weeks, after several haemodialytic sessions. 3. Interestingly, in both cases the other workers exposed under the same conditions and for the same period of time as the two patients showed no signs or symptoms of toxicity. The reason for the observed different susceptibility to CCl4 is attributable to an abnormally high ethanol abuse by the two workers, as reported in the clinical records and confirmed by their relatives and colleagues (120 and 250 g per day, respectively). Daily ethanol intake by the coworkers was less than 50 g for all subjects. 4. Although the potentiating effect of ethanol on the toxicity of CCl4 is well known in experimental animals, as a result of cytochrome P-450 induction, direct evidence in humans reported in the literature so far was limited by the lack of information, in all published reports, on the presence or absence of effects in non-alcoholic exposed "controls', when these were present.

Chemotropism in the arbuscular mycorrhizal fungus Glomus mosseae.

In this work, we report the occurrence of chemotropism in the arbuscular mycorrhizal (AM) fungus Glomus mosseae. Fungal hyphae were able to respond to host-derived signals by reorienting their growth towards roots and to perceive chemotropic signals at a distance of at least 910 microm from roots. In order to reach the source of chemotropic signals, hyphal tips crossed interposed membranes emerging within 1 mm from roots, eventually establishing mycorrhizal symbiosis. The specificity of chemotropic growth was evidenced by hyphal growth reorientation and membrane penetration occurring only in experimental systems set up with host plants. Since pre-symbiotic growth is a critical stage in the life cycle of obligate AM fungal symbionts, chemotropic guidance may represent an important mechanism functional to host root location, appressorium formation and symbiosis establishment.

Impact of Bt corn on rhizospheric and soil eubacterial communities and on beneficial mycorrhizal symbiosis in experimental microcosms.

A polyphasic approach has been developed to gain knowledge of suitable key indicators for the evaluation of environmental impact of genetically modified Bt 11 and Bt 176 corn lines on soil ecosystems. We assessed the effects of Bt corn (which constitutively expresses the insecticidal toxin from Bacillus thuringiensis, encoded by the truncated Cry1Ab gene) and non-Bt corn plants and their residues on rhizospheric and bulk soil eubacterial communities by means of denaturing gradient gel electrophoresis analyses of 16S rRNA genes, on the nontarget mycorrhizal symbiont Glomus mosseae, and on soil respiration. Microcosm experiments showed differences in rhizospheric eubacterial communities associated with the three corn lines and a significantly lower level of mycorrhizal colonization in Bt 176 corn roots. In greenhouse experiments, differences between Bt and non-Bt corn plants were detected in rhizospheric eubacterial communities (both total and active), in culturable rhizospheric heterotrophic bacteria, and in mycorrhizal colonization. Plant residues of transgenic plants, plowed under at harvest and kept mixed with soil for up to 4 months, affected soil respiration, bacterial communities, and mycorrhizal establishment by indigenous endophytes. The multimodal approach utilized in our work may be applied in long-term field studies aimed at monitoring the real hazard of genetically modified crops and their residues on nontarget soil microbial communities.

Comparison of Photomorphogenic Responses to UV Light in Red and White Cabbage (Brassica oleracea L.).

Photoinhibition of hypocotyl growth in white cabbage (Brassica oleracea L., cv "Bianco Brunswick") is controlled by UV absorbing receptor(s) and the phytochrome system, while in red cabbage (cv "Rosso Olandese tardivo invernale") phytochrome can act without any requirement for the action of a specific UV receptor. Similar results have been obtained for the photoregulation of anthocyanin production. Twenty-four hour preirradiations with UV light or 692 nanometers light lead to the same increase in responsiveness of the system toward Pfr in a following dark period, suggesting a phytochrome promotion of subsequent light induction for both.

N-acetylcysteine inhibits diesel extract mutagenicity in the Ames test and SCE induction in human lymphocytes.

