Characterization of the cryptic interspecific hybrid Lemna×mediterranea by an integrated approach provides new insights into duckweed diversity.

Lemnaceae taxonomy is challenged by the particular morphology of these tiny free-floating angiosperms. Although molecular taxonomy has helped clarify the phylogenetic history of this family, some inconsistency with morphological data leads to frequent misclassifications in the genus Lemna. Recently, the finding that Lemna japonica is an interspecific hybrid between Lemna minor and Lemna turionifera provided a clear explanation for one such taxonomic question. Here we demonstrated that L. minor is also capable of hybridizing with Lemna gibba, generating a cryptic but widespread taxon in the Mediterranean area. The nothotaxon Lemna ×mediterranea is described and compared with clones of the putative parental species L. minor and L. gibba. Genetic analysis by nuclear and plastid markers, as well as genome size measurement, revealed that two different cytotypes, diploid and triploid, originated by at least two independent hybridization events. Despite high overall similarity, morphometrical, physiological, and biochemical analyses showed an intermediate position of L. ×mediterranea between its parental species in most qualitative and quantitative characters, and also separation of the two hybrid cytotypes by some criteria. These data provide evidence that hybridization and polyploidization, driving forces of terrestrial plant evolution, contribute to duckweed genetic diversity and may have shaped the phylogenetic history of these mainly asexual, aquatic plants.

Differential phytotoxic effect of silver nitrate (AgNO3) and bifunctionalized silver nanoparticles (AgNPs-Cit-L-Cys) on Lemna plants (duckweeds).

Duckweeds are aquatic plants often used in phytotoxic studies for their small size, simple structure, rapid growth, high sensitivity to pollutants and facility of maintaining under laboratory conditions. In this paper, induced phytotoxic effects were investigated in Lemna minor and Lemna minuta after exposition to silver nitrate (AgNO3) and silver nanoparticles stabilized with sodium citrate and L-Cysteine (AgNPs-Cit-L-Cys) at different concentrations (0, 20 and 50 mg/L) and times (7 and 14 days). Lemna species responses were evaluated analyzing plant growth (mat thickness, fresh and dry biomass, relative growth rate - RGR) and physiological parameters (chlorophyll - Chl, malondialdehyde - MDA, ascorbate peroxidase - APX and catalase - CAT). Ag content was measured in the fronds of the two Lemna species by inductively coupled plasma optical emission spectrometry. AgNO3 and AgNPs-Cit-L-CYs produced phytotoxic effects on both duckweed species (plant growth and Chl reduction, MDA increase) that enhanced in response to increasing concentrations and exposure times. AgNPs-Cit-L-Cys caused much less alteration in the plants compared to AgNO3 suggesting that the presence of bifunctionalized AgNPs-Cit-L-Cys have a reduced phytotoxic effect as compared to Ag+ released in water. Based on the physiological performance, L. minuta plants showed a large growth reduction and higher levels of chlorosis and stress in respect to L. minor plants, probably due to greater Ag+ ions accumulation in the fronds. Albeit with some differences, both Lemna species were able to uptake Ag+ ions from the aqueous medium, especially over a period of 14 days, and could be considered adapt as phytoremediation agents for decontaminating silver ion-polluted water.

Transcription Factor Networks in Leaves of Cichorium endivia: New Insights into the Relationship Between Photosynthesis and Leaf Development.

