The Water to Water Cycles in Microalgae.

In oxygenic photosynthesis, light produces ATP plus NADPH via linear electron transfer, i.e. the in-series activity of the two photosystems: PSI and PSII.

Regulation of electron transport in microalgae.

Unicellular algae are characterized by an extreme flexibility with respect to their responses to environmental constraints. This flexibility probably explains why microalgae show a very high biomass yield, constitute one of the major contributors to primary productivity in the oceans and are considered a promising choice for biotechnological applications. Flexibility results from a combination of several factors including fast changes in the light-harvesting apparatus and a strong interaction between different metabolic processes (e.

The onset of NPQ and Deltamu(H)+ upon illumination of tobacco plants studied through the influence of mitochondrial electron transport.

The relationship between the development of photoprotective mechanisms (non-photochemical quenching, NPQ), the generation of the electrochemical proton gradient in the chloroplast and the capacity to assimilate CO(2) was studied in tobacco dark-adapted leaves at the onset of illumination with low light. These conditions induce the generation of a transient NPQ, which relaxes in the light in parallel with the activation of the Calvin cycle. Wild-type plants were compared with a CMSII mitochondrial mutant, which lacks the respiratory complex I and shows a delayed activation of photosynthesis.

The role of respiration in the activation of photosynthesis upon illumination of dark adapted Chlamydomonas reinhardtii.

It is reported that O(2) is required for the activation of photosynthesis in dark adapted Chlamydomonas reinhardtii in State 1, under low light intensity. The concentration of dissolved O(2) of ca. 9 microM is sufficient to saturate the requirement.

Micronuclei frequency induced by bleomycin in human peripheral lymphocytes: correlating BLHX polymorphism with mutagen sensitivity.

Mutagen sensitivity assay, by measuring chromosome damage induced by an in vitro treatment of peripheral lymphocytes with bleomycin, has been proposed as a biomarker for assessing cancer susceptibility. Recently, a single nucleotide polymorphism (SNP A1450G) of the gene for bleomycin hydrolase (BLHX), a specific neutral cysteine protease able to metabolise bleomycin, was proposed as a plausible candidate to variation in mutagen sensitivity. To shed more light on the effect of BLHX genotype on the expression of chromosome damage induced in vitro by bleomycin, we determined mutagen sensitivity for 45 non-smoker healthy volunteers.

Relevance of apple consumption for protection against oxidative damage induced by hydrogen peroxide in human lymphocytes.

In a single-dosing crossover study, we investigated the ability of apple fruit consumption to protect human lymphocytes against peroxide-induced damage to DNA. Six healthy, non-smoking male volunteers were placed for 2d on an antioxidant-poor (AP) diet. After 48h of AP diet, the volunteers were required to consume a homogenate obtained from 600g of red delicious unpeeled apples or water (500 ml); blood samples were collected 0, 3, 6 and 24 h post-consumption.

Perturbation of cytochrome P450, generation of oxidative stress and induction of DNA damage in Cyprinus carpio exposed in situ to potable surface water.

Epidemiological evidence suggests a link between consumption of chlorinated drinking water and various cancers. Chlorination of water rich in organic chemicals produces carcinogenic organochlorine by-products (OBPs) such as trihalomethanes and haloacetic acids. Since the discovery of the first OBP in the 1970s, there have been several investigations designed to determine the biological effects of single chemicals or small artificial OBP combinations.

Photosynthesis research in Italy: a review.

This historical review was compiled and edited by Giorgio Forti, whereas the other authors of the different sections are listed alphabetically after his name, below the title of the paper; they are also listed in the individual sections. This review deals with the research on photosynthesis performed in several Italian laboratories during the last 50 years; it includes research done, in collaboration, at several international laboratories, particularly USA, UK, Switzerland, Hungary, Germany, France, Finland, Denmark, and Austria. Wherever pertinent, references are provided, especially to other historical papers in Govindjee et al.

Simultaneous HPLC analysis, with isocratic elution, of glycyrrhizin and glycyrrhetic acid in liquorice roots and confectionery products.

Glycyrrhizin (1), the main active principle of Glycyrrhiza glabra (liquorice) roots, is extensively used in herbal medicines, in pharmaceutical preparations and confectionery products. A feasible and reliable method which allows the simultaneous analysis of 1 and its aglycone, 18beta-glycyrrhetic acid (2), by means of an isocratic HPLC procedure is described. The system uses a C8 column as the stationary phase, and a mixture of acetonitrile, methanol, water and glacial acetic acid as the mobile phase.

Metabolic Flexibility of the Green Alga Chlamydomonas reinhardtii as Revealed by the Link between State Transitions and Cyclic Electron Flow.

In this Review we focus on the conversion of linear photosynthetic electron transport from water to NADP to the cyclic pathway around Photosystem I in the green alga Chlamydomonas reinhardtii. We discuss the strict relationship that exists between the changes in pathways of electron transport and state transitions, i.e.

Separation and analysis of glycyrrhizin, 18beta-glycyrrhetic acid and 18alpha-glycyrrhetic acid in liquorice roots by means of capillary zone electrophoresis.

Glycyrrhizin is the main active compound of Glycyrrhiza glabra root extracts; according to recent studies, glycyrrhizin and its aglycon, glycyrrhetic acid, have interesting therapeutic properties. A new capillary electrophoretic method has been developed for the separation and quantification of glycyrrhizin, beta-glycyrrhetic acid and its isomer a-glycyrrhetic acid. Separation of the analytes was achieved in less than 3 min on a fused silica capillary, by injecting the samples at the short end of the capillary (effective length: 8.

Use of the Comet test and micronucleus assay on human white blood cells for in vitro assessment of genotoxicity induced by different drinking water disinfection protocols.

