Aphids (Hemiptera: Aphidoidea) on cultivated and self-sown plants in Greece

The present work covers original information on aphids (Hemiptera: Aphidoidea) from Greece during 1995–2005. The individual aphid taxa were collected from their host plants and identified. The plant taxa were classified in two major categories: cultivated and self-sown. The cultivated ones were classified as: herbaceous, climbing and trees. The selfsown ones were classified as: annual herbaceous, annual or biennial herbaceous, biennial or perennial herbaceous, perennial herbaceous, shrubby and trees Two hundred twelve plant taxa were identified on which 105 aphid taxa were recorded. We report 391 plant taxa-aphid taxa associations from which, 190 are referred to cultivated and 201 to self-shown plant taxa. Aphis gossypii was found to infest the widest spectrum of cultivated plant taxa whereas Brachycaudus helichrysi was found to infest the widest spectrum of self-sown plant taxa. Myzus persicae was found to infest the widest spectrum of the total number of plant taxa. Information for several economically unimportant aphid taxa in the area are also presented.     

Daily copper supplement effects on copper balance in trained subjects during prolonged restriction of muscular activity

The aim of this study was to assess the effect of a daily intake of copper supplements on negative copper balance during prolonged exposure to hypokinesia (decreased number of kilometers per day). During hypokinesia (HK), negative copper balance is shown by increased, not by decreased, serum copper concentration, as it happens in other situations. Studies were done during a 30-d prehypokinetic period and a 364-d hypokinetic period. Forty male trained volunteers aged 22–26 yr with a peak oxygen uptake of 66.4 mL/min/kg and with an average of 13.7 km/d running distance were chosen as subjects. They were equally divided into four groups: unsupplemented ambulatory control subjects (UACS), unsupplemented hypokinetic subjects (UHKS), supplemented hypokinetic subjects (SHKS), and supplemented ambulatory control subjects (SACS). The SACS and SHKS groups took 0.09 mg copper carbonate/kg body weight daily. The SHKS and UHKS groups were maintained under an average running distance of 1.7 km/d, whereas the SACS and UACS groups did not experience any modifications in their normal training routines. During the 30-d prehypokinetic period and the 346-d hypokinetic period, urinary excretion of copper, calcium, and magnesium and serum concentrations of copper, calcium, and magnesium were measured. Copper loss in feces and copper balance was also determined. In both UHKS and SHKS groups, urinary excretion of copper, calcium, and magnesium and concentrations of copper, magnesium, and calcium in serum increased significantly when compared with the SACS and UACS groups. Loss of copper in feces was also increased significantly in the SHKS and UHKS groups when compared with the UACS and SACS groups. Throughout the study, the copper balance was negative in the SHKS and UHKS groups, whereas in the SACS and UACS groups, the copper balance was positive. It was concluded that a daily intake of copper supplements cannot be used to prevent copper deficiency shown by increased copper concentration. Copper supplements also failed to prevent negative copper balance and copper losses in feces and urine in endurancetrained subjects during prolonged exposure to HK.     

Computational binding assays of antigenic peptides

Computer models can be combined with laboratory experiments for the efficient determination of (i) peptides that bind MHC molecules and (ii) T-cell epitopes. For maximum benefit, the use of computer models must be treated as experiments analogous to standard laboratory procedures. This requires the definition of standards and experimental protocols for model application. We describe the requirements for validation and assessment of computer models. The utility of combining accurate predictions with a limited number of laboratory experiments is illustrated by practical examples. These include the identification of T-cell epitopes from IDDM-, melanoma- and malaria-related antigens by combining computational and conventional laboratory assays. The success rate in determining antigenic peptides, each in the context of a specific HLA molecule, ranged from 27 to 71%, while the natural prevalence of MHC-binding peptides is 0.1–5%.     

Improved linkage map and thirty new microsatellite markers for rat Chromosome 10

An improved linkage map for rat Chromosome (Chr) 10 with two F₂ populations was constructed. Thirty new microsatellite markers were generated from a Chr 10-specific, small-insert genomic library and mapped to rat Chr 10. Among them were the rat homologs for the mouse gene for light and heavy chains of myeloperoxidase and human neurofibromatosis 1. Eight newly generated markers (D10Mco62, D10Mco63, D10Mco64, D10Mco65, D10Mco67, D10Mco68, D10Mco70, and D10Mco74) were mapped to the region of the rat Chr 10 blood pressure QTL. The availability of such markers may be instrumental in the search for genes responsible for the hypertension. Received: 13 July 1998 / Accepted: 9 September 1998     

Azospirillum brasilense glutamine synthetase: influence of the activating metal ions on the enzyme properties

The kinetic properties of the Mg²⁺-activated and Mn²⁺-activated glutamine synthetase (GS) of Azospirillum brasilense in the biosynthetic reaction were studied. The Mg²⁺-supported and Mn²⁺-supported GSs in an average state of adenylylation varied in pH optimum, maximum activity, saturation functions for ammonium and glutamate, affinity to substrates, and in the Me²⁺-ATP ratio required for the optimal enzyme activity. Seventeen other cations were tested for the maintenance of GS activity. The level of the latter and the kinetic behavior of the GS in A.brasilense is suggested to depend essentially on the concentrations of Mg²⁺, Mn²⁺ and Co²⁺, as well as on their ratio     

Selective grazing on Cryptomonas by Ceriodaphnia quadrangula fed a natural phytoplankton assemblage

Grazing of C. quadrangula from a Siberian forest pond on natural phytoplankton assemblages was studied in a modified flow-through system. Ceriodaphniastrongly selected subdominant Cryptomonas erosarather than the dominant diatoms of comparable size. Using Cryptomonas as the sole microalgae food, Ceriodaphnia demonstrated significant somatic and population growth. Seasonal biomass maximum of Ceriodaphnia and Cryptomonas coincidedin the pond. Although bacterial component cannot be excluded, it was concluded that Cryptomonaswas the principal algal food source for Ceriodaphnia.     