Cichorium endivia is a leafy crop closely related to Lactuca sativa that comprises two major botanical varieties characterized by a high degree of intraspecific morphological variation: var. latifolium with broad leaves (escarole) and var. crispum with narrow crisp curly leaves (endive). To investigate the relationship between leaf morphology and photosynthetic activity, escaroles and endives were used as a crop model due to the striking morphological diversity of their leaves. We constructed a leaf database for transcription factors (TFs) and photosynthesis-related genes from a refined C. endivia transcriptome and used RNA-seq transcriptomic data from leaves of four commercial endive and escarole cultivars to explore transcription factor regulatory networks. Cluster and gene co-expression network (GCN) analyses identified two main anticorrelated modules that control photosynthesis. Analysis of the GCN network topological properties identified known and novel hub genes controlling photosynthesis, and candidate developmental genes at the boundaries between shape and function. Differential expression analysis between broad and curly leaves suggested three novel TFs putatively involved in leaf shape diversity. Physiological analysis of the photosynthesis properties and gene expression studies on broad and curly leaves provided new insights into the relationship between leaf shape and function.

Combined effects of elevated CO2 and Cd-contaminated water on growth, photosynthetic response, Cd accumulation and thiolic components status in Lemna minor L.

The objective of this study was to investigate the combined effects of elevated CO2 and cadmium (Cd) treatments on growth, photosynthetic efficiency and phytoremediation ability in Lemna minor L. Plants of L. minor were exposed to different Cd concentrations (0, 1.5, 2.5 and 5 mg L(-1) Cd) for periods of 24, 48 and 72 h at ambient (AC) and at elevated (EC) CO2 (350 and 700 ppm, respectively). Cadmium concentration, bioconcentration factor, enzyme activities and thiols content enhanced in plants with the increase of Cd treatments, time of exposure and at both CO2 levels. Glutathione levels increased only at AC. Growth, photosynthetic and chlorophyll fluorescence parameters, and the reduced glutathione to oxidized glutathione ratio declined in plants with increasing exposure time, Cd treatments and at both CO2 levels. Our results suggested that the alleviation of toxicity, at low Cd doses, observed in L. minor grown at EC is dependent on both increased photosynthesis and an enhanced antioxidant capacity.

Perioperative anaphylactic risk score for risk-oriented premedication.

Basing on the current knowledge, this paper is aimed to review the core characteristics of the most relevant therapeutic agents (steroids and antihistamines), administered to prevent perioperative anaphylaxis. Moreover, the Authors propose the validation of a Global Anaphylactic Risk Score, built up by recording the individual scores related to the most relevant anaphylaxis parameters (i.e. medical history, symptoms and medication for asthma, rhinitis and urticaria etc) and by adding them on all together; the score could be used in the preoperative phase to evaluate the global anaphylactic risk and to prescribe risk-oriented premedication protocols.

Scenarios of diffusion and control of an influenza pandemic in Italy.

To predict the spread of a pandemic strain of influenza virus in Italy and the impact of control measures, we developed a susceptible-exposed, but not yet infectious-infectious-recovered, and no longer susceptible (SEIR) deterministic model with a stochastic simulation component. We modelled the impact of control measures such as vaccination, antiviral prophylaxis and social distancing measures. In the absence of control measures, the epidemic peak would be reached about 4 months after the importation of the first cases in Italy, and the epidemic would last about 7 months. When combined, the control measures would reduce the cumulative attack rate to about 4.2%, at best, although this would require an extremely high number of treated individuals. In accordance with international findings, our results highlight the need to respond to a pandemic with a combination of control measures.

Existence and uniqueness of endemic states for the age-structured S-I-R epidemic model.

The existence and uniqueness of positive steady states for the age structured S-I-R epidemic model with intercohort transmission is considered. Threshold results for the existence of endemic states are established for most cases. Uniqueness is shown in each case. Threshold used are explicitly computable in terms of demographic and epidemiological parameters of the model.

The HIV/AIDS epidemics among drug injectors: a study of contact structure through a mathematical model.