Surface water disinfection can lead to the formation of mutagenic/carcinogenic by-products derived from reactions with naturally occurring inorganic compounds. We investigated the feasibility and potential usefulness of an integrated approach to genotoxicity analysis of drinking water. The approach employed the Comet and micronucleus (MN) assays to evaluate the DNA and chromosomal damage produced by water extracts in human blood cells.

Pericardial metastases in a long-surviving patient with sigmoid carcinoma.

Cardiac metastases are rare in patients affected by colorectal cancer. This is the case of a woman who underwent a colon resection because of a metastatic sigmoid carcinoma, that survived for more than 6 years and died for malignant pericardial effusion.

Two cases of secondary soft tissue sarcomas after radiotherapy and radiochemotherapy.

Background: The development of secondary soft tissue sarcomas after chemo-radiotherapy is a rare and little known event, but its frequency is increasing.

Patients And Methods: We report two cases of secondary soft tissue sarcomas. The first is the case of a 51-year-old woman treated for Hodgkin's disease with chemotherapy and radiotherapy 15 years before she developed a high-grade malignant pleural sarcoma.

Micronuclei in humans induced by exposure to low level of ionizing radiation: influence of polymorphisms in DNA repair genes.

Understanding the risks deriving from protracted exposure to low doses of ionizing radiation has remarkable societal importance in view of the large number of work settings in which sources of IR are encountered. To address this question, we studied the frequency of micronuclei (MN), which is an indicator of DNA damage, in a population exposed to low levels of ionizing radiation and in matched controls. In both exposed population and controls, the possible influence of single nucleotide polymorphisms in XRCC1, XRCC3 and XPD genes on the frequency of micronuclei was also evaluated.

State transitions in Chlamydomonas reinhardtii. The role of the Mehler reaction in state 2-to-state 1 transition.

The light intensity-dependent transition to state 1 of dark-adapted anaerobic state 2 Chlamydomonas reinhardtii cells is stimulated by oxygen and by other electron acceptors for photosystem I, such as oxaloacetate and methylviologen. This suggests that the transition to state 1 requires the oxidation of the intersystem chain by photosystem I photochemistry. On the other hand, the mere oxidation in the dark of the chain-by addition of O2-leads only to a slow and incomplete transition.

A molecular epidemiological approach to health risk assessment of urban air pollution.

The ambient air of urban centres is polluted with potentially toxic chemicals mostly arising from the combustion or fuels used for transport. Among these compounds, benzene raises particular concern due to its haematoxicity and leukaemogenic risks. Although limits of benzene in air have been established in the European Union (5 microg/m(3)), individual exposure levels--and therefore risk estimates--cannot merely be extrapolated from environmental concentrations.

Spectrum of chromosomal aberrations in peripheral lymphocytes of hospital workers occupationally exposed to low doses of ionizing radiation.

Chromosome aberrations frequency was estimated in peripheral lymphocytes from hospital workers occupationally exposed to low levels of ionizing radiation and controls. Chromosome aberrations yield was analyzed by considering the effects of dose equivalent of ionizing radiation over time, and of confounding factors, such as age, gender and smoking status. Frequencies of aberrant cells and chromosome breaks were higher in exposed workers than in controls (P = 0.

In vivo changes of the oxidation-reduction state of NADP and of the ATP/ADP cellular ratio linked to the photosynthetic activity in Chlamydomonas reinhardtii.

The ATP/ADP and NADP/NADPH ratios have been measured in whole-cell extract of the green alga Chlamydomonas reinhardtii, to understand their availability for CO(2) assimilation by the Calvin cycle in vivo. Measurements were performed during the dark-light transition of both aerobic and anaerobic cells, under illumination with saturating or low light intensity. Two different patterns of behavior were observed: (a) In anaerobic cells, during the lag preceding O(2) evolution, ATP was synthesized without changes in the NADP/NADPH ratio, consistently with the operation of cyclic electron flow.

Micronuclei frequencies in hospital workers occupationally exposed to low levels of ionizing radiation: influence of smoking status and other factors.

In the context of a medical surveillance program aimed at preventing cancer risk from exposure to ionizing radiation, we investigated chromosomal damage in peripheral lymphocytes from 37 hospital workers exposed to low levels of ionizing radiation and 37 controls. The micronuleus (MN) assay was used as a biomarker of genetic damage. The influence of confounding factors like smoking status, age and gender was investigated by multiple regression analysis.

Involvement of state transitions in the switch between linear and cyclic electron flow in Chlamydomonas reinhardtii.

The energetic metabolism of photosynthetic organisms is profoundly influenced by state transitions and cyclic electron flow around photosystem I. The former involve a reversible redistribution of the light-harvesting antenna between photosystem I and photosystem II and optimize light energy utilization in photosynthesis whereas the latter process modulates the photosynthetic yield. We have used the wild-type and three mutant strains of the green alga Chlamydomonas reinhardtii--locked in state I (stt7), lacking the photosystem II outer antennae (bf4) or accumulating low amounts of cytochrome b6f complex (A-AUU)--and measured electron flow though the cytochrome b6f complex, oxygen evolution rates and fluorescence emission during state transitions.

Biomarkers to assess the genetic damage induced by alcohol abuse in human lymphocytes.

Alcohol abuse is a major risk factor for cancer of the upper alimentary tract, the upper respiratory tract, and liver. Chromosome damage is used as early effect biomarker in the surveillance of human exposure to genotoxic carcinogens. In the present study, two genetic markers, namely chromosome aberrations (CAs) and micronuclei (MN), were used to evaluate genetic damage in peripheral lymphocytes from 20 alcoholics, 20 abstinent alcoholics, and 20 controls.