A Survey of Phytotoxic Microbial and Plant Metabolites as Potential Natural Products for Pest Management

Phytotoxic microbial metabolites produced by certain phytopathogenic fungi and bacteria, and a group of phytotoxic plant metabolites including Amaryllidacea alkaloids and some derivatives of these compounds were evaluated for algicide, bactericide, insecticide, fungicide, and herbicide activities in order to discover natural compounds for potential use in the management and control of several important agricultural and household structural pests. Among the various compounds evaluated: i) ophiobolin A was found to be the most promising for potential use as a selective algicide; ii) ungeremine was discovered to be bactericidal against certain species of fish pathogenic bacteria; iii) cycasin caused significant mortality in termites; iv) cavoxin, ophiobolin A, and sphaeropsidin A were most active towards species of plant pathogenic fungi; and v) lycorine and some of its analogues (1‐O‐acetyllycorine and lycorine chlorohydrate) were highly phytotoxic in the herbicide bioassay. Our results further demonstrated that plants and microbes can provide a diverse and natural source of compounds with potential use as pesticides.     

Fluorescence emission and enhanced photochemical stability of Zn-5-triethyl ammonium methyl salicylidene ortho-phenylendiiminate interacting with native DNA

The photophysical and photochemical properties of the cationic Zn^II complex of 5-triethyl ammonium methyl salicylidene ortho-phenylendiimine (ZnL²⁺) interacting with native DNA were investigated by steady state and time-resolved fluorescence spectroscopies. Experimental results indicate that, in the presence of DNA, ZnL²⁺ is efficiently protected from a photochemical process, which occurs when it is in the free state dispersed in aqueous solution. The analysis of the absorption and emission spectra of ZnL²⁺, both stored in the dark and after exposure to tungsten lamp light for 24 h, corroborated by quantum chemical calculations, allowed us to point out that ZnL²⁺ undergoes a photoinduced two-electron oxidation process. According to this picture, the protective action of DNA toward the intercalated ZnL²⁺ was attributed to an effective inhibition of the ZnL²⁺ photooxidation. In this context, it can be considered that DNA-intercalated ZnL²⁺ is located in a region more hydrophobic than that sensed in the bulk water solvent. Moreover, by a thorough analysis of steady state and time-resolved fluorescence spectra, the interaction process can be consistently explained in terms of a complete intercalation of the complex molecules and that the polarity of the environment sensed by intercalated ZnL²⁺ is comprised between that of methanol and ethanol.     

Proteomics and transcriptomics investigation on longissimus muscles in Large White and Casertana pig breeds

Consumer complaints against the blandness of modern lean meat and the frequent reference to the more strongly flavored meat that was available years ago have prompted reconsideration of high fat-depositing typical pig breeds. Casertana and Large White pig breeds are characterized by a different tendency toward fat accumulation as they exhibit opposite genetic and physiological traits with respect to the energy metabolism. These physiological differences were investigated in longissimus lumborum muscles through proteomics (2-DE, MS/MS) and microarray approaches. Data were analyzed for pathway and network analyses, as well as GO term enrichment of biological functions. As a result, Casertana showed a greater amount of proteins involved in glycolitic metabolism and mainly rely on fast-mobilizable energy sources. Large White overexpressed cell cycle and skeletal muscle growth related genes. Metabolic behavior and other implications are discussed.     

Uncoupling and turnover in a Cl-/H+ exchange transporter

The CLC-family protein CLC-ec1, a bacterial homologue of known structure, stoichiometrically exchanges two Cl(-) for one H(+) via an unknown membrane transport mechanism. This study examines mutations at a conserved tyrosine residue, Y445, that directly coordinates a Cl(-) ion located near the center of the membrane. Mutations at this position lead to "uncoupling," such that the H(+)/Cl(-) transport ratio decreases roughly with the volume of the substituted side chain. The uncoupled proteins are still able to pump protons uphill when driven by a Cl(-) gradient, but the extent and rate of this H(+) pumping is weaker in the more uncoupled variants. Uncoupling is accompanied by conductive Cl(-) transport that is not linked to counter-movement of H(+), i.e., a "leak." The unitary Cl(-) transport rate, measured in reconstituted liposomes by both a conventional initial-velocity method and a novel Poisson dilution approach, is approximately 4,000 s(-1) for wild-type protein, and the uncoupled mutants transport Cl(-) at similar rates.     