N-Acetylcysteine (NAC) has been reported to decrease genotoxicity induced by several mutagens. In this paper, the desmutagenic effect of NAC on a complex mixture, such as diesel extract, has been analyzed. Studies have been carried out in vitro with the Ames test (reverse mutations on TA98, TA100, and TA104 strains) and sister chromatid exchanges assay (SCE) in human lymphocytes. NAC inhibits diesel genotoxicity in both assays. NAC also inhibits the mutagenicity of 1,8-dinitropyrene (1,8-DNP) and 1-nitropyrene (1-NP) known to be present in diesel exhaust and to be activated by cellular O-transacetylases and nitropyrene reductases. NAC inhibits also the induction of SCE in human lymphocytes by diesel extract. These results, and those obtained by the preincubation of NAC with cells, suggest that the inhibition also takes place inside the cell.

Adhesion to hyphal matrix and antifungal activity of Pseudomonas strains isolated from Tuber borchii ascocarps.

Pseudomonas spp. isolates from Tuber borchii ascocarps, known to be able to produce phytoregulatory and biocontrol substances in pure culture, were used to perform studies on their possible physiological role in nature. Antimycotic activity was confirmed against fungal contaminants isolated from the ascocarps, suggesting that populations associated with Tuber borchii fruit bodies may play a role in the maintenance of ascocarp health. Fifty-five percent of strains tested were also able to release metabolites which affected T. borchii mycelial growth and morphogenesis in culture. On the contrary, growth of the arbuscular mycorrhizal fungus Glomus mosseae and the ectomycorrhizal fungus Laccaria bicolor, putative competitors of Tuber for mycorrhizal infection sites on roots, was not influenced by the presence of any bacterial strain. The possibility that these bacteria, which show antifungal activity and fungal growth modulation activities, might be incorporated in the developing ascocarp by means of their preferential adhesion to Tuber mycelium is discussed.

[Cross-over epidemiologic study of symptoms and respiratory function in workers at a furniture factory]. / Indagine epidemiologica trasversale sui sintomi e la funzione respiratoria nei lavoratori di un mobilificio.

An epidemiological survey on symptoms and diseases (collected with CNR standardized questionnaire) and on lung function (forced vital capacity and derived indexes; CO diffusing capacity) has been carried on in workers of a furniture plant in Arezzo. Significantly higher prevalence rates of cough in smokers than in non smokers, and of cough, phlegm, wheeze in non smoker workers than in the control group from a general population sample were present. A not significant relationship of symptoms and working years was also found. Lung function indices were in the normal range; smokers had significantly lower values than non smokers. A lower FEV1%, after adjusting for age and smoking, was shown by subjects with more working years. Thus, in a modern furniture plant the risk of adverse health effect seems to be slight: this conclusion may be confirmed by the ongoing longitudinal survey.

Cytogenetic biomonitoring of styrene-exposed plastic boat builders.

Earlier studies have produced evidence for an association between work-related styrene exposure and cytogenetic damage, while more recent studies have failed to show such an association. In the present study, chromosome aberrations (CA) and sister chromatid exchanges (SCE) were measured in peripheral blood lymphocytes of 46 male workers employed in a fiber-reinforced plastic boat building factory and exposed to styrene. Two groups of 23 workers each, characterized by different exposure levels (ranges: 2-120 mg/m3 and 86-1389 mg/m3 ambient air) were studied, fifty-one controls matched by sex, age and smoking habits were included. Randomized blood samples were analyzed for cytogenetic damage separately in two laboratories. Interlaboratory differences in the scoring of CA and SCE were noted. However, increases of the considered cytogenetic endpoints in exposed vs control groups were consistently observed in both laboratories. Multivariate statistical analysis of pooled data revealed increases of CA ranging between 19% (RR = 1.19; 95% C.I., 0.80-1.78; chromatid-type aberrations, low exposure group) and 144% (RR = 2.44; 95% C.I., 1.26-4.70; chromosome-type aberrations, high exposure group). Parallel excess of SCE in styrene exposed workers was also observed, although at a lesser extent (RR = 1.22; 95% C.I., 1.05-1.43, low exposure group; RR = 1.26; 95% C.I., 1.07-1.47, high exposure group). These findings suggest the presence of a causal association between occupational exposure to styrene and cytogenetic damage in the plastic boat building factory that was the object of the study.