Marine molluscs and fish as biomarkers of pollution stress in littoral regions of the Red Sea, Mediterranean Sea and North Sea

The intensive development of industry and urban structures along the seashores of the world, as well as the immense increase in marine transportation and other activities, has resulted in the deposition of thousands of new chemicals and organic compounds, endangering the existence of organisms and ecosystems. The conventional single biomarker methods used in ecological assessment studies cannot provide an adequate base for environmental health assessment, management and sustainability planning. The present study uses a set of novel biochemical, physiological, cytogenetic and morphological methods to characterize the state of health of selected molluscs and fish along the shores of the German North Sea, as well as the Israeli Mediterranean and Red Sea. The methods include measurement of activity of multixenobiotic resistance-mediated transporter (MXRtr) and the system of active transport of organic anions (SATOA) as indicators of antixenobiotic defence; glutathione S-transferase (GST) activity as an indicator of biotransformation of xenobiotics; DNA unwinding as a marker of genotoxicity; micronucleus test for clastogenicity; levels of phagocytosis for immunotoxicity; cholinesterase (ChE) activity and level of catecholamines as indicators of neurotoxicity; permeability of external epithelia to anionic hydrophilic probe, intralysosomal accumulation of cationic amphiphilic probe and activity of non-specific esterases as indicators of cell/tissue viability. Complete histopathological examination was used for diagnostics of environmental pathology. The obtained data show that the activity of the defensive pumps, MXRtr and SATOA in the studied organisms was significantly higher in the surface epithelia of molluscs from a polluted site than that of the same species from control, unpolluted stations, providing clear evidence of response to stress. Enhanced frequency of DNA lesions (alkaline and acidic DNA unwinding) and micronucleus-containing cells was significantly higher in samples from polluted sites in comparison to those from the clean sites that exhibited genotoxic and clastogenic activity of the pollutants. In all the studied molluscs a negative correlation was found between the MXRtr levels of activity and the frequency of micronucleus-containing hemocytes. The expression of this was in accordance with the level of pollution. The complete histopathological examination demonstrates significantly higher frequencies of pathological alterations in organs of animals from polluted sites. A strong negative correlation was found between the frequency of these alterations and MXRtr activity in the same specimens. In addition to these parameters, a decrease in the viability was noted in molluscs from the polluted sites, but ChE activities remained similar at most sites. The methods applied in our study unmasked numerous early cryptic responses and negative alterations of health in populations of marine biota sampled from the polluted sites. This demonstrates that genotoxic, clastogenic and pathogenic xenobiotics are present and act in the studied sites and this knowledge can provide a reliable base for consideration for sustainable development. Received: 2 March 1999 / Received in revised form: 2 August 1999 / Accepted: 3 August 1999     

Developmentally Regulated Expression of Persyn, a Member of the Synuclein Family, in Skin

Synucleins constitute a group of unique, evolutionarily conserved proteins that are expressed predominantly in neurons of the central and peripheral nervous system. Although the normal cellular functions of synucleins are not clear, these proteins have been implicated in various neurodegenerative conditions in humans. We found that persyn, a recently characterized member of the synuclein family, is expressed not only in the nervous system but also in the stratum granulosum of the epidermis of neonatal and adult mice. This finding together with our recent observations that persyn influences neurofilament network integrity in sensory neurons raises the possibility that persyn in skin could be involved in modulation of the keratin network.     

Modes of Action of Five Different Endopectate Lyases from Erwinia chrysanthemi 3937

Five endopectate lyases from the phytopathogenic bacterium Erwinia chrysanthemi, PelA, PelB, PelD, PelI, and PelL, were analyzed with respect to their modes of action on polymeric and oligomeric substrates (degree of polymerization, 2 to 8). On polygalacturonate, PelB showed higher reaction rates than PelD, PelI, and PelA, whereas the reaction rates for PelL were extremely low. The product progression during polygalacturonate cleavage showed a typical depolymerization profile for each enzyme and demonstrated their endolytic character. PelA, PelI, and PelL released oligogalacturonates of different sizes, whereas PelD and PelB released mostly unsaturated dimer and unsaturated trimer, respectively. Upon prolonged incubation, all enzymes degraded the primary products further, to unsaturated dimer and trimer, except for PelL, which degraded the primary products to unsaturated tetramer and pentamer in addition to unsaturated dimer and trimer. The bond cleavage frequencies on oligogalacturonates revealed differences in the modes of action of these enzymes that were commensurate with the product progression profiles. The preferential products formed from the oligogalacturonates were unsaturated dimer for PelD, unsaturated trimer for PelB, and unsaturated tetramer for PelI and PelL. For PelA, preferential products were dependent on the sizes of the oligogalacturonates. Whereas PelB and PelD displayed their highest activities on hexagalacturonate and tetragalacturonate, respectively, PelA, PelI, and PelL were most active on the octamer, the largest substrate used. The bond cleavage frequencies and reaction rates were used to estimate the number of subsites of each enzyme.