Factors affecting the distribution of<Emphasis Type="Italic">Sorex samniticus</Emphasis>, an endemic Italian shrew,in an heterogeneous landscape

We studied the factors affecting the distribution of an endemic shrewSorex samniticus Altobello, 1926 in the Province of Siena, central Italy. Distribution data were obtained by examining pellets from 31 barn owlTyto alba sites (roosts) over a period spanning from 1974 to 2005. We constructed a model using logistic regression analysis on presence/absence data. Results show that an increase in forest dominated byQuercus cerris andCastanea sativa led to the local extinction of this species. Results were confirmed through the examination of one box, with 3044 prey items deposited in layers, that documents the expansion of the species in that area following increased logging ofQuercus cerris andCastanea sativa forests. Cessation of logging has again led to the absence of the species from the area. We discuss these results from the perspective of ecological network planning, showing that utilisation of non-detailed maps, such as Corine Land Cover, that do not distinguish between the various kind of broadleaved forests is inadequate to describe the finer grade of habitat selection of this small mammal.     

Electromagnetic fields produced by GSM cellular phones and heart rate variability

In this study, 26 healthy young volunteers were submitted to 900 MHz (2 W) GSM cellular phone exposure and to sham exposure in separate sessions. The study was designed to assess cardiac regulatory mechanism in different autonomic nervous system (ANS) states during exposure to low-intensity EMF. Rest-to-stand protocol was applied to evaluate ANS in quiet condition (rest, vagal prevalence) and after a sympathetic activation (stand). The procedure is conducted twice in a double-blind design: once with a genuine EMF exposure and once with a sham exposure (at least 24 h apart). During each session three-leads electrocardiograms were recorded and RR series extracted off-line. Time domain and frequency domain HRV parameters were calculated in every phase of the protocol and during different exposures. The analysis of the data show there was no statistically significant effect due to EMF exposure both on main (i.e., RR mean) and most of the other HRV parameters. A weak interaction between some HRV parameters (i.e., SDNN, TINN, and triangular index in time domain and LF power in frequency domain analysis) and RF exposure was observed and this effect seems to be gathered around the sympathetic response to stand.     

Carbonic anhydrase and matrix metalloproteinase inhibitors. Inhibition of human tumor-associated isozymes IX and cytosolic isozyme I and II with sulfonylated hydroxamates

A series of sulfonylated hydroxamates were synthesized and evaluated as dual inhibitors of both human carbonic anhydrases (hCAs) and matrix metalloproteinases (MMPs), two metalloenzyme families involved in carcinogenesis and tumor invasion processes. The new derivatives were tested on three CA isozymes, the cytosolic isozymes I and II, and the transmembrane, tumor-associated isozyme IX, and also on human gelatinases (MMP-2 and MMP-9). Some of the new derivatives proved to be potent and selective inhibitors of CA II, but only compounds 3b and 6b, devoid of the arylsulfonyl moiety, proved to have a better inhibitory activity on hCA IX than on hCA I and II, in the micromolar range.     

Carbonic anhydrase activators: the first activation study of the human secretory isoform VI with amino acids and amines

The secretory isozyme of human carbonic anhydrase (hCA, EC 4.2.1.1), hCA VI, has been cloned, expressed, and purified in a bacterial expression system. The kinetic parameters for the CO(2) hydration reaction proved hCA VI to possess a k(cat) of 3.4 x 10(5)s(-1) and k(cat)/K(M) of 4.9 x 10(7)M(-1)s(-1) (at pH 7.5 and 20 degrees C). hCA VI has a significant catalytic activity for the physiological reaction, of the same order of magnitude as the ubiquitous isoform CA I or the transmembrane, tumor-associated isozyme CA IX. A series of amino acids and amines were shown to act as CA VI activators, with variable efficacies. l-His, l-Trp, and dopamine showed weak CA VI activating effects (K(A)s in the range of 21-42 microM), whereas d-His, d-Phe, l-DOPA, l-Trp, serotonin, and some pyridyl-alkylamines were better activators, with K(A)s in the range of 13-19 microM. The best CA VI activators were l-Phe, d-DOPA, l-Tyr, 4-amino-l-Phe, and histamine, with K(A)s in the range of 1.23-9.31 microM. All these activators enhance k(cat), having no effect on K(M), participating thus in the rate determining step in the catalytic cycle, the proton transfer reactions between the enzyme active site and the environment.     

Endogenous microRNA can be broadly exploited to regulate transgene expression according to tissue, lineage and differentiation state

We have shown previously that transgene expression can be suppressed in hematopoietic cells using vectors that are responsive to microRNA (miRNA) regulation. Here we investigate the potential of this approach for more sophisticated control of transgene expression. Analysis of the relationship between miRNA expression levels and target mRNA suppression suggested that suppression depends on a threshold miRNA concentration. Using this information, we generated vectors that rapidly adjust transgene expression in response to changes in miRNA expression. These vectors sharply segregated transgene expression between closely related states of therapeutically relevant cells, including dendritic cells, hematopoietic and embryonic stem cells, and their progeny, allowing positive/negative selection according to the cells' differentiation state. Moreover, two miRNA target sites were combined to restrict transgene expression to a specific cell type in the liver. Notably, the vectors did not detectably perturb endogenous miRNA expression or regulation of natural targets. The properties of miRNA-regulated vectors should allow for safer and more effective therapeutic applications.