Numerical results of a model with variable infectivity for the dynamics of HIV/AIDS (human immunodeficiency virus/acquired immune deficiency syndrome) have been compared with the data of AIDS cases among intravenous drug users in Italy, especially in the Latium region. We examined several hypotheses about the dynamics of the epidemics; for each we obtained, mainly through a least-square approach but also minimizing a different quantity, a best-fit estimate of the parameters. In the simplest model, the population is assumed to be homogeneous, and we estimate contact rate and year of start of the epidemics, obtaining a good fit up to 1989, less so after. A substantial increase in fit is obtained in assuming either a decrease of the contact rate over time or a heterogeneous population with a smaller active group. We have also compared models with different infectivity curves during the incubation period: the assumption of constant infectivity is untenable, whereas the often suggested hypothesis of a peak in infectivity shortly after infection seems to be in agreement with data.

Inhibition of human leukocyte elastase by chemically and naturally oversulfated galactosaminoglycans.

Several samples of oversulfated chondroitin and dermatan were obtained by chemical sulfation and by SAX-HPLC enrichment. The starting products and oversulfated products were tested as potential inhibitors of human leukocyte elastase, an enzyme hypothesized to be involved in the etiology of diseases such as emphysema, atherosclerosis, and rheumatoid arthritis. Chemical oversulfation (SO3H/COOH 1.6-3.2), preferentially occurring at C-6 of galactosamine residues, was found generally to increase the inhibitory power on elastase. Chemically oversulfated galactosaminoglycans thus have potential as therapeutic agents, considering that they produce non-significant effects on the hemocoagulative system. Two naturally oversulfated dermatans sulfate (SO3H/COOH ca. 1.2), mainly oversulfated at C-2 of iduronic acid residues, showed comparatively higher anticoagulant activity (in the HC-II mediated thrombin inhibition test).

Xenobiotic-metabolizing enzyme systems in test fish. V. Comparative studies of liver microsomal glucuronyltransferases.

UDPG-glucuronyltransferase (GT) activities have been determined in the hepatic microsomes of fish species recommended by OECD for some (eco)toxicological tests. Due to the heterogeneity of this enzyme family, different chemicals were used as substrate: 4-nitrophenol (4NP), 4 methylumbelliferone (4MU), and 2- and 4-hydroxybiphenyl (2OHB and 4OHB). The 4NP-GT and 2OHB-GT activities of hepatic microsomes from all the species were linearly dependent on the substrate concentration (tested concentrations up to 2 and 0.5 mM, respectively). 4OHB-GT and 4MU-GT demonstrated different degrees of saturation in the range of substrate concentrations 0-0.5 mM and 0-0.3 mM, respectively. Specific activities ranged among the species usually within a factor of about 3. The highest ratios (up to 10) were occasionally found for 4MU-GT (between trout and golden orfe) and 2OHB-GT (between guppy and carp, zebra fish, or trout). These results confirm that GT activities in fish are much lower than in mammals.

An AIDS model with distributed incubation and variable infectiousness: applications to i.v. drug users in Latium, Italy.

An AIDS model with distributed incubation and variable infectiousness is considered and simulated via a second-order numerical method. The method is applied to the HIV epidemic among IV drug users in the Latium region of Italy, using available data on the length of the incubation period before the onset of AIDS, on the infectivity of infected individuals during that period, and on the demography of drug users. The contact rate is adjusted to match the actual number of AIDS cases. The sensitivity of the model to uncertainties in the parameters is finally investigated, by performing several simulations.

Intellectual functions and personality in subjects with noncongenital myotonic muscular dystrophy.

Mental retardation and personality disorders are commonly described among the symptoms of myotonic dystrophy. Nevertheless, this tendency is not supported by systematic studies performed on large samples, whose results are controversial. We studied the cognitive functions and personalities of a group of 28 patients, in whom myotonic dystrophy had commenced in juvenile or adult life. The severity of the disease was variable, but all subjects were self-sufficient. Only 7.1% of subjects showed low intelligence with deterioration of perceptual-motor functions. This was not correlated with the severity of their disease. Women had a substantially lower mean Wechsler-Bellevue score than men. The personality function study of the entire group showed no change of psychiatric relevance but did present a depressive attitude with marked somatic concern and difficulties in establishing relationships in social life.